Dr Norazah Ahmad MD, MSc, PhD Consultant Medical Microbiologist Head of Bacteriology Unit Institute for Medical Research Jalan Pahang, Kuala Lumpur 50588 Malaysia
Abstract: Abstract. Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is a pathogen recognized to be distinct in both phenotype and genotype from hospital-acquired MRSA. We have identified CA-MRSA cases in Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia, including their antibiotic susceptibility patterns and genotypic characteristics. Cases were identified during January to December 2009 from routine clinical specimens, where culture and antibiotic susceptibility results yielded pauci-resistant MRSA isolates suspected as being CA-MRSA. The patients' clinical data were collected and their specimens were sent for molecular confirmation and analysis. Five cases of CA-MRSA were identified, which had a multi-sensitive pattern on antibiotic susceptibility tests and were resistant to only penicillin and oxacillin. All cases were skin and soft-tissue infections, including diabetic foot with gangrene, infected scalp hematoma, philtrum abscess in a healthcare worker, thrombophlebitis complicated with abscess and infected bedsore. All five cases were confirmed MRSA by detection of mecA. SCCmec typing (ccr and mec complex) revealed SCCmec type IV for all cases except the infected bedsore case. Panton-Valentine leukocidin gene was positive in all isolates. As clinical features among methicillin-sensitive Staphylococcus aureus, CA-MRSA and "nosocomial CA-MRSA" are indistinct, early recognition is necessary in order to initiate appropriate antibiotics and infection control measures. Continual surveillance of pauci-resistant MRSA and molecular analysis are necessary in order to identify emerging strains as well as their epidemiology and transmission, both in the community and in healthcare setting.
Abstract: To characterise the cag pathogenicity island in Helicobacter pylori (H. pylori) isolates by analysing the strains' vacA alleles and metronidazole susceptibilities in light of patient ethnicity and clinical outcome.
Abstract: Co-infection of melioidosis and leptospirosis is uncommon. We report here four such cases, confirmed by blood culture for melioidosis and blood polymerase-chain reaction for leptospirosis, which occurred among rescuers involved in a search and rescue operation for a young man who was suspected to have drowned in Lubuk Yu, a recreational forest in Pahang, Malaysia. Despite treatment, three of the patients died from the co-infection.
Abstract: This study was conducted to detect the presence of heterogenous vancomycin-intermediate Staphylococcus aureus (heteroVISA) among MRSA isolates in a major hospital. Forty-three MRSA isolates with vancomycin MIC 2 microg/ml collected in 2009 was screened for heteroVISA using Etest Glycopeptide Resistance Detection (GRD) and confirmed by population analysis profile-area under curve method. The genetic relatedness of heteroVISA strains with other MRSA was examined by pulsed-field gel electrophoresis (PFGE) method. Two isolates were shown to be heteroVISA and derived from the same clone. This showed that heteroVISA strains were already present among our local strains since 2009 and were genetically related to other susceptible strains.
Abstract: We analyzed the epidemiological data of all people who were involved in the search and rescue operation in Lubuk Yu, a natural recreational forest with waterfall and stream. The hospital admission records of the cases who fulfilled the case definition and the environmental samples result taken at Lubuk Yu recreational area were studied. 153 people were exposed to this outbreak, 85 (55.5%) were professional rescuers from various government agencies and 68 (44.5%) were villagers. 21 fulfilled the case definition. Ten cases were confirmed melioidosis, six melioidosis alone and four coinfected with leptospirosis. There were eight deaths in this outbreak, seven were villagers and one professional rescuer. Overall case fatality was 70%. All confirmed melioidosis cases and seven who died had diabetes mellitus. The morbidity rate were higher among the villagers, 23.5% compared to professional rescuers, 5.9%. The case fatality rate were also higher in this group which was 100% compared to 33.3% in professional rescuers. The soil and water samples in Lubuk Yu recreational area were positive for leptospira and Burkholderia pseudomallei. The presence of co-infection and co-morbidities especially diabetes mellitus among the exposed led to the high mortality in this outbreak hence a high index of suspicion is important among the healthcare professionals in the management of melioidosis cases. To avoid similar incident in future, search and rescue operation should be only conducted by professional rescuers with appropriate personal protective equipment. A register of rescuers should be maintained for surveillance and follow up if necessary.
