Claire Janoir's Publications List

Emerging monoclonal antibodies against Clostridium difficile infection.

2018-04-06T10:04:39Z

Clostridium difficile infections are characterized by a high recurrence rate despite antibiotic treatments and there is an urgent need to develop new treatments such as fecal transplantation and immonotherapy. Besides active immunotherapy with vaccines, passive immunotherapy has shown promise, especially with monoclonal antibodies. Areas covered: Herein, the authors review the different assays per...

Séverine Péchiné, Claire Janoir, Anne Collignon (2017) Expert opinion on biological therapy 17: 4 415-427

Clostridium difficile flagellin FliC: Evaluation as adjuvant and use in a mucosal vaccine against Clostridium difficile.

2018-04-06T10:04:39Z

The immunogenicity of bacterial flagellin has been reported in different studies. By its close interaction with the immune system, the flagellin represents an interesting adjuvant and vaccine candidate. Salmonella Typhimurium flagellin has already been tested as adjuvant to stimulate mucosal immunity. Here, we assessed the ability of Clostridium difficile flagellin FliC to act as a mucosal adjuvan...

Jean-François Bruxelle, Assaf Mizrahi, Sandra Hoÿs, Anne Collignon, Claire Janoir, Séverine Péchiné (2017) PloS one 12: 11

Clostridium difficile flagella induce a pro-inflammatory response in intestinal epithelium of mice in cooperation with toxins.

2018-04-06T10:19:09Z

Clostridium difficile is the most important enteropathogen involved in gut nosocomial post-antibiotic infections. The emergence of hypervirulent strains has contributed to increased mortality and morbidity of CDI. The C. difficile toxins contribute directly to CDI-associated lesions of the gut, but other bacterial factors are needed for the bacteria to adhere and colonize the intestinal epithelium...

Jameel Batah, Hussein Kobeissy, Phuong Trang Bui Pham, Cécile Denève-Larrazet, Sarah Kuehne, Anne Collignon, Claire Janoir-Jouveshomme, Jean-Christophe Marvaud, Imad Kansau (2017) Scientific reports 7: 1

The alternative sigma factor σplays a crucial role in adaptive strategies of Clostridium difficile during gut infection.

2018-04-06T10:05:06Z

Clostridium difficile is a major cause of diarrhoea associated with antibiotherapy. Exposed to stresses in the gut, C. difficile can survive by inducing protection, detoxification and repair systems. In several firmicutes, most of these systems are controlled by the general stress response involving σ. In this work, we studied the role of σin the physiopathology of C. difficile. We showed that t...

Nicolas Kint, Claire Janoir, Marc Monot, Sandra Hoys, Olga Soutourina, Bruno Dupuy, Isabelle Martin-Verstraete (2017) Environmental microbiology 19: 5 1933-1958

Biofilm Structures in a Mono-Associated Mouse Model ofInfection.

2018-04-06T10:04:39Z

infection (CDI) is a major healthcare-associated disease with high recurrence rates. Host colonization is critical for the infectious process, both in first episodes and in recurrent disease, with biofilm formation playing a key role. The ability ofto form a biofilm on abiotic surfaces is established, but has not yet been confirmed in the intestinal tract. Here, four different isolates of, which a...

Anna P Soavelomandroso, Françoise Gaudin, Sandra Hoys, Valérie Nicolas, Gayatri Vedantam, Claire Janoir, Sylvie Bouttier (2017) Frontiers in microbiology 8:

Immunogenic properties of the surface layer precursor of Clostridium difficile and vaccination assays in animal models.

2018-04-06T10:04:39Z

Clostridium difficile is an opportunistic pathogen causing gut inflammation generally associated with an intestinal dysbiosis due to antibiotics. Several virulence factors have been identified as playing a key role in gut colonization. The surface-layer proteins, comprised of two proteins, the high molecular weight SlpA (HMW-SLP) and the low molecular weight SlpA (LMW-SLP), are the most abundant p...

J-F Bruxelle, A Mizrahi, S Hoys, A Collignon, C Janoir, S Péchiné (2016) Anaerobe 37: 78-84

Deciphering Adaptation Strategies of the Epidemic Clostridium difficile 027 Strain during Infection through In Vivo Transcriptional Analysis.

