Abstract: BACKGROUND: Three distinctly different lineages of head and body lice are known to parasitize humans. One lineage includes head and body lice and is currently worldwide in distribution (type A). The other 2 (types B and C) include only head lice and are geographically restricted. It was hypothesized that head louse phylotypes were exchanged only recently, after European exploration and colonization (after Columbus). METHODS: To determine which louse type or types were found in the Americas before European colonization, we used polymerase chain reaction in 2 laboratories to amplify DNA from 2 genes (Cytb and Cox1) belonging to 1000-year-old lice collected from Peruvian mummies. RESULTS: Only the worldwide type (type A) was found. Therefore, this phylotype was worldwide before European colonization, as type A lice were common in Europe, Africa, and Asia. CONCLUSIONS: The findings of this study show that several phylotypes of head lice have coexisted for centuries in humans and support the claim that type A lice were present in the Americas before the time of Columbus.
Abstract: PCR screening of blood specimens taken from 195 patients with serologically confirmed scrub typhus in three Thai provinces detected the 56-kDa protein-encoding gene from Orientia tsutsugamushi in ten (5%) patients. Significant genetic diversity was found among the ten amplicons, with nine new genotypes identified that were different from those found previously in Thailand. Phylogenetically, the ten sequences obtained in the present study and sequences from 71 strains characterised previously were distributed into several clusters that included the Karp, Gilliam, Kuroki, Saitama, Kawasaki and Kato clusters. Two of the new genotypes found in the present study clearly belonged to the Karp cluster. However, the other new genotypes formed three different clusters, including one cluster that appeared to be distant from all previously known clusters, and which may therefore be representative of a previously undescribed serotype. Other genotypes formed two other clusters that may also be associated with undescribed serotypes.
Abstract: "Nanobacteria" are nanometer-scale spherical and ovoid particles which have spurred one of the biggest controversies in modern microbiology. Their biological nature has been severely challenged by both geologists and microbiologists, with opinions ranging from considering them crystal structures to new life forms. Although the nature of these autonomously replicating particles is still under debate, their role in several calcification-related diseases has been reported. In order to gain better insights on this calciferous agent, we performed a large-scale project, including the analysis of "nanobacteria" susceptibility to physical and chemical compounds as well as the comprehensive nucleotide, biochemical, proteomic, and antigenic analysis of these particles. Our results definitively ruled out the existence of "nanobacteria" as living organisms and pointed out the paradoxical role of fetuin (an anti-mineralization protein) in the formation of these self-propagating mineral complexes which we propose to call "nanons." The presence of fetuin within renal calculi was also evidenced, suggesting its role as a hydroxyapatite nucleating factor.
Abstract: In African tick bite fever (ATBF), inoculation eschar - resulting from disruption of the cutaneous barrier - may be a risk factor for cellulitis. We report 2 cases of ATBF associated with cellulitis. A 77-year-old woman was referred for severe leg cellulitis upon returning from sub-Saharan Africa. She developed erythematous macules. Rickettsia africae was detected by PCR assay from a skin biopsy specimen, and ATBF diagnosis was confirmed. A 75-year-old man was hospitalized after his return from Zimbabwe for a maculopapular exanthema and erysipelas-like rash of the leg. The diagnosis of cellulitis associated with ATBF was confirmed by PCR and serological methods. Both patients were treated for ATBF and cellulitis by a combination of doxycycline and beta-lactam antibiotics, and both had a good recovery. Inoculation eschar may be a risk factor for cellulitis; thus, we hypothesize a non-fortuitous association between ATBF and cellulitis.
Abstract: DNA extracted from 363 ticks collected in Ethiopia and 9 ticks collected in Chad, Africa were screened by PCR to detect DNA from spotted fever group rickettsiae. Fifteen ticks (4.1%) collected in Ethiopia and one tick (11%) collected in Chad tested positive when PCR targeting the gltA and ompA rickettsial genes was performed. PCR-positive products of the gltA and ompA genes were used for DNA sequencing. Rickettsia africae was detected in 12/118 Amblyomma lepidum and in 1/2 A. variegatum. Also, 2/12 Hyalomma marginatum rufipes collected in Ethiopia and one H. marginatum rufipes collected in Chad were positive for R. aeschlimannii. Our results confirm the previously reported presence of R. africae in Ethiopia and also show the first evidence of R. aeschlimannii in ticks collected in Ethiopia and Chad.
Abstract: Background. @nbsp; Whipple disease is a chronic infection caused by Tropheryma whipplei. Trimethoprim-sulfamethoxazole is recommended for treatment of Whipple disease but is associated with treatment failure. T. whipplei is resistant in vitro to trimethoprim, because the gene targeted by this agent is missing. Methods. @nbsp; A patient experienced clinical failure during treatment with trimethoprim-sulfamethoxazole. The gene encoding the enzyme putatively believed to be dihydropteroate synthase (DHPS), the target of sulfamethoxazole, was amplified and sequenced for 20 T. whipplei strains from our laboratory and for isolates recovered from a case patient at the time of diagnosis and the time of treatment failure. An Escherichia coli knockout strain for this gene was complemented with the sequences from a susceptible strain and from isolates recovered from the case patient. Susceptibilities of complemented E. coli to sulfamethoxazole were tested. Results. @nbsp; The target gene was identified among genes encoding a unique trifunctional enzyme in which DHPS is combined with the 2 preceding enzymes of the folate biosynthesis pathway. Changes in the amino acid sequence of putative DHPS were detected in the case patient. Gene complementation showed that the gene encoding putative DHPS restored the folate biosynthesis pathway and susceptibility to sulfamethoxazole, whereas the mutated sequence was associated with sulfamethoxazole resistance. Conclusions. @nbsp; Antibiotic susceptibility of fastidious bacteria such as T. whipplei can be evaluated by means of gene complementation techniques. Mutations in the target gene of sulfamethoxazole appear during treatment.
Abstract: To the Editor: Rickettsia sibirica subsp. mongolitimonae is an intracellular bacterium that belongs to the species R. sibirica. To date, only 11 cases of infection with this bacterium have been reported. We report a case in a pregnant woman with ocular vasculitis.
Abstract: OBJECTIVES: Bartonella sp. are intracellular bacteria associated with an increasing number of clinical manifestations but with few published data on in vitro susceptibility testing of antibiotics. Our objective was to evaluate in vitro antibiotic susceptibilities of 20 new Bartonella isolates from animals in Australia. METHODS: MICs were determined using Etest assay on Columbia agar supplemented with 5% horse blood. The presence of mutations in the quinolone-resistance-determining region (QRDR) of gyrA was searched for after PCR amplification and DNA sequencing using specific oligonucleotide primers. RESULTS: Bartonella isolates from Australia were susceptible to rifampicin, tetracyclines, beta-lactam and macrolide compounds but were resistant to vancomycin. We found heterogeneity of susceptibility for fluoroquinolones with ciprofloxacin being more effective (MICs from 0.06 to 0.5 mg/L) than ofloxacin (MICs from 0.5 to 4 mg/L). This heterogeneity was linked to a natural mutation Ser-83-->Ala (Escherichia coli numbering) in the QRDR. Surprisingly, this mutation was also present in the QRDR of Bartonella henselae, Bartonella quintana and Bartonella bacilliformis. CONCLUSIONS: Etest is a sensitive and reliable assay for evaluation of antibiotic susceptibility in the genus Bartonella. The higher sensitivity of this method allowed us to detect heterogeneity of susceptibility among fluoroquinolones that was associated with natural mutation in the QRDR of the DNA gyrase. Because a high level of resistance to fluoroquinolones due to a second mutation may be obtained easily in vitro, we believe that fluoroquinolone compounds should be avoided for the treatment of any Bartonella-related diseases.
Abstract: BACKGROUND: The reservoir of the agent of Whipple disease is unknown. Asymptomatic carriage of Tropheryma whipplei in human stool and saliva is controversial. METHODS: Stools and saliva specimens from 231 workers at a sewage treatment facility and from 10 patients with Whipple disease, stool specimens from 102 healthy people, and stool specimens from 127 monkeys or apes were tested for T. whipplei DNA by a quantitative real-time polymerase chain reaction with probe detection. Genotyping and culture of T. whipplei-positive samples were performed. RESULTS: Asymptomatic carriage in stool was found in humans (ranging from a prevalence of 4% in the control group to 12% among a subgroup of sewer workers) but not in monkeys and apes. The T. whipplei load in stool was significantly lower in carriers than in patients with Whipple disease (P < .001). There was a significant prevalence gradient associated with employment responsibilities at the sewage treatment facility: workers who cleaned the underground portion of the sewers were more likely than other workers to carry T. whipplei in stool. Seven of 9 sewer workers tested positive 8 months later. Patients with Whipple disease were significantly more likely to have T. whipplei-positive saliva specimens (P = .005) and had a significantly greater T. whipplei load in saliva (P = .015), compared with asymptomatic stool carriers from the sewage facility. All non-stool carriers had T. whipplei-negative saliva specimens. T. whipplei strains were heterogeneic among sewer workers but identical within individual workers. CONCLUSION: Chronic asymptomatic carriage of T. whipplei occurs in humans. Bacterial loads are lower in asymptomatic carriers, and the prevalence of carriage increases with exposure to sewage.