Abstract: Shigellosis is a major public health concern worldwide, especially in developing countries. It is an acute intestinal infection caused by bacteria of the genus Shigella, with a minimum infective dose as low as 10-100 bacterial cells. Increasing prevalence of Shigella sonnei as the etiologic agent of shigellosis in Malaysia has been reported. As there is limited information on the genetic background of S. sonnei in Malaysia, this study aimed to characterize Malaysian S. sonnei and to evaluate the prospect of using multilocus variable-number tandem-repeat (VNTR) analysis (MLVA) for subtyping of local S. sonnei.
Abstract: Serotyping is not sufficient to differentiate between Salmonella species that cause paratyphoid fever from the strains that cause milder gastroenteritis as these organisms share the same serotype Salmonella Paratyphi B (S. Paratyphi B). Strains causing paratyphoid fever do not ferment d-tartrate and this key feature was used in this study to determine the prevalence of these strains among the collection of S. Paratyphi B strains isolated from patients in Malaysia. A total of 105 isolates of S. Paratyphi B were discriminated into d-tartrate positive (dT+) and d-tartrate negative (dT) variants by two lead acetate test protocols and multiplex PCR. The lead acetate test protocol 1 differed from protocol 2 by a lower inoculum size and different incubation conditions while the multiplex PCR utilized 2 sets of primers targeting the ATG start codon of the gene STM3356. Lead acetate protocol 1 discriminated 97.1% of the isolates as S. Paratyphi B dT+ and 2.9% as dT while test protocol 2 discriminated all the isolates as S. Paratyphi B dT+. The multiplex PCR test identified all 105 isolates as S. Paratyphi B dT+ strains. The concordance of the lead acetate test relative to that of multiplex PCR was 97.7% and 100% for protocol 1 and 2 respectively. This study showed that S. Paratyphi B dT+ is a common causative agent of gastroenteritis in Malaysia while paratyphoid fever appears to be relatively uncommon. Multiplex PCR was shown to be a simpler, more rapid and reliable method to discriminate S. Paratyphi B than the phenotypic lead acetate test.
Abstract: The prevalence of antibiotic resistance varies in geographic areas. The information on the antibiotic susceptibility patterns of Helicobacter pylori (H. pylori) in our local setting is therefore relevant as a guide for the treatment options.
Abstract: From January 2008 to December 2009, 433 Streptococcus pneumoniae strains were examined to determine the serotype distribution and susceptibility to selected antibiotics. About 50% of them were invasive isolates. The strains were isolated from patients of all age groups and 33.55% were isolated from children below 5 years. The majority was isolated from blood (48.53%) and other sterile specimens (6.30%). Community acquired pneumonia (41.70%) is the most common diagnosis followed by sepsis (9.54%). Serotyping was done using Pneumotest Plus-Kit and antibiotic susceptibility pattern was determined by modified Kirby-Bauer disk diffusion method and measurement of minimum inhibitory concentration (MIC) using E-test strip. Ten most common serotypes were 19F (15.02%), 6B (10.62%), 19A (6.93%), 14 (6.70%), 1 (5.08%), 6A (5.08%), 23F (4.85%), 18C (3.93%), 3 (2.08%) and 5 (1.85%). Penicillin MIC ranged between ≤ 0.012-4 μg/ml with MIC₉₀ of 1 μg/ml. Penicillin resistant rate is 31.78%. The majority of penicillin less-susceptible strains belonged to serotype 19F followed by 19A and 6B. Based on the serotypes distribution 22 (44.00%), 28 (56.00%) and 39 (78.00%) of the invasive isolates from children ≤ 2 years were belonged to serotypes included in the PCV7, PCV10 and PCV13, respectively.
Abstract: We have analysed DNA fingerprinting patterns by pulsed-field gel electrophoresis (PFGE) of 52 unrelated Burkholderia pseudomallei strains isolated from septicemic and localized infections from Malaysian subjects. A total of 38 PFGE types were observed among 36 septicemic and 16 localized strains with no predominant pattern. Type 25 was seen in 2 epidemiologically related strains, suggesting human to human transmission. Twelve PFGE types were shared among 26 strains (21 septicemic and 5 localized) showing close genetic relatedness with coefficient of similarity of 0.81 to 1.0. The other 26 strains (15 septicemic and 11 localized) were unrelated as shown by the similarity coefficient of < 0.8. This study showed that our B. pseudomallei strains in Malaysia were mainly heterogenous with no predominant type both in septicemic or localized strains.
Abstract: Brucellosis is a zoonotic disease which can be transmitted by direct or indirect contact with infected animal or their products. It is an important public health problem but little is known on brucellosis in the Malaysian population. The aim of this study was to determine the presence of Brucella antibodies using commercial Brucella IgG and IgM ELISA kits (Vircell, SL, Barcelona Spain). A total of 184 sera from suspected patients were received from 16 hospitals in Malaysia over the years 2004 to 2009. Only 10 serum samples (5.4%) were positive for Brucella antibodies in which 5 showed the presence of both IgM and IgG. Most of the positive patients were occupationally involved with animals. This study suggests the seroprevalance of brucellosis among individuals who have contact with infected animals in Malaysia is low.
Abstract: Treatment failures have been reported in MRSA infections with vancomycin MIC of 2 microgram/mL. The prevalence of Staphylococcus aureus clinical strains with high MICs is not known in Malaysian hospitals. This study was conducted to determine the MICs of Staphylococcus aureus isolates obtained from clinical samples from 6 major Malaysian hospitals. A total of 300 MSSA and 300 MRSA strains from invasive infections and non-colonizers were included in this study. Vancomycin MICs were determined by broth microdilution (BMD) and E-test method. By BMD method, the majority of MSSA strains (87%) showed vancomycin MIC of 0.5 microgram/mL while MIC of 1.0 microgram/mL was observed more frequently in MRSA compared to MSSA (41% and 13%, respectively). By E-test method, higher MIC values of 1.5 microgram/mL and 2.0microg/mL were observed in 50% and 16% of MSSA and 51% and 30% of MRSA respectively. MRSA strains were also shown to have a significantly higher vancomycin MICs than the MSSA strains (p<0.05). Analysis of bacteraemia isolates showed a higher proportion of MRSA with E-test vancomycin MIC of 2microg/mL compared to MSSA (39% vs. 13%) (p<0.05). Even though the MIC values were dependent on the method used, the high vancomycin MICs of >/= 1 microg/ml observed among our strains is a cause of concern as it may have an impact on the success of vancomycin treatment.
Abstract: AIM: To characterize the types of mutations present in the 23S rRNA genes of Malaysian isolates of clarithromycin-resistant Helicobacter pylori (H pylori). METHODS: Clarithromycin susceptibility of H pylori isolates was determined by E test. Analyses for point mutations in the domain V of 23S rRNA genes in clarithromycin-resistant and -sensitive strains were performed by sequence analysis of amplified polymerase chain reaction products. Restriction fragment length polymorphism was performed using BsaI and MboII enzymes to detect restriction sites that correspond to the mutations in the clarithromycin-resistant strains. RESULTS: Of 187 isolates from 120 patients, four were resistant to clarithromycin, while 183 were sensitive. The MIC of the resistant strains ranged from 1.5 to 24 microg/mL. Two isolates had an A2142G mutation and another two had A2143G mutations. A T2182C mutation was detected in two out of four clarithromycin-resistant isolates and in 13 of 14 clarithromycin-sensitive isolates. Restriction enzyme analyses with BsaI and MboII were able to detect the mutations. CONCLUSION: Clarithromycin resistance is an uncommon occurrence among Malaysian isolates of H pylori strains and the mutations A2142G and A2143G detected were associated with low-level resistance.