Abstract: Tropheryma whipplei, the causative agent of Whipple's disease, is associated with various clinical manifestations as well as an asymptomatic carrier status, and it exhibits genetic heterogeneity. However, relationships that may exist between environmental and clinical strains are unknown. Herein, we developed an efficient genotyping system based on four highly variable genomic sequences (HVGSs) selected on the basis of genome comparison. We analysed 39 samples from 39 patients with Whipple's disease and 10 samples from 10 asymptomatic carriers. Twenty-six classic gastrointestinal Whipple's disease associated with additional manifestations, six relapses of classic Whipple's disease (three gastrointestinal and three neurological relapses), and seven isolated infections due to T. whipplei without digestive involvement (five endocarditis, one spondylodiscitis and one neurological infection) were included in the study. We identified 24 HVGS genotypes among 39 T. whipplei DNA samples from the patients and 10 T. whipplei DNA samples from the asymptomatic carriers. No significant correlation between HVGS genotypes and clinical manifestations of Whipple's disease, or asymptomatic carriers, was found for the 49 samples tested. Our observations revealed a high genetic diversity of T. whipplei strains that is apparently independent of geographical distribution and unrelated to bacterial pathogenicity. Genotyping in Whipple's disease may, however, be useful in epidemiological studies.
Abstract: It is critical to avoid delays in detecting strain manipulations, such as the addition/deletion of a gene or modification of genes for increased virulence or antibiotic resistance, using genome analysis during an epidemic outbreak or a bioterrorist attack. Our objective was to evaluate the efficiency of genome analysis in such an emergency context by using contigs produced by pyrosequencing without time-consuming finishing processes and comparing them to available genomes for the same species. For this purpose, we analyzed a clinical isolate of Francisella tularensis subspecies holarctica (strain URFT1), a potential biological weapon, and compared the data obtained with available genomic sequences of other strains. The technique provided 1,800,530 bp of assembled sequences, resulting in 480 contigs. We found by comparative analysis with other strains that all the gaps but one in the genome sequence were caused by repeats. No new genes were found, but a deletion was detected that included three putative genes and part of a fourth gene. The set of 35 candidate LVS virulence attenuation genes was identified, as well as a DNA gyrase mutation associated with quinolone resistance. Selection for variable sequences in URFT1 allowed the design of a strain-specific, highly effective typing system that was applied to 74 strains and six clinical specimens. The analysis presented herein may be completed within approximately 6 wk, a duration compatible with that required by an urgent context. In the bioterrorism context, it allows the rapid detection of strain manipulation, including intentionally added virulence genes and genes that support antibiotic resistance.
Abstract: BACKGROUND: Tropheryma whipplei, the agent of Whipple's disease (WD), has been recently isolated and the genomes of two isolates have been fully sequenced. Previous diagnosis tools for the diagnosis of the disease used sequence analysis of the 16S rRNA gene. Using this target gene, the high percentage of detection of the bacterium in saliva of healthy people was in contrast to the negative results obtained with specific target genes. The aim of our study was to compare previously published primers targeting the 16S rRNA gene to real-time PCR with Taqman* probes targeting specific repeat genes only found in the genome of T. whipplei in a series of 57 saliva from healthy people. RESULTS: Although the specific real-time PCR assays with both primers and probes were negative for all the samples, 13 out of 57 samples were positive with different primers previously reported targeting the 16S rRNA gene. Among the positive samples, 8 yielded a 231-bp sequence that was 99.1% identical to that of Actinomyces odontolyticus, 2 yielded a 226-bp that was 99.6% identical to that of A. turicensis, and 3 yielded a 160-bp sequence that was 98.5% identical to that of Capnocytophaga gingivalis. We found that the C. gingivalis and A. odontolyticus 16S rRNA sequences obtained in our study share more than 80% homology with the corresponding 16S rRNA sequences of the T. whipplei genomes especially at 5' and 3' end. CONCLUSION: Asymptomatic carriers of T. whipplei in saliva may exist but their prevalence is much lower than those previously reported. Testing the specificity of designed primers is critical to avoid false positive detection of T. whipplei. In atypical case we recommend to test two different specific target genes before concluding.
Abstract: Chloroquine (CQ) and its hydroxyl analogue hydroxychloroquine (HCQ) are weak bases with a half-century long use as antimalarial agents. Apart from this antimalarial activity, CQ and HCQ have gained interest in the field of other infectious diseases. One of the most interesting mechanisms of action is that CQ leads to alkalinisation of acid vesicles that inhibit the growth of several intracellular bacteria and fungi. The proof of concept of this effect was first used to restore intracellular pH allowing antibiotic efficacy for Coxiella burnetii, the agent of Q fever, and doxycycline plus HCQ is now the reference treatment for chronic Q fever. There is also strong evidence of a similar effect in vitro against Tropheryma whipplei, the agent of Whipple's disease, and a clinical trial is in progress. Other bacteria and fungi multiply in an acidic environment and encouraging in vitro data suggest that this concept may be generalised for all intracellular organisms that multiply in an acidic environment. For viruses, CQ led to inhibition of uncoating and/or alteration of post-translational modifications of newly synthesised proteins, especially inhibition of glycosylation. These effects have been well described in vitro for many viruses, with human immunodeficiency virus (HIV) being the most studied. Preliminary in vivo clinical trials suggest that CQ alone or in combination with antiretroviral drugs might represent an interesting way to treat HIV infection. In conclusion, our review re-emphasises the paradigm that activities mediated by lysosomotropic agents may offer an interesting weapon to face present and future infectious diseases worldwide.
Abstract: BACKGROUND: To date, 6 tick-borne rickettsiae pathogenic for humans are known to occur in Africa and 4 of them were first identified in ticks before being recognized as human pathogens. RESULTS: We examined 33 and 5 Amblyomma tholloni ticks from African elephants in the Central African Republic and Gabon, respectively, by PCR amplification and sequencing of a part of gltA and ompA genes of the genus Rickettsia. The partial sequences of gltA and ompA genes detected in tick in Gabon had 99.1% similarity with those of R. heilongjiangensis and 97.1% with those of Rickettsia sp. HL-93 strain, respectively. The partial gltA and ompA gene sequences detected in tick in the Central African Republic were 98.9% and 95.1% similar to those of Rickettsia sp. DnS14 strain and R. massiliae, respectively. Phylogenetic analysis showed Rickettsia sp. detected in Gabon clusters with R. japonica and R. heilongjiangensis in a phylogenetic tree based on the partial gltA and ompA genes. The genotype of the Rickettsia sp. detected in the Central African Republic is close to those of R. massiliae group in the phylogenetic tree based on partial gltA gene sequences, and distantly related to other rickettsiae in the tree based on partial ompA gene. CONCLUSION: The degrees of similarity of partial gltA and ompA genes with recognized species indicate the rickettsiae detected in this study may be new species although we could only study the partial sequences of 2 genes regarding the amount of DNA that was available. We propose the Rickettsia sp. detected in Gabon be provisionally named "Rickettsia sp. stain Davousti" and Rickettsia sp. detected in the Central African Republic be named "Rickettsia sp. strain Uilenbergi".
Abstract: OBJECTIVES: Bartonella bacilliformis is the aetiological agent of Carrion's disease. Although ciprofloxacin, rifampicin and erythromycin have been successfully used in the treatment of the disease, failures and relapses have been reported. The objective of our study was to select in vitro mutants resistant to antibiotics in order to determine the frequency of mutations and to characterize the mechanism of resistance at the molecular level. METHODS: Antibiotic-resistant mutants were selected by serial passages of bacteria on blood agar plates containing antibiotics. Candidate genes involved in resistance were amplified and sequenced and compared in order to look at mutations associated with antibiotic resistance. RESULTS: Ciprofloxacin-, rifampicin- and erythromycin-resistant mutants were obtained after five, three and four passages, respectively. Conversely, no mutant was obtained with either gentamicin or doxycycline even after 16 passages. The ciprofloxacin mutant contained an amino acid change at position 87 (Asp --> Asn) in its quinolone resistance-determining region of the DNA gyrase protein, whereas the rifampicin-resistant strain had an amino acid change at position 531 (Ser --> Phe) in the rifampicin resistance-determining region of the rpoB gene. Similarly, the erythromycin-resistant mutant showed an A2058G mutation in the 23S rRNA gene. CONCLUSIONS: According with the current knowledge on the treatment of human bartonellosis, we believe that doxycycline in association with gentamicin may be the preferred regimen for the treatment of the acute and eruptive stages of Carrion's disease, but clinical trials are warranted to support our findings.
Abstract: Q fever is a worldwide-occurring zoonosis caused by Coxiella burnetii. Better knowledge of the disease and of evolving diagnostics can enable recognition of unusual manifestations. Reported here are four cases of Q fever osteoarticular infections in adults: two cases of Q fever tenosynovitis, which represent the first two reports of this infection, and two cases of Q fever spondylodiscitis complicated by paravertebral abscess. In addition, the literature is reviewed on the 15 previously reported cases of Q fever osteoarticular infection, six of which were vertebral infections. Osteomyelitis is the usual manifestation Q fever osteoarticular infection. Because its onset is frequently insidious, diagnosis is usually delayed. The main differential diagnosis is mycobacterial infection, based on the histological granulomatous presentation of lesions. Whereas serology is the reference diagnostic method for Q fever, detection of C. burnetii in tissue specimens by PCR and cell culture provides useful additional evidence of infection. Culture-negative osteoarticular samples with granulomatous presentation upon histological examination should raise suspicion of Q fever.
Abstract: Rickettsiae are in many places of the world emerging or reemerging pathogens. The spotted fevers group (SFG) composes a large group of tick- and mite-borne zoonotic infections that are caused by closely related rickettsiae. The SFG rickettsiae of Southeast Asia are yet to be identified. Earlier reports have documented the endemicity of rickettsioses among adults in the Himalayan belt but no confirmed case of spotted fever have been reported from this region of India. We present two cases of SFG rickettsioses; from the northern hilly region of India that were confirmed using specific microimmunofluorescence assay.
Abstract: We report, for the first time, serologic evidence of Rickettsia felis and R. aeschlimannii infections acquired in Tunisia from 1998 to 2003. We found that most patients with antibodies against both R. conorii and R. typhi had serologic evidence of R. felis infection.
Abstract: Rickettsial diseases have not been described previously from Laos, but in a prospective study, acute rickettsial infection was identified as the cause of fever in 115 (27%) of 427 adults with negative blood cultures admitted to Mahosot Hospital in Vientiane, Laos. The organisms identified by serologic analysis were Orientia tsutsugamushi (14.8%), Rickettsia typhi (9.6%), and spotted fever group rickettsia (2.6% [8 R. helvetica, 1 R. felis, 1 R. conorii subsp. indica, and 1 Rickettsia "AT1"]). Patients with murine typhus had a lower frequency of peripheral lymphadenopathy than those with scrub typhus (3% vs. 46%, p<0.001). Rickettsioses are an underrecognized cause of undifferentiated febrile illnesses among adults in Laos. This finding has implications for the local empiric treatment of fever.
Abstract: BACKGROUND: Bartonella quintana, the etiological agent of bacillary angiomatosis (BA), causes endothelial cell proliferation. Erythromycin has dramatic effects on BA, and the effects are largely unexplained by the compound's bacteriostatic properties. Our aim here was to evaluate the possibility that erythromycin alters angiogenesis. METHODS: The effect of erythromycin on B. quintana-induced endothelial cell proliferation was studied using a wild-type strain and an erythromycin-resistant B. quintana mutant. The latter was generated by serial subcultures on blood agar plates. RESULTS: We show that erythromycin significantly inhibits the proliferation of dermal microvascular endothelial cells induced either by wild-type B. quintana or by our erythromycin-resistant mutant. Doxycycline and gentamycin failed to exert such an effect. Finally, we found that the resistant strain harbored a 27-bp insertion in the highly conserved region of the gene encoding the ribosomal protein L4; this insertion may explain the existence of the resistance to erythromycin. CONCLUSION: The data presented here indicate that erythromycin profoundly down-modulates endothelial cell proliferation irrespective of its bacteriostatic effects and suggest that this may be a key component of the efficacy of the compound in the treatment of patients with BA.
Abstract: We report the first documented case of endocarditis in a man infected with Bartonella alsatica, which causes bacteremia in healthy wild rabbits. B. alsatica was identified by serology and culture and by PCR of an aortic valve specimen. B. alsatica should be added to the list of zoonotic agents of blood culture-negative endocarditis.
Abstract: The adult patients who, between July 2001 and June 2002, presented at any of five hospitals in Thailand with acute febrile illness in the absence of an obvious focus of infection were prospectively investigated. Blood samples were taken from all of the patients and checked for aerobic bacteria and leptospires by culture. In addition, at least two samples of serum were collected at different times (on admission and 2-4 weeks post-discharge) from each patient and tested, in serological tests, for evidence of leptospirosis, rickettsioses, dengue and influenza. The 845 patients investigated, of whom 661 were male, had a median age of 38 years and a median duration of fever, on presentation, of 3.5 days. Most (76.5%) were agricultural workers and most (68.3%) had the cause of their fever identified, as leptospirosis (36.9%), scrub typhus (19.9%), dengue infection or influenza (10.7%), murine typhus (2.8%), Rickettsia helvetica infection (1.3%), Q fever (1%), or other bacterial infection (1.2%). The serological results indicated that 103 (12.2%) and nine (1%) of the patients may have had double and triple infections, respectively. Leptospirosis and rickettsioses, especially scrub typhus, were thus found to be major causes of acute, undifferentiated fever in Thai agricultural workers.
Abstract: The pathophysiological hallmark of spotted fever group rickettsioses comprises infection of endothelial cells with subsequent infiltration of inflammatory cells. Based on its ability to promote inflammation and endothelial cell activation, we investigated the role of CD40L in African tick bite fever (ATBF), caused by Rickettsia africae, using different experimental approaches. Several significant findings were revealed. 1) Patients with ATBF (n = 15) had increased serum levels of soluble CD40 ligand (sCD40L), which decreased during follow-up. 2) These enhanced sCD40L levels seem to reflect both direct and indirect (through endothelial cell activation involving CX3CL1-related mechanisms) effects of R. africae on platelets. 3) In combination with sCD40L, R. africae promoted a procoagulant state in endothelial cells by up-regulating tissue factor and down-regulating thrombomodulin expression. 4) Although the R. africae-mediated activation of platelets involved TLR2, the combined procoagulant effects of R. africae and sCD40L on endothelial cells involved TLR4. 5) Doxycycline counteracted the combined procoagulant effects of R. africae and sCD40L on endothelial cells. Our findings suggest an inflammatory interaction between platelets and endothelial cells in ATBF, involving TLR-related mechanisms. This interaction, which includes additive effects between sCD40L and R. africae, may contribute to endothelial inflammation and hypercoagulation in this disorder.
Abstract: Rickettsia prowazekii is the causative agent of epidemic typhus and a potential bioterrorism agent. Sensitive and specific rapid assays are needed to complement existing methods of detecting this organism. We developed a real-time quantitative polymerase chain reaction assay by using a species-specific probe targeting the gltA gene. This assay, which was rapid, specific for R. prowazekii only, and sensitive (cutoff detection of 1 to 5 copies per sample), detected and directly identified R. prowazekii in blood of 12 experimentally infected mice sampled at day 3 and 6 postinfection or in naturally or experimentally infected lice. Because our assay is highly standardized and easily adaptable, it could improve epidemic typhus surveillance in public health programs, especially for countries with underdiagnosed or unrecognized human cases.
Abstract: We selected in vitro erythromycin-resistant strains of Bartonella henselae. The mutants obtained had point mutations in domain V of 23S rRNA and/or in ribosomal protein L4. One lymph node of a patient with cat-scratch disease had such a mutation in 23S rRNA, suggesting that natural resistant strains may infect humans.
Abstract: BACKGROUND: As a greater number of HIV-infected patients survive despite profound immunodepression due to medical progress, we face complex infection with multiple agents in AIDS-patients. CASE PRESENTATION: We report the case of an AIDS patient with a primary clinical presentation suggestive of bacillary angiomatosis. We also found in cutaneous lesions Mycobacterium avium complex and cytomegalovirus. CONCLUSION: This clinical case illustrates the possibility of multiple coinfections in AIDS patients and the need to be exhaustive in evaluating infectious diseases in severely immunocompromised patients.
Abstract: We report the first laboratory-confirmed human infection due to a new rickettsial genotype in India, "Candidatus Rickettsia kellyi," in a 1-year-old boy with fever and maculopapular rash. The diagnosis was made by serologic testing, polymerase chain reaction detection, and immunohistochemical testing of the organism from a skin biopsy specimen.
Abstract: The prevalences of Bartonella spp. and Rickettsia spp. were investigated using molecular methods in 77 rodent fleas collected in November 2002 by the French forces detachment in Kabul, Afghanistan. Overall, Bartonella DNA was detected in 15.5% of gerbil fleas and 40.5% of rat fleas, whereas Rickettsia felis was found in 9% of gerbil fleas. We described for the first time in this country Bartonella quintana, B. koehlerae, B. taylorii, and Rickettsia felis in fleas from the gerbil species Meriones lybicus, and B. elizabethae and B. doshiae in rat fleas. Of these, B. quintana, B. elizabethae, B. koehlerae, and R. felis are recognized human pathogens. These results emphasize the potential risk of flea-borne infections transmitted by rodents in this area, and suggest that preventive measures should be taken in the general framework of zoonoses management.
Abstract: We report microbiologic analysis of 786 lymph node biopsy specimens from patients with suspected cat-scratch disease (CSD). The specimens were examined by standard, cell culture, and molecular methods. Infectious agents were found in samples from 391 (49.7%) of 786 patients. The most commonly identified infectious agent was Bartonella henselae (245 patients, 31.2%), the agent of CSD. Mycobacteriosis was diagnosed in 54 patients (6.9%) by culture and retrospectively confirmed by using a specific real-time PCR assay. Neoplasm was diagnosed in 181 specimens suitable for histologic analysis (26.0%) from 47 patients. Moreover, 13 patients with confirmed Bartonella infections had concurrent mycobacteriosis (10 cases) or neoplasm (3 cases). A diagnosis of CSD does not eliminate a diagnosis of mycobacteriosis or neoplasm. Histologic analysis of lymph node biopsy specimens should be routinely performed because some patients might have a concurrent malignant disease or mycobacteriosis.
Abstract: A series of sudden unexpected cardiac deaths among Swedish elite orienteerers in the 1980s have resulted from the combination of infectious diseases and physical exercise. Studies in the late 1990s have pointed to Chlamydia and Barontella, which both had a high seroprevalence among Swedish elite orienteerers. We conducted a case-control study aimed to elucidate the serologic prevalence of rickettsial diseases among Danish elite orienteerers. Ticks are known as vectors for some rickettsial diseases. None of the orienteerers had a positive antibody titer against any of the tested Rickettsia despite a very high frequency of tick bites in this group.
Abstract: Ticks collected in Northern Algeria between May 2001 and November 2003 were tested by PCR for the presence of Rickettsia spp. DNA using primer amplifying gltA and OmpA genes. Three different spotted fever group rickettsias were amplified from these ticks: R. Conorii subsp. P. conorii strain Malish in Rhipicephalus sanguineus, R. aeschlimannii in Hyalomma marginatum, and R. massiliae in Rhipicephalus turanicus. Our results confirm the presence of R. conorii in ticks in Algeria and provide the first detection of R. aeschlimannii and R. massiliae in Algeria.
Abstract: Himachal Pradesh state of India is situated in the outer Himalayan ranges. During the rainy season, several cases of acute febrile illness of unknown origin occurred. Orientia tsutsugamushi was identified as the causative agent by microimmunofluorescence and PCR. Two new genotypes of O. tsutsugamushi were identified in the region.
Abstract: We provide the first evidence that Bartonella quintana can infect dogs and cause typical signs of endocarditis. Using PCR and sequencing, we identified B. quintana in the blood of a dog from the United States with aortic valve endocarditis and probably also in the mitral valve of a dog from New Zealand with endocarditis.