Abstract: A pair of primers targeting the hlyA gene for Vibrio cholerae which could distinguish the classical from El Tor biotypes was designed and combined with other specific primers for ompW, rfb complex, and virulence genes such as ctxA, toxR, and tcpI in a multiplex PCR (m-PCR) assay. This m-PCR correctly identified 39 V. cholerae from clinical, water and seafood samples. The efficiency of this multiplex PCR (m-PCR) was compared with conventional biochemical and serogrouping methods. One O139 and 25 O1 V. cholerae strains including 10 environmental strains harbored all virulence-associated genes except 1 clinical strain which only had toxR and hlyA genes. Thirteen environmental strains were classified as non-O1/non-O139 and had the toxR and hlyA genes only. The detection limit of m-PCR was 7 x 10(4) cfu/ml. The m-PCR test was reliable and rapid and reduced the identification time to 4 h.
Abstract: This study was conducted to determine whether there was any genetic heterogeneity among Helicobacter pylori strains isolated from the antrum and corpus of the same individual in a Malaysian population and to determine the presence of heterogeneous susceptibility of the isolates by comparing PCR-RAPD and antibiotic profiles. Forty-four H. pylori isolates cultured from the antrum and corpus of 22 patients were analyzed. Antibiotic susceptibility testing was carried out by minimum inhibitory concentration determination, using E-Test method strips. PCR-RAPD was carried out on all the strains and the profiles generated were analysed for cluster analysis. Twenty-nine different PCR-RAPD profiles were observed in the 44 isolates. Fifteen pairs of the isolates from the same patients had the same PCR-RAPD patterns while in 7 pairs, the profiles were different. The strains were clustered into 2 separate clusters at a low coefficient of similarity, where most of the strains were in cluster 1. The degree of similarity was very low among most of the isolates. Most of the patients (16 of 22) were infected with strains that have the same antibiotic susceptibility profiles. Out of these, only 10 pairs shared the same PCR-RAPD and antibiotic profiles. Five pairs of isolates with similar PCR-RAPD profiles differed in their antibiotic profiles due to metronidazole resistance in one of the sites. A large degree of genetic heterogeneity was observed among H. pylori strains circulating among Malaysian patients. An individual patient can be infected with multiple strains and the strains can be antibiotic resistant.
Abstract: Community-acquired meticillin-resistant Staphylococcus aureus (CA-MRSA) occurring among hospital isolates in Malaysia has not been reported previously. As CA-MRSA reported worldwide has been shown to carry SCCmec types IV and V, the aim of this study was to determine the SCCmec types of MRSA strains collected in Malaysia from November 2006 to June 2008. From a total of 628 MRSA isolates, 20 were SCCmec type IV, whilst the rest were type III. Further characterization of SCCmec type IV strains revealed 11 sequence types (STs), including ST22, with the majority being ST30/Panton-Valentine leukocidin positive. Eight out of nine CA-MRSA were ST30, one was ST80, and all were sensitive to co-trimoxazole and gentamicin. Five new STs designated ST1284, ST1285, ST1286, ST1287 and ST1288 were discovered, suggesting the emergence of novel clones of MRSA circulating in Malaysian hospitals. The discovery of the ST22 strain is a cause for concern because of its ability to replace existing predominant clones in certain geographical regions.
Abstract: A 64-year old patient, who had bacteraemia, did not respond to vancomycin despite the MRSA isolate being sensitive to the antibiotic at MIC 2 microg/mL. Electron microscopy of the MRSA isolate showed thickening of the cell wall, which was not observed in MRSA with lower vancomycin MIC.
Abstract: Subdural collections caused by Salmonella infection are rarely encountered in children. We present two cases caused by non-typhi Salmonella, one a four-and-a-half-month-old boy presenting with subdural effusion, and the other, a 16-month-old boy with empyema. The diagnosis was confirmed on blood and subdural pus cultures. One patient had status epilepticus following focal fit, and the other had prolonged fever without any localising signs of infection on admission. They responded well to prompt surgical drainage and prolonged systemic antibiotic therapy. Contrary to previous reports, both patients showed favourable outcome in terms of neurological sequelae.
Abstract: Legionella pneumophila are intracellular pathogens, associated with human disease, attributed to the presence and absence of certain virulent genes. In this study, virulent gene loci (lvh and rtxA regions) associated with human disease were determined. Thirty-three cooling tower water isolates, isolated between 2004 to 2006, were analyzed for the presence of these genes by PCR method. Results showed that 19 of 33 (57.5%) of the L. pneumophila serogroup 1 isolates have both the genes. Six (18.2%) of the isolates have only the lvh gene and 2 (6.1%) of the isolates have only the rtxA gene. However, both genes were absent in 6 (18.2%) of the L. pneumophila isolates. The result of our study provides some insight into the presence of the disease causing L. pneumophila serogroup 1 in the environment. Molecular epidemiological studies will provide better understanding of the prevalence of the disease in Malaysia.
Abstract: The use of pathogen genome sequence data for the control and management of infections remains an ongoing challenge. We describe a broadly applicable, web-enabled approach that can be used to develop bacteria-specific polymerase chain reaction (PCR) assays. Salmonella enterica Paratyphi A has emerged as a major cause of enteric fever in Asia. Culture-based diagnosis is slow and frequently negative in patients with suspected typhoid and paratyphoid fever, potentially compromising patient management and public health. We used the MobilomeFINDER web-server to perform in silico subtractive hybridization, thus identifying 43 protein-coding sequences (CDSs) that were present in two Paratyphi A strains but not in other sequenced Salmonella genomes. After exclusion of 29 CDSs found to be variably present in Paratyphi A strains by microarray hybridization and grouping of remaining CDSs by genomic location, four dispersed targets (stkF, spa2473, spa2539, hsdM) were used to develop a highly discriminatory multiplex PCR assay. All 52 Paratyphi A strains within the diverse panel investigated produced one of two pathognomonic four-band signatures. Given rapid and ongoing expansion of DNA and comparative genomics databases, our universally accessible web-server-supported do-it-yourself approach offers the potential to contribute significantly to the rapid development of species-, serovar-, or pathotype-specific PCR assays targeting pre-existing and emerging bacterial pathogens.
Abstract: Invasive Neisseria meningitidis infection is rare but carries a high mortality rate. The carriage rate in the normal population is around 10% and can be higher in confined populations. A study on the prevalence of carriage of N. meningitidis was conducted among 3195 army recruits after 2 months of intensive training in an army camp. N. meningitidis was isolated from 37.0% of these recruits. Two hundred and ten of N. meningitidis isolates were subjected to serogrouping and 100 to antibiotic sensitivity testing by the disc diffusion method and E-test for penicillin. Ten (4.8%) of 210 Neisseria meningitidis serogrouped belonged to serogroup W135, 3.33% serogroup A and 81.4% belonged to either serogroup X, Y or Z. With the agar disc diffusion method, all the N. meningitidis showed susceptiblity to chloramphenicol, rifampicin, cefotaxime and levofloxacin; 85% of the strains were resistant to cotrimoxazole and 12.5% resistant to penicillin. However, based on minimum inhibitory concentration, none of the Neisseria meningitidis tested was resistant to penicillin.
Abstract: The in-vitro susceptibility of quinupristin/dalfopristin, levofloxacin and moxifloxacin against methicillin-resistant Staphylococcus aureus (MRSA) strains, which are also resistant to fusidic acid and rifampicin were carried out to determine whether these antibiotics can be used as an alternative treatment for multiply resistant MRSA strains. The minimum inhibitory concentrations (MIC) of these antibiotics were determined by E-test. Quinupristin/dalfopristin had good activity (MIC90 = 1 mg/L) against these strains while most of the strains showed intermediate resistance to moxifloxacin with MIC90 = 2 mg/L). However, more than 90% of these strains were resistant to levofloxacin with the MICs that ranged from 8 mg/L to 16 mg/L with the majority inhibited at 8 mg/L.