Abstract: After an outbreak of human plague, 95 Xenopsylla cheopis fleas from Algeria were tested for Yersinia pestis with PCR methods. Nine fleas were definitively confirmed to be infected with Y. pestis biovar orientalis. Our results demonstrate the persistence of a zoonotic focus of Y. pestis in Algeria.
Abstract: Fleas collected in Algeria in the district of Oran between July and September 2003 were tested by polymerase chain reaction for the presence of Rickettsia spp. DNA using primers amplifying gltA and OmpA genes. Two gltA sequences identical to those of an emerging pathogen, Rickettsia felis, were detected including i) R. felis California 2 in Ctenocephalides canis from rodents and ii) R. felis RF2125 in Archeopsylla erinacei from hedgehogs.
Abstract: In 2004 between the months of May-November, 11 patients with spotted fever group (SFG) rickettsioses were admitted to the Trakya University Hospital in Edirne, Turkey. SFG rickettsioses were diagnosed clinically. Before treatment, punch biopsy from skin lesions, especially from the eschar, was performed. Serum specimens were tested by IFA using a panel of nine rickettsial antigens, including SFG rickettsiae and R. typhi. Western blotting and standard PCR were also performed. The average age of the 11 patients (4 male and 7 female) was 51 years. All the patients had high fever; 10 (91%) had maculopapular rash; 8 (73%) had rash in the palms or on the soles. Five patients had a unique eschar; two had double eschars (64%). Two patients presented with multiple organ failure and one of them died. All the patients had significant antibody titers against SFG rickettsiae. PCR experiments of skin biopsies were positive in six (60%) of 10 skin biopsy samples and DNA sequencing of the positive PCR products gave 100% homology with Rickettsia conorii Malish 7 for opmA and gltA. Trakya Region in an endemic area for rickettsioses. In this series, three patients presented with life-threatening diseases and one of them died. This patient was the first fatal case (2.8%). Atypic and serous life-threatening presentations of rickettsioses must be kept in mind for the differential diagnosis of febrile disease in Turkey.
Abstract: Although Mediterranean spotted or "boutonneuse" fever (MSF) has been documented in central Tunisia, other spotted fever group rickettsioses (SFGR) and typhus group rickettsioses (TGR) have received little attention in our region. We sought to determine the role of rickettsioses, Q fever, ehrlichioses, and bartonelloses among patients with acute fever. The results of this study of 47 persons with acute fever of undetermined origin are reported in this paper. We concluded that SFGR, murine typhus, and acute Q fever are common causes of acute isolate fever in summer in central Tunisia and should be investigated systematically in patients with acute fever of unknown origin.
Abstract: The presumptive cases of Mediterranean spotted fever have been identified in 1993 and since that time, its frequency has steadily increased. The prospective study, in summer 2004, was conducted in order to present the descriptive clinic and epidemiology, to identify more severe forms, the presence of the multiple eschars, and different rickettsial strains caused the disease in our region. In Oran, the cases were diagnosed clinically. In Marseille, serum specimens were tested by IFA using the panel of eight rickettsial antigen; Western blot and cross-adsorption studies were also performed in order to confirm the diagnosis. Ninety-three patients clinically diagnosed were recorded from July 3 to October 28, 2004. Eighty percent were male, the mean age was 44.3 years, 90% were exposed to dog and 32% reported tick bites. Clinical signs were as follow: presence of underlying disease (44%), sudden onset (78%), fever (100%), loss of weight (63%), conjunctivitis (43%), and a tache noire was noticed in 70%. Interestingly, two patients had two and three eschars, respectively. The rash was maculopapular (palm and sole) and purpuric in nine cases. Doxycycline was the most antibiotic (91%) with favourable outcome in 91% of the cases. Malignant form with death is reported for three patients (3.2%). Among the 93 patients, 104 serum from 65 patients were tested (serums of others patients were lost or ticket not found on tube. Sixty-three patients out of 65 had a positive serology by IFA with cross-reactive antibodies especially between R. conorii, R. felis and/or R. typhi. Two others negative serology were: one precocious serum and second from the patient, which presented symptoms of MSF and tested two serums, Western blot and cross-adsorption.
Abstract: BACKGROUND: Q fever is a worldwide zoonosis caused by Coxiella burnetii, which can be isolated from ticks. Reports of people with both Q fever and other tickborne diseases are rare. In this study, we describe 6 patients with Q fever who were infected with 1 of the following tickborne pathogens: Rickettsia conorii (2 patients), Rickettsia slovaca (2), Rickettsia africae (1), and Francisella tularensis (1). METHODS: Diagnoses were made on the basis of results of microimmunofluorescence assays for detection of C. burnetii, R. conorii, R. slovaca, R. africae, and F. tularensis antigens. Cross-adsorption studies and Western blots were used to confirm dual infections. RESULTS: Among the 6 cases presented, 3 were probably due to a concomitant infection after a tick bite, whereas the remaining 3 were more likely consecutive infections. CONCLUSIONS: Because acute Q fever is often asymptomatic, we recommend that patients infected with the tickborne pathogens mentioned above also undergo routine testing for concurrent infections with C. burnetii.
Abstract: Bartonella quintana is a fastidious microorganism associated with blood culture negative endocarditis. In this study, 40 sera with cross-reactivity between Chlamydia species from patients from Sfax, Tunisia, were serologically tested for Bartonella. Thirteen sera were positive for Bartonella with IgG titers >/=1:800. Western blot and cross-absorption confirmed the diagnosis of Bartonella quintana endocarditis in 12 cases and Bartonella henselae endocarditis in 1 case. These sera were also positive by LightCycler nested PCR amplification for the rnpb (7 of 13) and fur (11 of 13) genes. Eleven patients had a definite diagnosis of endocarditis, which represents 9.8% of all endocarditis. Because Bartonella endocarditis seems to be very common in Tunisia, we suggest that its serology be performed systematically whenever endocarditis is suspected.
Abstract: A Japanese traveler returning from Kenya became ill, presenting with fever and a prominent, generalized rash without an eschar. Results of the immunofluorescence antibody assay of the patient's sera performed in Japan were compatible with illness due to a spotted fever group (SFG) rickettsia, and a presumptive diagnosis of African SFG rickettsiosis, probably either Mediterranean spotted fever (MSF) or African tick-bite fever (ATBF), was rendered. To further define the disease diagnosis, sera were examined in France by Western immunoblotting combined with cross-adsorption, which confirmed the diagnosis of MSF but not of ATBF. Because of the need to further characterize the epidemiologic and clinical features of the two African SFG rickettsioses, clinicians are encouraged to contact a specialized laboratory when encountering such cases.
Abstract: Although Plasmodium falciparum malaria and Q fever are both prevalent in Africa, there have been no reports of co-infection to date. We report a case who returned from the Comoros archipelago diagnosed by serologic analysis as well as detection of Coxiella burnetii DNA in acute-phase serum. Thus, Q fever may be associated with malaria infection in travelers returning from disease-endemic countries. This diagnosis should be considered when the response to malaria treatment is incomplete.
Abstract: We detected Rickettsia felis DNA in Ctenocephalides felis and Bartonella quintana DNA in 3 Pulex irritans fleas taken from a pet Cercopithecus cephus monkey in Gabon, sub-Saharan Africa. This is the first report of B. quintana in the human flea.
Abstract: In this study we describe molecular mechanisms of resistance to several classes of antibiotics within drug targets by in silico genome comparisons for bacteria of the genus Rickettsia. Apart from the mutations in the rpoB gene in naturally rifampin-resistant Rickettsia species previously reported by our team, we found that typhus group (TG) rickettsiae had a triple amino acid difference in the highly conserved region of the L22 ribosomal protein as compared to the spotted fever group rickettsiae (SFG), which could explain the natural resistance of SFG rickettsia to erythromycin. We found also that the genome of R. conorii contains an aminoglycoside 3'-phosphotransferase. Finally, either folA gene (encoding dihydrofolate reductase) and/or folP gene (encoding dihydropteroate synthase) was missing in the genome of rickettsial strains explaining the natural resistance to cotrimoxazole. Finally, multiple genes encoding for pump efflux were found especially in the genome of R. conorii that could be involved in resistance to antibiotics. Five specific ORFs related to antibiotic resistance have been identified in the genome of R. felis including a streptomycin resistance protein homologue, a class C beta-lactamase, a class D beta-lactamase, a penicillin acylase homologue, and an ABC-type multidrug transporter system. For the first time, using this approach, an experimental beta-lactamase activity has been shown for this bacterium. We believe that whole genome sequence analysis may help to predict several phenotypic characters, in particular resistance to antibiotics for obligate intracellular bacteria.
Abstract: Between 4 May and 8 August 2002,46 cases of acute fever were reported near the Black Sea region in northern Turkey. The infection was treated rapidly and successfully with tetracyclines, so clinical diagnosis of rickettsial or ehrlichial infection was considered. Analysis of serum and blood samples taken from 19 patients identified the causative organism as Coxiella burnetii; 7 cases were reported as acute Q fever and 8 as seropositive for past infection. The most common clinical symptoms among the acute cases were vomiting (100.0%), nausea (85.7%), diarrhoea (57.1%), fever (42.9%), abdominal pain (42.9%) and headache (42.9%). Liver enzymes were elevated in all patients. It is considered that epidemiological investigation for Q fever will be essential in the affected region in future.
Abstract: In this study we have evaluated the in vitro activity of antibiotics against 13 new isolates of Coxiella burnetii using a real-time quantitative PCR assay. MICs against doxycycline ranged from 1 to 8 microg/mL, telithromycin from 0.5 to 2 microg/mL, and all strains had MICs > or = 8 microg/mL for erythromycin. We report that strains resistant to doxycycline exist either in humans or animals.