Abstract: Medicinal plants have many traditional claims including the treatment of ailments of infectious origin. In the evaluation of traditional claims, scientific research is important. The objective of the study was to determine the presence of antibacterial activity in the crude extracts of some of the commonly used medicinal plants in Malaysia, Andrographis paniculata, Vitex negundo, Morinda citrifolia, Piper sarmentosum, and Centella asiatica. In this preliminary investigation, the leaves were used and the crude extracts were subjected to screening against five strains of bacteria species, Methicillin Resistant Staphylococcus aureus (MRSA), Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa and Escherichia coli, using standard protocol of Disc Diffusion Method (DDM). The antibacterial activities were assessed by the presence or absence of inhibition zones and MIC values. M. citrifolia, P. sarmentosum and C. asiatica methanol extract and A. paniculata (water extract) have potential antibacterial activities to both gram positive S. aureus and Methicillin Resistant S. aureus (MRSA). None of the five plant extracts tested showed antibacterial activities to gram negative E. coli and K. pneumoniae, except for A. paniculata and P. sarmentosum which showed activity towards P. aeruginosa. A. paniculata being the most potent at MIC of 2 g/disc. This finding forms a basis for further studies on screening of local medicinal plant extracts for antibacteria properties.
Abstract: Acanthamoeba is an uncommon cause of keratitis but one of the most severe because of the prolonged and painful course of the disease and poor visual outcome. Although contact lens use is the principal risk factor, about 10% of cases occur following trauma and exposure to contaminated soil or water. Two cases of Acanthamoeba keratitis involving women contact lens wearers have previously been reported in Malaysia but this is the first time, a non contact lens related Acanthamoeba keratitis is reported. The case involved a 28 year old Indonesian male construction worker who had a trauma of the right eye during work. His eye was struck by sand and dust particles after which he quickly washed with water from an open tank at the construction site. He experienced pain, redness, glaring and blurring of vision of the right eye three days later. The diagnosis was missed at initial presentation but culture of the corneal scraping had proven Acanthamoeba as the aetiological agent. The history and clinical findings of this trauma related Acanthamoeba keratitis are briefly discussed.
Abstract: This study was conducted to determine the molecular epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) in Malaysian hospitals. A total of 264 MRSA isolates from eight hospitals were subjected to typing by pulsed-field gel electrophoresis (PFGE) of SmaI restricted DNA. Antibiotic disk susceptibility testing was also carried out to determine their resistance patterns. Thirty-one PFGE pattern types were identified. Three major pattern types A, ZC and K were found with type A the predominant profile in c. 80% of strains and present in all hospitals. Unlike type A, other DNA pattern types were unique to the hospitals in which they were isolated. PFGE type A also consisted of strains that were multiply antibiotic resistant. The presence of a single predominant PFGE type in Malaysian hospitals is an important finding which suggests that inter-hospital spread of MRSA had occurred frequently and regularly.
Abstract: The carriage and antibiotic susceptibility patterns of Staphylococcus aureus in the community were determined. Nasal, throat and axillary swabs were taken from 100 healthy adults and 90 disabled nursing home inmates. Antibiotic disc susceptibility testing was conducted following the NCCLS method. Staphylococcus aureus carriage was noted in 29% of healthy adults and 47.7% of nursing home inmates. Out of 79 strains, resistance to antibiotics were as follows; penicillin (92.4%), genetamicin (2.5%), tetracycline (6.3%), fusidic acid (11.3%), erythromycin (3.8%), pefloxacin (5.1%), mupirocin (3.8%), amikacin (3.8%), ciprofloxacin (2.5%) and chloramphenicol (2.5%). Methicillin-resistant Staphylococcus aureus was not isolated. Multiple colonizations and multi-antibiotic resistant Staphylococcus aureus were shown to occur in healthy individuals without risk factors and not previously hospitalized.
Abstract: The emergence and spread of multiresistant methicillin-resistant Staphylococcus aureus (MRSA) strains, especially those resistant to fusidic acid and rifampicin, in Malaysian hospitals is of concern. In this study DNA fingerprinting by PFGE was performed on fusidic acid- and rifampicin-resistant isolates from Malaysian hospitals to determine the genetic relatedness of these isolates and their relationship with the endemic MRSA strains. In all, 32 of 640 MRSA isolates from 9 Malaysian hospitals were resistant to fusidic acid and rifampicin. Seven PFGE types (A, ZC, ZI, ZJ, ZK, ZL and ZM) were observed. The commonest type was type ZC, seen in 72% of isolates followed by type A, seen in 13%. Each of the other types (ZI, ZJ, ZK, ZL and ZM) was observed in a single isolate. Each type, even the commonest, was found in only one hospital. This suggests that the resistant strains had arisen from individual MRSA strains in each hospital and not as a result of the transmission of a common clone.
Abstract: Methicillin-resistant Staphylococcus aureus (MRSA) has been prevalent in our hospital over the last three years. Differentiation among MRSA strains by DNA typing in addition to antibiotic resistance pattern surveillance is crucial in order to implement infection control measures. The aim of this study was to characterize MRSA isolates from patients admitted to Hospital Universiti Kebangsaan Malaysia (HUKM) by phenotypic (analyses of antibiotic susceptibility pattern) and genotypic (PFGE) techniques to determine the genetic relatedness of the MRSA involved and to identify endemic clonal profiles of MRSA circulating in HUKM. Seventy one MRSA strains collected between January to March 2000 from patients from various wards in HUKM were tested for antimicrobial resistance and typed by pulsed-field gel electrophoresis (PFGE). Four major types of PFGE patterns were identified (A, B, C and D) among MRSA strains. Two predominant PFGE types were recognised, Type A (59.2%) and Type B (33.8%). Most of these strains were isolated from ICU, Surgical wards and Medical wards. MRSA strains with different PFGE patterns appeared to be widespread among wards. Strains with the same antibiotype could be of different PFGE types. Most of isolates were resistant to ciprofloxacin, erythromycin, gentamicin and penicillin. One isolate with a unique PFGE pattern Type D and susceptible to gentamicin was identified as a different clone. Some isolates obtained from the same patient showed different PFGE subtypes suggesting that these patients were infected/colonized with multiple MRSA strains. PFGE analysis suggests that MRSA strains with different PFGE types was propagated within our hospital. The relationship between antibiotic susceptibility and PFGE patterns was independent. The ability of PFGE technique in differentiating our MRSA strains make it a method of choice for investigating the source, transmission and spread of nosocomial MRSA infection, and thus an appropriate control programme can be implemented to prevent the spread of MRSA infection.
Abstract: AIM OF STUDY: To determine and compare the pulsed-field gel electrophoresis (PFGE) patterns of endemic MRSA strains in 2 major Malaysian hospitals and to compare the PFGE patterns with antibiotypes of the strains studied. METHODS: Fifty-six MRSA strains selected randomly between September 1997 and July 1998 from Hospital Queen Elizabeth (HQE) and Hospital Umum Sarawak (HUS) were tested for antimicrobial resistance and DNA fingerprinting was carried out by pulsed-field gel electrophoresis (PFGE) technique. RESULTS: Seven PFGE types were recognised (A, B, C, D, E and F). All 7 PFGE types were observed in HQE while only 2 PFGE types (B, C) were noted in HUS strains. There is a predominance of a single PFGE pattern (type B) in both hospitals, as seen in 46% of HQE strains and 89% of HUS strains. Subtype B2 was the commonest subtype in HQE while subtype B1 predominated in HUS. Strains resistant to fusidic acid and rifampicin exhibited PFGE type F that is unique to HQE. All strains were resistant to penicillin, erythromycin, cotrimoxazole, tetracycline and gentamicin. Strains with the same antibiotic susceptibility pattern can be different PFGE types. CONCLUSION: Molecular typing of the MRSA by PFGE is a useful tool in the study of endemic strains present in an institution. Strains in HQE were found to be more heterogeneous than HUS strains. Common PFGE types can also be seen in both hospitals suggesting that some of the strains was genetically related and has propagated within and between the 2 hospitals. Our findings also indicate that the relationship between antibiotic susceptibility and PFGE patterns was not close and antibiograms should not be relied upon for typing strains in epidemiological studies. By knowing the DNA fingerprints of the isolates endemic in each hospital, the spread of MRSA with a particular PFGE type can be monitored within and between hospitals.