Abstract: AIMS: To provide further information on the prevalence of Rickettsia felis, Bartonella hensela, and B. clarridgeiae in cat and dog fleas in New Zealand and their distribution in the country. METHODS: We used PCR and sequencing with primers for the its and pap 31 (for Bartonella spp.), and the gltA and OmpB (for Rickettsia spp.) genes on DNA from fleas collected from dogs and cats presenting to 3 widely separated veterinary practices on the North Island. RESULTS: DNA of R. felis (19%), B. henselae (11%), and B. clarridgeiae (7%) was found in the 114 cat fleas (Ctenocephalides felis) we studied. The DNA of both B. henselae and B. clarridgeiae was found in 3 fleas (from 2 animals); B. clarridgeiae and R. felis in 1 flea; B. henselae and R. felis in 5 fleas (from 3 animals); and R. felis, B. henselae, and B. clarridgeiae in 2 fleas (from 1 animal). No amplicons were obtained from 3 dog fleas (Ctenocephalides canis). CONCLUSIONS: The emerging human pathogens, R. felis, B. henselae, and B. clarridgeiae, are prevalent and widely distributed in cat fleas in the North Island of New Zealand.
Abstract: Endocarditis is the major clinical manifestation of chronic Q fever. Although doxycycline along with hydroxychloroquine remains the mainstay of medical therapy for Q fever endocarditis, there are wide variations in the rapidity of the patient's decline of antibody levels during such therapy. We undertook a retrospective examination of whether there was any correlation between the ratio of serum concentration to MIC of doxycycline and response to treatment in patients with Q fever endocarditis. Included herein are 16 patients from whom Coxiella burnetii was isolated from cardiac valve materials. Serology and measurement of doxycycline and hydroxychloroquine serum levels were performed and recorded after 1 year of treatment. The MIC of doxycycline for C. burnetii isolates was determined using the shell vial assay in a real-time quantitative PCR assay. At the completion of a year-long therapy with doxycycline-hydroxychloroquine, all those that showed a low decline of antibody levels (n = 6) (i.e., <2-fold decrease in antibody titer to phase I C. burnetii antigen) had a ratio of serum doxycycline concentration to MIC between 0.5 and 1. In contrast, those having a ratio of > or =1 showed a rapid decline of phase I antibody levels (n = 9; P < 0.05). The only patient who died had a serum doxycycline-to-MIC ratio of <0.5, and the isolate of C. burnetii cultured from this patient was resistant to doxycycline (MIC = 8 microg/ml). The ratio of serum doxycycline concentration to MIC should be monitored during the course of therapy in patients with Q fever endocarditis.
Abstract: OBJECTIVES AND METHODS: Whipple's disease is a rare multisystem chronic infection, involving the intestinal tract as well as various other organs. Tropheryma whipplei is a slow-growing facultative intracellular bacterium that remains poorly understood. In vitro antibiotic susceptibility testing has previously been assessed in cells using a real-time quantitative PCR assay. In this study, we have evaluated the antibiotic susceptibility of three strains of T. whipplei grown in axenic medium using the same assay. RESULTS: The active compounds in axenic medium were doxycycline, macrolide compounds, penicillin G, streptomycin, rifampicin, chloramphenicol, thiamphenicol, teicoplanin, vancomycin, amoxicillin, gentamicin, aztreonam, levofloxacin and ceftriaxone, with MICs in the range 0.06-1 mg/L. Cefalothin was less active, with MICs in the range 2-4 mg/L. We found that co-trimoxazole was active with MICs in the range 0.5-1 mg/L, and sulfamethoxazole alone was active with MICs in the range 0.5-1 mg/L. MICs of trimethoprim varied from 64-128 mg/L. CONCLUSIONS: Co-trimoxazole was effective in vitro, but this activity was due to sulfamethoxazole alone. These results were in accordance with the fact that T. whipplei does not contain the encoding gene for dihydrofolate reductase, the target for trimethoprim.
Abstract: OBJECTIVES: Typhus group (TG) rickettsiae are naturally susceptible to erythromycin whereas spotted fever group (SFG) rickettsioses are not. The aim of this study was to compare in silico genetic determinants known to be associated with resistance to macrolide compounds. METHODS AND RESULTS: Available sequences of the 23S RNA gene, and L4 and L22 ribosomal proteins of rickettsial strains were aligned and compared using in silico methods. Although there were no sequence differences in domain V of the 23S RNA gene and in the conserved region of the L4 ribosomal protein gene, we found that TG rickettsiae had a triple amino acid difference in the highly conserved region of the L22 ribosomal protein compared with the SFG rickettsiae. CONCLUSIONS: We believe that the triple amino acid difference in the L22 ribosomal protein found in this study may explain the difference in susceptibility to erythromycin among the Rickettsia genus. Genome analysis may help to predict possible molecular mechanisms of resistance for fastidious and intracellular bacteria and cloning and expression of such proteins should be investigated in the future in order to prove our hypothesis.
Abstract: Lobular capillary hemangioma and bacillary angiomatosis due to Bartonella infection share several clinical and histopathologic characteristics. We sought to determine whether lobular capillary hemangioma is caused by the same agent as bacillary angiomatosis. Forty-five pathology specimens with a histologic diagnosis of lobular capillary hemangioma obtained from patients with the same clinical diagnosis were tested by immunohistochemistry and polymerase chain reaction for the presence of DNA elements of Bartonella spp. None of the 45 lobular capillary hemangioma specimens tested positive for Bartonella spp. We conclude that lobular capillary hemangioma is not associated with Bartonella spp infection. Further research is required to determine the etiologic agent.
Abstract: INTRODUCTION: Propionibacterium acnes is a gram-positive pleomorphic rod-shaped anaerobic saprophyte of the skin, mouth and upper respiratory tract. Although associated with acne vulgaris, it is otherwise reported as a human pathogen only rarely, in various infections, notably cutaneous and osteoarticular, and in endocarditis. We report here a case of bilateral P. acnes-abscessed adenitis of the inguinal folds. CASE: A 32 year-old man presented with inguinal lymph nodes that had progressively and bilaterally reddened and become painful, with fistulation of the skin and pus. Culture of a surgical sample identified P. acnes. DISCUSSION: Although this strain has been associated with lymph node granuloma, especially in sarcoidosis, abscessed lymph node infection as seen in our patient has never been reported.
Abstract: Homeless people are particularly exposed to ectoparasites, but their exposure to arthropod-borne diseases has not been evaluated systematically. A medical team of 27 persons (7 nurses, 6 infectious disease residents or fellows, 2 dermatologists, and 12 infectious disease specialists) visited the 2 shelters in Marseilles, France, for 4 consecutive years. Homeless volunteers were interviewed, examined, and received care; and blood was sampled for cell counts and detection of bacteremia, antibodies to louse-borne (Rickettsia prowazekii, Bartonella quintana, and Borrelia recurrentis), flea-borne (R. typhi, R. felis), mite-borne (R. akari), and tick-borne (R. conorii) bacterial agents. We selected sex- and age-adjusted controls among healthy blood donors. Over 4 years, 930 homeless people were enrolled. Lice were found in 22% and were associated with hypereosinophilia (odds ratio, 5.7; 95% confidence intervals, 1.46-22.15). Twenty-seven patients (3%) with scabies were treated with ivermectin. Bartonella quintana was isolated from blood culture in 50 patients (5.3%), 36 of whom were treated effectively. The number of bacteremic patient increased from 3.4% to 8.4% (p = 0.02) over the 4 years of the study. We detected a higher seroprevalence to Borrelia recurrentis, R. conorii, and R. prowazekii antibodies in the homeless. Our study shows a high prevalence of louse-borne infections in the homeless and a high degree of exposure to tick-borne diseases and scabies. Despite effective treatment for Bartonella quintana bacteremia and the efforts made to delouse this population, Bartonella quintana remains endemic, and we found hallmarks of epidemic typhus and relapsing fever. The uncontrolled louse infestation of this population should alert the community to the possibility of severe re-emerging louse-borne infections.
Abstract: In the Trakya region of Turkey, located in the European part of the country, presumptive cases of Mediterranean spotted fever have been diagnosed and treated every summer since the beginning of the 1990s. The aim of this prospective study was to isolate and identify the rickettsial strains from blood samples of 11 patients and from skin biopsies of 10 of these 11 patients with the diagnosis of spotted fever in the Trakya region of Turkey in 2003. Immunofluorescence assay was performed with acute-phase and convalescent-phase serum samples of 11 patients. All patients had significant antibody titers against spotted fever group rickettsiae. Rickettsia conorii was isolated from the skin biopsies of three of ten patients and was also demonstrated by polymerase chain reaction in skin biopsies of nine of ten patients. In southeastern Europe, the Balkan Peninsula (including the Trakya region of Turkey) is an area where arthropods are endemic and where new arthropod-borne infections can be detected.
Abstract: Between the dates of May 4th-August 6th 2002, 46 cases were detected with abdominal pain nausea, vomiting, arthralgia/myalgia, headache, fever, diarrhea and rash, in the middle Blacksea and north inner Anatolia regions. Their laboratory findings yielded elevated levels of liver enzymes (AST, ALT, LDH), leucopenia and thrombocytopenia. As the infection was treated easily with tetracyclines, clinical diagnosis was considered to be rickettsiosis or ehrlichiosis. Serum and blood samples obtained from some of the patients were tested against Rickettsia, Ehrlichia, Leptospira and Coxiella, in the national and international laboratories. Samples from 19 patients were sent to National Reference Centre and WHO Collaborating Centre for Rickettsial Reference and Research Laboratory, France, and 7 of them were reported as acute Q fever while 8 of them were reported as passed Q fever (QF) cases. In May 2003, new cases with similar symptoms have been reported from the same regions, with different epidemiologic and serologic findings (tick exposure history was higher, response to tetracycline was lower, C. burnetii antibodies were negative), indicating a viral etiology. The samples of these patients have been sent to National Reference Centre and WHO Collaborating Centre for Arboviruses and Viral Heamorrhagic Fevers, France, and the initial reports were marked as Crimean Congo hemorrhagic fever virus (CCHFV). Then the serum samples of previous 26 patients which were stored in National Serum Bank have been retrospectively investigated for viral aetiology in the same center, and 17 of them have been found positive for CCHFV IgM antibodies. Four of these patients were diagnosed as acute QF in 2002, one was passed QF, 2 were negative for QF and 10 were patients not investigated for QF. As a result, the detection of the both infections together in the same area shows the essential need for further epidemiological investigations.
Abstract: OBJECTIVES: Determination of bacterial antimicrobial susceptibility is usually performed using phenotypic methods. In this study, we developed a universal 16S rRNA and rpoB quantitative PCR assay for susceptibility testing of bacteria commonly isolated in clinical microbiology laboratories. METHODS: Antibiotic susceptibilities for 24 bacterial strains of various species were tested by real-time quantitative PCR assay and by conventional methods. Quantification of DNA copies of either the 16S RNA genes or rpoB were recorded over time in the presence or absence of antibiotics to determine the bacterial growth kinetics and the optimal testing time. RESULTS: Molecular results for antibiotic susceptibility or resistance were in accordance with those obtained using a standard macrodilution broth assay. The method was reproducible, sensitive and rapid (2 h for Gram-negative bacilli and 4 h for Gram-positive cocci). Moreover, this assay was also able to determine the antibiotic susceptibilities of fastidious bacteria, such as mycobacteria, within 5 days. CONCLUSIONS: These results demonstrate that molecular detection of bacteria could be more rapid than phenotypic methods for antibiotic susceptibility testing.
Abstract: PURPOSE OF REVIEW: Recent developments in cell-culture techniques and molecular methods have led to the description of several new rickettsial diseases. An update on these new infections should be of interest to health workers with patients who are international travellers. RECENT FINDINGS: Epidemic typhus was reported last year in the United States when an outbreak of murine typhus was recorded in Hawaii. Among spotted fever group rickettsioses, African tick bite fever is now probably the most common rickettsial infection in Africa with numerous cases also reported in international travellers. For the first time the Astrakhan fever rickettsia has been described outside Europe, in a French patient returning from Chad. Similarly, the first case of Rickettsia sibirica mongolotimonae infection in Africa was reported in 2004. Finally, a newly recognized agent of a spotted fever rickettsiosis, Rickettsia parkeri, has been reported in the United States during 2004. SUMMARY: Because results of serological testing are only presumptive, sophisticated methods are crucial for the diagnosis and description of new rickettsial diseases, especially in atypical cases. Modern diagnostic tools include cross-adsorption assays, Western blot testing, and cell-culture and molecular-biological methods.
Abstract: In the 1990s, studies were conducted to investigate 16 episodes of sudden unexpected cardiac death (SUCD) among Swedish elite orienteers during the period from 1979 to 1992. A case control study revealed that a significantly higher proportion of Swedish elite orienteers were B. elizabethae seropositive compared to controls. The aim of our study, designed as a case-control study, was to determine whether similarly high rates of B. elizabethae seropositivity were present among Danish elite orienteers. Cases were 43 elite orienteers; controls were 159 blood donors and 63 elite indoor sportsmen. All participants were tested for antibodies against B. henselae, B. quintana and B. elizabethae using immunofluorescent antibody tests. Surprisingly, Bartonella antibodies were only detected in sera from 5 persons: B. henselae from 1 elite orienteer, 1 handball player and 1 blood donor. B. elizabethae antibodies were detected in 1 handball player and 1 basketball player. We found no association between elite orienteers and the prevalence of Bartonella antibody positivity. This is in contrast to the Swedish study, and might be explained by the use of different serological methods in the 2 studies; to determine whether it is a true difference, a new study is needed.
Abstract: Whipple's disease is considered a rare chronic disease with a broad spectrum of clinical manifestations. Several antibiotics have been used for the treatment of this disease, and the current reference treatment was determined empirically on the basis of only a few clinical observations. Patients should be treated for months, and many relapse after antibiotic withdrawal. We report here the first extensive study on the susceptibilities of three reference strains of Tropheryma whipplei to antibiotic in cell culture by using a real-time PCR assay as previously described. We found that doxycycline, macrolides, ketolides, aminoglygosides, penicillin, rifampin, teicoplanin, chloramphenicol, and trimethoprim-sulfamethoxazole were active, with MICs ranging from 0.25 to 2 microg/ml. Vancomycin was somewhat active at an MIC of 10 microg/ml. We found heterogeneity in the susceptibility to imipenem, with one strain being susceptible and the two other strains being resistant. Cephalosporins, colimycine, aztreonam, and fluoroquinolones were not active. We also demonstrated that a combination of doxycycline and hydroxychloroquine was bactericidal. This combination has been shown to be active in the treatment of patients suffering from chronic infections with Coxiella burnetii, a bacterium that is also found intracellularly in acidic vacuoles. We believe, then, that this combination therapy should be further evaluated in clinical trials for the treatment of Whipple's disease.
Abstract: We report a case of Bartonella quintana acute symptomatic infection in a homeless man, presenting as a typical trench fever. B. quintana has been retrieved in erythrocytes in large clusters and in erythroblasts. Direct immunofluorescence of blood smears allows a rapid diagnosis.
Abstract: We determined MICs of antibiotics against Anaplasma phagocytophilum, Ehrlichia chaffeensis, and Ehrlichia canis by real-time quantitative PCR. The doubling times of the organisms were established: 19 h for E. chaffeensis, 26 h for A. phagocytophilum, and 28 h for E. canis. In comparison to the reference method for determining sensitivities, which uses Diff-Quick staining, our PCR assay was very sensitive and specific. We confirmed that doxycycline and rifampin are highly active against these bacteria and found variable susceptibilities to fluoroquinolones; A. phagocytophilum was susceptible, but E. canis and E. chaffeensis were only partly susceptible. Beta-lactam compounds, cotrimoxazole, macrolide compounds, and telithromycin showed no activity against any of the three organisms. Thiamphenicol was found to be more active than chloramphenicol. For the first time, we showed that these three species have numerous point mutations in their 23S RNA genes, with those at positions 754, 2057, 2058, 2059, and 2611 (Escherichia coli numbering) known to confer resistance to macrolide compounds in other bacteria. The role of each of these mutations in resistance to these drugs should be investigated in the future. Our study confirms previous reports that quantitative PCR is a reliable method for determining antibiotic susceptibility; therefore, it might be useful for screening new drugs.
Abstract: The prevalence of Bartonella infection in a pet cat population from France was found to be 8.1% (8 of 99 cats). The intraerythrocytic location of Bartonella clarridgeiae is shown for the first time, and we show that immunofluorescence detection of the organism in erythrocytes correlates with the number of bacteria in blood.
Abstract: The objective of this study was to determine MICs of antibiotics for two reference strains of Coxiella burnetii using real time quantitative PCR. The method was very sensitive and specific and allowed the evaluation of the doubling time of Nine Mile and Q212 strains: 37 and 15 h, respectively. Dose response curves of antibiotics were used to determine MICs. Those of doxycycline, fluoroquinolone compounds and rifampicin were in the range 1-4 mg/l. Telithromycin was the most effective macrolide compound with MICs of 1-2 mg/l. The results confirmed previous reports on the accuracy of this new method for the determination of the antibiotic susceptibility of C. burnetii and could be used for the screening of new drugs.
Abstract: We tested a single-step serological assay against Coxiella burnetii and Bartonella species and found a sensitivity of 100%, and a positive predictive value of 98% for the diagnosis of blood culture-negative endocarditis (BCNE). This assay should be considered as a possible commercial test for the diagnosis of BCNE.
Abstract: The recommended treatment for Q fever endocarditis is a combination of doxycycline and hydroxychloroquine. We found a correlation between serum doxycycline concentrations and decreases in levels of phase 1 Coxiella burnetii antibodies, in 24 patients with Q fever endocarditis. Patients who had a >2-fold decrease in levels of phase 1 antibodies had serum doxycycline concentrations higher than those of the other patients (mean+/-SD, 5.29+/-1.75 vs. 3.14+/-1.40 microg/mL; P=.003). We recommend adjusting the posology of doxycycline to achieve a serum concentration of at least 5 microg/mL.
Abstract: A 50-year-old man was admitted with a liver abscess and positive serology for Brucella spp. Liver pus and blood cultures remained sterile on conventional culture. Inoculation of liver pus onto eukaryotic cells by the centrifugation-shell vial technique yielded Brucella melitensis, identified by 16S rRNA gene amplification and sequencing.
Abstract: Scrub typhus, caused by Orientia tsutsugamushi, is a rural zoonosis endemic in the Asian Pacific region. Doxycycline and chloramphenicol, the recommended drugs for treating this infection, may not be safe during pregnancy. We report on 5 patients with scrub typhus during pregnancy who were seen in India between October 2001 and February 2002. Four of the 5 women were treated initially with ciprofloxacin. Three women had stillbirths, 1 an abortion and 1 a low birthweight baby, which suggests that ciprofloxacin should not be used for treating pregnant women and that scrub typhus leads to severe adverse effects during pregnancy. Randomized controlled trials are urgently needed to ascertain the optimal drug choice, given that currently recommended drugs are contraindicated in pregnant women.