Abstract: Four hundred methicillin-resistant Staphylococcus aureus strains (MRSA) from different geographical areas in Malaysia were tested for mupirocin susceptibility using minimum inhibitory concentration (MIC) determination. The majority of these strains (98.75%) were susceptible to mupirocin with MICs of < or = 4 mg/l. Fifty-percent of these strains had MICs of 0.125 mg/l or less while 90% of the strains had MICs of 1 mg/l or less. Mupirocin resistance was detected in five strains (1.25%) and one of these (0.25%) had an MIC of 64 mg/l and the other four strains (1%), high-level resistance with MICs > 512 mg/l. Even though the rate of mupirocin resistance in MRSA is still low in Malaysia, its presence calls for a strict policy on mupirocin usage in Malaysian hospitals.
Abstract: The detection of Vibrio cholerae 01 from the aquatic environment of Daro and Bintulu in Sarawak was carried out following an outbreak of cholera. Conventional culture methods and detection of ctx gene by polymerase chain reaction technique were carried out on 80 water samples. Only one sample was positive by culture methods while 8 were positive by PCR. DNA finger printing by pulsed-field gel electrophoresis showed that the clinical isolates in Daro and Bintulu were genetically identical while the environmental isolate was closely related. Recovery of Vibrio cholerae by culture method is poor and newer methods of detection should be developed.
Abstract: Three monoclonal antibodies (McAb) were produced against soluble antigens of Legionella pneumophila serogroup 1 which was cultured on BCYE agar. The McAbs were all of the IgM isotype. The McAbs were used in the McAb-based ELISA for detection of circulating L. pneumophila antigens in 186 sera collected from patients with symptoms and signs suggestive of atypical pneumonia. The normal reference optical (OD) density value of each of the McAbs was determined using 44 sera collected from healthy blood donors. The antigen positivity rates for the McAbs 1C7.2B, 2B2.10F and 2B2.11E were 11.3%, 7.7% and 22.2% respectively. Antigen positivity of the McAb 2B2.10F was significantly higher in the younger age group (p < 0.05). There is no significant association between the antigen positivity with age and sex for all the McAbs. There was no cross-reaction demonstrated between the McAbs with other bacterial antigens.
Abstract: A total of 402 Escherichia coli isolates were obtained from a variety of food samples and screened for enteropathogenic E. coli (EPEC). Screening was carried out using 15 specific monovalent antisera from Murex Diagnostic Limited. A total of 19 E. coli isolates were serotyped as EPEC. The EPEC strains were shown to belong to 8 serotypes. Eight out of 19 EPEC strains belonged to serotype 018C:K77 (B21). Seventeen out of 19 of the EPEC strains were isolated from cooked food. The presence of E. coli in cooked food is an indicator of fecal contamination and a sign of unhygienic food handling. The presence of EPEC in food could be a potential source of food-borne outbreak. Hygiene training for every food-handler is a necessity.
Abstract: Interpretation of the indirect hemagglutination test (IHA) for melioidosis in endemic areas is difficult because of the presence of antibodies in apparently healthy individuals. Fifty-three out of 200 healthy blood donors in Malaysia showed positive antibody titers (> or = 1 : 40) against Burkholderia pseudomallei. Seven percent had an IHA titer of 1 : 40, 11% had an IHA titer of 1 : 80 while 8.5% had a titer > or = 1 : 160. Out of 258 sera sent for melioidosis serology, 7% of the patients had an IHA titer of 1 : 40, 9% had an IHA titer of 1 : 80 while 20% had an IHA titer of > or = 1 : 160. If a titer of > or = 1 : 80 is taken as cut off point for positivity, 29% of the patients had positive melioidosis serology. Increasing the positivity threshold may jeopardize the sensitivity of the test. A more specific and sensitive test is needed.
Abstract: A 34-year-old laboratory worker developed murine typhus after an accidental splashing of Rickettsia typhi over her right eye and lips. Indirect immunoperoxidase test showed a four-fold increase in titre to Rickettsia typhi. She responded well to doxycycline.