Abstract: The prevalences of Bartonella, Rickettsia, and Wolbachia were investigated in 309 cat fleas from France by polymerase chain reaction (PCR) assay and sequencing with primers derived from the gltA gene for Rickettsia, the its and pap31 genes for Bartonella, and the 16S rRNA gene for Anaplasmataceae. Positive PCR results were confirmed by using the Lightcycler and specific primers for the rOmpB of Rickettsia and gltA of Bartonella. R. felis was detected in 25 fleas (8.1%), W. pipientis, an insect symbiont, in 55 (17.8%), and Bartonella in 81 (26.2%), including B. henselae (9/81; 11.1%), B. clarridgeiae (55/81; 67.9%), B. quintana (14/81; 17.3%), and B. koehlerae (3/81; 3.7%). This is the first report of the amplification of B. quintana from fleas and the first description of B. koehlerae in fleas from an area outside the United States. Cat fleas may be more important vectors of human diseases than previously reported.
Abstract: In this report we describe a 30-year old male patient with vertebral osteomyelitis and spleen abscesses with cat scratch disease. The diagnosis was made on the basis of molecular detection of Bartonella henselae either on lymph node biopsies or on bone biopsy, histology of the lymph node, serology using either our in-house microimmunofluorescence assay or a commercial kit (Focus Technologies). Immunofluorescent detection was also performed directly on slide appositions using a monoclonal antibody. Treatment consisted of administration of antibiotics with rapid clinical improvement and a stabilization of skeletal lesions on the magnetic resonance imaging performed three months later. Twenty two other cases of this unusual manifestation associated with cat scratch disease have been reported in the literature and are reviewed here. Our case represents the second case of osteomyelitis associated with cat scratch disease in which B. henselae has been specifically identified as the etiological agent using several direct and indirect methods.
Abstract: Orientia tsutsugamushi, the agent of scrub typhus, is a strict intracellular bacterium which is found in many parts of Asia including India. During the past few years, the number of patients with rickettsial infection and scrub typhus has increased, especially during the cooler months. We report in this study a recent outbreak of scrub typhus recorded during the cooler months (October 2001 to February 2002) in patients admitted to our hospital with acute febrile illness associated with diverse signs and symptoms. Overall, 28 patients were clinically and serologically confirmed to have scrub typhus. Fever for more than one week was the only common manifestation. Myalgias was the next most common feature (52%), and rash was observed in only 22% of the cases. Seventeen patients treated with doxycycline recovered in 1 to 3 days, as well as two patients who received chloramphenicol. In five patients who received ciprofloxacin, fever subsided only after five days. Finally three patients (10.7%) died, including one patient treated with doxycycline. These data indicate that scrub typhus is a reemerging infectious disease in India with a possibility of drug resistance. This reemergence emphasizes the need for further prospective studies to design effective control measures.
Abstract: Bartonella spp. are found in the erythrocytes of their specific natural hosts and B. quintana bacteremia is associated epidemiologically with lice, alcoholism, and homelessness. The aim of our study was to compare the growth and the number of bacteria per erythrocyte in vitro in laboratory-infected red blood cells from alcoholic patients versus normal blood donor erythrocytes. Enumeration of bacteria was performed either with plate counting or with a real-time PCR quantitative assay. Number of bacteria per cell was determined using immunofluorescence assay and laser confocal microscopy. Although the number of bacteria after 4 days of incubation was similar in the two groups of erythrocytes, we found that the distribution of bacteria per erythrocyte in the two groups was different. Erythrocytes from alcoholics contain significantly more bacteria per cell than erythrocytes from blood donors. Our results suggest that there is a link between alcoholism and infections of B. quintana that may be due to the macrocytosis of erythrocytes.
Abstract: In 2000, Q fever was documented for the first time in the Sultanate of Oman in two patients, one with chronic pericarditis and the other with acute pneumonia. In 2001, a study of a randomly selected group of 102 adult patients from different provinces in northern Oman, presenting to the University Hospital in Muscat with unrelated conditions (e.g., diabetes mellitus, ischemic heart disease), revealed that 10 (9.8%) were seropositive for previous Coxiella burnetii infection. Examination of sera from a randomly selected group of 54 healthy goats from eight different herds from three different provinces of Oman, obtained by the Veterinary Research Center in Muscat, revealed that 28 (52%) had been infected, and 5 sheep, each from one of four herds, were seropositive for C. burnetii. We suspect that Q fever is widely prevalent in human populations in Oman, and that infection is widespread in goat, and probably sheep and other livestock populations, throughout the country.
Abstract: Q fever is a worldwide-occurring zoonosis caused by Coxiella burnetii. There are various clinical manifestations of acute Q fever, of which acute cholecystitis is a very rare clinical presentation. This study reports seven cases of acute cholecystitis associated with Coxiella burnetii and reviews two other cases from the literature. All patients were admitted to hospital for fever and abdominal pain in the right upper quadrant. Abdominal echography showed a distended gallbladder with biliary sludge without concrements in eight cases and with a single stone in one case. Diagnosis was made by specific serological investigation (microimmunofluorescence assay) for Coxiella burnetii. All nine patients were cured, six after laparoscopic cholecystectomy and three with antibiotics only. Histological examination of the gallbladders showed inflammation in five cases, although Coxiella burnetii was not detected by immunohistochemistry. The results show that laboratory investigations in patients admitted to hospital for symptoms consistent with acute acalculous cholecystitis should include a systematic search for Coxiella burnetii.
Abstract: OBJECTIVE: To determine whether disinfection protocols currently used for gastroscopes are effective against cultures of Tropheryma whipplei. DESIGN: The bactericidal activity of 2% glutaraldehyde and two peracetic acids on the Twist-Marseille strain of T. whipplei grown in cell monolayers was determined. PATIENTS: Two patients who were diagnosed as having Whipple's disease 3 years after they had had intestinal biopsies. RESULTS: The disinfectants reduced bacteria by approximately 2 log to 3 log10 after 5 to 60 minutes of contact. CONCLUSION: The bactericidal activity of a disinfectant is usually considered significant if it causes a 5 log10 or greater reduction in viable bacterial titers. Disinfecting gastroscopes with 2% glutaraldehyde or peracetic acids for 20 minutes may be insufficient to prevent transmission of T. whipplei on the instruments or stop false-positive results on polymerase chain reaction.
Abstract: Tropheryma whipplei, the agent of Whipple's disease, grows fastidiously only in cell cultures without plaque production, and only three strains have been passaged. The formation of bacterial clumps in the supernatant precludes enumeration of viable bacteria and MIC determination. We evaluated the bacteriostatic effects of fluoroquinolones against two T. whipplei isolates by measuring the inhibition of the DNA copy number increase by real-time quantitative PCR. The analysis of the T. whipplei genome database allowed the identification not only of the gyrA gene but also the parC gene encoding the alpha subunit of the natural fluoroquinolone targets DNA gyrase (GyrA) and topoisomerase IV (ParC), respectively. The parC gene was detected in actinobacteria for the first time. High ciprofloxacin MICs (4 and 8 micro g/ml) were correlated with the presence in T. whipplei GyrA and ParC sequences with an alanine residue at positions 83 and 80 (Escherichia coli numbering), respectively. Alanines at these positions have previously been associated with increased fluoroquinolone resistance in E. coli and mycobacteria. However, the MIC of levofloxacin was low (0.25 micro g/ml). The same T. whipplei GyrA and ParC sequences were found in two other cultured strains and in nine uncultured tissue samples from Whipple's disease patients, allowing one to speculate that T. whipplei is naturally relatively resistant to fluoroquinolones.
Abstract: To investigate the presence of rickettsioses in rural residents of the central Thai-Myanmar border, we tested the blood of 46 patients with fever. Four patients had murine typhus, three patients had scrub typhus, and eight patients had spotted fever group rickettsioses, including the first case of Rickettsia felis infection reported in Asia.
Abstract: Astrakhan fever is a summer spotted fever resembling Mediterranean spotted fever, endemic in Astrakhan, a region of Russia located by the Caspian sea. Its agent is a spotted fever group rickettsia, member of the Rickettsia conorii complex, transmitted to humans by Rhipicephalus sanguineus and Rhipicephalus pumilio ticks. In Summer 2001, French United Nations troops in Kosovo collected 2 ticks on asymptomatic soldiers (1 R. sanguineus and 1 Hyalomma marginatum) and 10 ticks on dogs (7 R. sanguineus, 2 Ixodes ricinus, and 1 H. marginatum) in the Morina region. By PCR amplification of both the gltA and ompA genes, we detected a rickettsia in 4 R. sanguineus, i.e., 3 of those collected on dogs and those taken from military personnel. As ticks were preserved in alcohol, culture was not possible. The sequences obtained from these PCR products identified, with a 100% homology, Astrakhan fever rickettsia. None of the other collected tick species was positive. The patient with the positive tick remained asymptomatic. Our study demonstrates, for the first time, the presence of Astrakhan fever rickettsia in ticks outside Russia. We suspect that the area of distribution of this rickettsia could be wider than initially suspected. Moreover, as R. sanguineus ticks bite humans, Astrakhan fever might be a cause of spotted fever in Kosovo.
Abstract: Laboratory diagnosis of Bartonella henselae infections can be accomplished by serology or PCR assay on biopsy samples. The purpose of our work was to assess immunofluorescence detection (IFD) in lymph node smears using a specific monoclonal antibody directed against B. henselae and a commercial serology assay (IFA) compared with PCR detection. Among 200 lymph nodes examined from immunocompetent patients, 54 were positive for B. henselae by PCR, of which 43 were also positive by IFD. Among the 146 PCR-negative lymph nodes, 11 were positive by IFD. Based on PCR results, the specificity of this new technique was 92.5%, the sensitivity was 79.6%, and the positive predictive value was 79.6%. At a cutoff titer of 64, the sensitivity of the IFA was 86.8% and the specificity was 74.1%. Diagnosis of cat scratch disease (CSD) may be improved, with a specificity of 100%, when the two tests (IFD and IFA) were negative; the sensitivity was 97.4% if one of the two tests was positive. Since PCR-based detection with biopsy samples is available only in reference laboratories, we suggest using IFD coupled with the commercial serology test for the diagnosis of CSD.
Abstract: Bartonella quintana, the agent of trench fever, has recently been implicated in various diseases, in particular, bacteremia and endocarditis in homeless people. The host cell of Bartonella spp. is believed to be the erythrocyte, and in the present study we demonstrate that B. quintana can be cultured in vitro in human erythrocytes. The bacteria were found to be intraerythrocytic by laser confocal microscopy with Bartonella species-specific monoclonal antibodies. Infections with B. quintana decreased the life span of erythrocytes in culture from 8.6 to 4.8 days. In the culture system we found that most of the antibiotics that we tested (doxycycline, fluoroquinolone compounds, and beta-lactams) were not bactericidal. Gentamicin was bactericidal at 4 micro g/ml, as was rifampin, but to a lesser extent. At this concentration, gentamicin has been shown to enter erythrocytes slowly and to reach a peak level of 0.26 micro g/ml after 24 h. At 0.26 micro g/ml, however, we found that gentamicin was not able to kill extracellular B. quintana, even after 96 h of incubation. We hypothesize that erythrocytes may be a reservoir for B. quintana and that the bactericidal activity of gentamicin that we observed occurs mainly when the bacteria emerge from the erythrocytes and are found extracellularly. It would appear that gentamicin should be administered for at least 5 days to cure patients infected with B. quintana.
Abstract: Bartonella quintana is transmitted by body lice among homeless people. Infection with this organism leads to chronic bacteraemia with few symptoms. We looked for B quintana in erythrocytes in a population of homeless people in Marseille, France. In this report we show the intraerythrocytic presence of B quintana in people with symptomless bacteraemia, by use of a specific monoclonal antibody and laser confocal microscopy. Presence of at least 5 x 10(4) colony-forming units per mL was predictive of intracellular infection. However, such infection was not associated with evidence of haemolysis. Colonisation of erythrocytes could allow efficient transmission of B quintana by body lice.
Abstract: The present study was undertaken to explore the antimalarial effect of a series of dicatecholate iron chelators. They may be made more or less lipophilic by increasing or reducing the length of the R substituent on the nitrogen. In vitro activity against the W2 and 3D7 clones of Plasmodium falciparum, toxicity on Vero cells and toxicity on uninfected erythrocytes by measure of the released haemoglobin were assessed for each compound. These findings were compared with the ability of iron(III), iron(II) and ferritin to reverse the inhibitory effect of catecholates. This study shows that increased lipid solubility of catecholate iron chelators does not lead to improved antimalarial activity. However, their activity is well correlated with their interaction with iron and with their toxicity against Vero cells. This study demonstrates a potent antimalarial effect of FR160 (R = C9H19) on five different strains of P. falciparum in vitro. FR160 inhibited parasite growth with an IC50 between 0.8 and 1.5 micro M. The effects of FR160 on mammalian cells were minimal compared with those obtained with malaria parasites. FR160 acted on parasites at considerably higher rates than desferrioxamine, and at all stages of parasite growth. The drug was more effective at the late trophozoite and young schizont stages, although FR160 affected rings and schizonts as well. Ascorbic acid, a free radical scavenger, reduced the activities of FR160 and artesunate. FR160 might induce formation of free radicals, which could explain why FR160 antagonized the effects of artesunate and dihydroartemisinin.
Abstract: Rickettsiae grow only intracellularly, and the antibiotic susceptibilities of these bacteria have been assessed by either plaque, dye uptake, or immunofluorescence assays, which are time-consuming. We used a quantitative PCR (with the LightCycler instrument) to assess the levels of inhibition of Rickettisa felis, R. conorii, and R. typhi DNA synthesis in the presence of various antibiotics. We established the kinetics of rickettsial DNA during growth and showed that R. conorii grows more quickly than R. typhi in cell culture, with maximum replication occurring after 5 and 7 days, respectively. The MICs of the antibiotics tested for R. conorii and R. typhi by the quantitative PCR assay were similar to those previously obtained by plaque and dye uptake assays. We found that R. felis is susceptible to doxycycline, rifampin, thiamphenicol, and fluoroquinolones but not to gentamicin, erythromycin, amoxicillin, or trimethoprim-sulfamethoxazole. The resistance of this new species to erythromycin is consistent with its current taxonomic position within the spotted fever group. We believe that quantitative PCR could be used in the future to simplify and shorten antibiotic susceptibility assays of other rickettsiae and other strict intracellular pathogens.
Abstract: We compared the sensitivities and specificities of indirect fluorescent antibody tests developed in our laboratory and commercially available from Focus Technologies (FT; formerly MRL Diagnostic) for detection of serum antibodies to Bartonella spp. Serum samples tested were from patients with culture- or PCR-confirmed Bartonella quintana or B. henselae infections causing cat scratch disease (CSD), chronic bacteremia, or endocarditis. At a cutoff titer of 64, the FT test had higher sensitivity than our in-house test in detecting anti-B. henselae immunoglobulin G (IgG) antibodies in CSD patients (91.2 versus 52.9%; P < 0.001). The specificity in serum samples from 85 control patients was, however, lower with the FT test (87%) than with the in-house test (98.8%) (P = 0.002). A cutoff titer of 128 improves the specificity for the FT test but lowers the sensitivity to 85%. For patients infected with B. henselae, our in-house test, but not the FT test, enabled endocarditis to be detected more reliably. With the in-house test, titers of IgG against B. henselae of >/=1,024 were found only in endocarditis patients and not in CSD patients. With the FT test, 19.1% of CSD patients had titers of IgG against B. henselae of >/=1,024 (P < 0.001). Our in-house technique also improved detection of anti-B. quintana antibodies in homeless patients with endocarditis. IgG titers of >/=1,024 were present in 75% of serum samples, but only in 16.7% of serum samples with the FT test (P = 0.004). Since each test has advantages over the other, the serological diagnosis of Bartonella infections would benefit if both tests were used concurrently.
Abstract: On the basis of phenotypic data obtained on the strain Marseille-URRWFXCal2(T), isolated from the cat flea Ctenocephalides felis, the description of Rickettsia felis (Bouyer et al., 2001) is emended and Marseille-URRWFXCal2(T) is proposed as the type strain of the species. On the basis of polyphasic characterization, especially the inability to grow at temperatures higher than 32 degrees C on Vero cells that allow growth of other Rickettsia to at least 35 degrees C, it is confirmed that this agent, although different from other recognized rickettsial species, is genotypically indistinguishable from bacteria previously detected within cat fleas and provisionally named ELB. Comparison of the phenotypic characteristics previously described for R. felis and those observed for the isolate in this study indicated some differences, although concurrent analysis of the two was not possible as no extant isolates of the first isolate of R. felis exist.
Abstract: FR160, a catechol iron chelator, and tetracyclines or norfloxacin exert in vitro additive or synergistic activity against a chloroquine-resistant Plasmodium falciparum clone. FR160 shows antagonistic effects in association with macrolides, ofloxacin, and rifampin.
Abstract: To determine the presence of Bartonella henselae bacteremia in six cats, we compared isolation using blood culture with direct immunofluorescence on blood smears. Three cats that were positive by blood culture were also positive by direct immunofluorescence, and laser confocal microscopy confirmed the intraerythrocytic location of B. henselae.
Abstract: The in vitro activity of moxifloxacin against Coxiella burnetii was compared to those of pefloxacin, ofloxacin, and doxycycline. MICs of moxifloxacin ranged from 0.5 to 1 microg/ml for the Nine Mile, Priscilla, and Q212 strains. Moxifloxacin was not bactericidal against C. burnetii at 4 microg/ml.
Abstract: In vitro activities of telithromycin compared to those of erythromycin against Rickettsia spp., Bartonella spp., Coxiella burnetii, and Ehrlichia chaffeensis were determined. Telithromycin was more active than erythromycin against Rickettsia, Bartonella, and Coxiella burnetii, with MICs of 0.5 microg/ml, 0.003 to 0.015 microg/ml, and 1 microg/ml, respectively, but was inactive against Ehrlichia chaffeensis.
Abstract: The species Bartonella and Brucella are phylogenetically closely related bacteria, both of which can produce chronic infections in humans that are difficult to cure with antibiotics. MICs of antibiotics for both species correlate poorly with the in vivo efficacy of the antibiotics. In this study we have determined MBCs of several antibiotics for this group of pathogens. Only the aminoglycosides were bactericidal, and this correlates well with the usefulness of these antibiotics for the therapy of human brucellosis and chronic Bartonella spp. infections such as endocarditis. Our data indicate that current clinical experience in treating brucellosis may help to define better the optimum antibiotic therapy for Bartonella-related diseases.
Abstract: The MICs of 13 antibiotics (doxycycline, thiamphenicol, rifampin, amoxicillin, gentamicin, co-trimoxazole, ciprofloxacin, pefloxacin, ofloxacin, erythromycin, josamycin, clarithromycin, and pristinamycin) were determined for 27 available rickettsial species or strains. We used two in vitro cell culture methods described previously: the plaque assay and the microplaque colorimetric assay. Our results confirm the susceptibilities of rickettsiae to doxycycline, thiamphenicol, and fluoroquinolones. Beta-lactams, aminoglycosides, and cotrimoxazole were not active. Typhus group rickettsiae were susceptible to all macrolides tested, whereas the spotted fever group rickettsiae, R. bellii, and R. canada were more resistant, with josamycin, a safe alternative for the treatment of Mediterranean spotted fever, being the most effective compound. Strain Bar 29, R. massiliae, R. montana, R. aeschlimannii, and R. rhipicephali, which are members of the same phylogenetic subgroup, were more resistant to rifampin than the other rickettsiae tested. Heterogeneity in susceptibility to rifampin, which we report for the first time, may explain in vivo discrepancies in the effectiveness of this antibiotic for the treatment of rickettsial diseases. We hypothesize that rifampin resistance and erythromycin susceptibility may reflect a divergence during the evolution of rickettsiae.