2018-04-06T10:04:39Z

Clostridium difficile is responsible for a wide spectrum of infection from asymptomatic carriage to severe, relapsing colitis. Since 2003, C. difficile infections have increased with a higher morbidity and mortality due to the emergence of epidemic and hypervirulent C. difficile strains such as those of the epidemic lineage 027/BI/NAP1. To decipher the hypervirulence and epidemicity of 027 strains...

Imad Kansau, Amira Barketi-Klai, Marc Monot, Sandra Hoys, Bruno Dupuy, Claire Janoir, Anne Collignon (2016) PloS one 11: 6

Virulence factors of Clostridium difficile and their role during infection.

2018-04-06T10:04:39Z

Clostridium difficile is the prominent etiological agent of healthcare-associated diarrhea. The disease symptoms range from mild diarrhea to life-threatening pseudomembranous colitis. The main risk factor for developing an infection after contamination by the resistant spores is the disruption of the gut microbiota, allowing the spores to germinate. The colonization of the gut is likely to be gove...

Claire Janoir (2016) Anaerobe 37: 13-24

Insight Into Resistance Phenotypes of Emergent Non 13-valent Pneumococcal Conjugate Vaccine Type Pneumococci Isolated From Invasive Disease After 13-valent Pneumococcal Conjugate Vaccine Implementation in France.

2018-04-06T10:04:39Z

Background. In 2010, the pneumococcal 13-valent conjugate vaccine (PCV13), containing 6 additional serotypes including the multidrug-resistant 19A, replaced the PCV7 in France. This study aimed at analyzing trends in antibiotic resistance in invasive pneumococcal disease (IPD) isolates in France after PCV13 introduction. Methods. A total of 5243 pneumococci isolated from IPD in 2008-2009 (la...

Claire Janoir, Agnès Lepoutre, Laurent Gutmann, Emmanuelle Varon (2016) Open forum infectious diseases 3: 1

The Clostridium difficile Protease Cwp84 Modulates both Biofilm Formation and Cell-Surface Properties.

2015-10-28T10:02:53Z

Clostridium difficile is responsible for 15-20% of antibiotic-associated diarrheas, and nearly all cases of pseudomembranous colitis. Among the cell wall proteins involved in the colonization process, Cwp84 is a protease that cleaves the S-layer protein SlpA into two subunits. A cwp84 mutant was previously shown to be affected for in vitro growth but not in its virulence in a hamster model. In thi...

Véronique Pantaléon, Anna Philibertine Soavelomandroso, Sylvie Bouttier, Romain Briandet, Bryan Roxas, Michele Chu, Anne Collignon, Claire Janoir, Gayatri Vedantam, Thomas Candela (2015) PloS one 10: 4

Impact of the pneumococcal conjugate vaccines on invasive pneumococcal disease in France, 2001-2012.

2015-10-28T10:02:53Z

Vaccination with the 7-valent pneumococcal conjugate vaccine (PCV7) was recommended in France in 2003 for children <2 years. The 13-valent conjugate vaccine (PCV13) replaced PCV7 in 2010. We assessed the impact of PCVs vaccination on the incidence of invasive pneumococcal diseases (IPD) in French children (0-15 years) and adults (>15 years).

A Lepoutre, E Varon, S Georges, F Dorléans, C Janoir, L Gutmann, D Lévy-Bruhl, , (2015) Vaccine 33: 2 359-366

Biofilms of Clostridium species.

2015-10-28T10:02:53Z

The biofilm is a microbial community embedded in a synthesized matrix and is the main bacterial way of life. A biofilm adheres on surfaces or is found on interfaces. It protects bacteria from the environment, toxic molecules and may have a role in virulence. Clostridium species are spread throughout both environments and hosts, but their biofilms have not been extensively described in comparison w...

Véronique Pantaléon, Sylvie Bouttier, Anna Philibertine Soavelomandroso, Claire Janoir, Thomas Candela (2014) Anaerobe 30: 193-198

Clonal expansion of the macrolide resistant ST386 within pneumococcal serotype 6C in France.

2015-10-28T10:02:53Z

In France, the use of the 7-valent pneumococcal conjugate vaccine (PCV7) lead to an overall significant decrease in PCV7 invasive pneumococcal disease (IPD) incidence. However, the decrease in vaccine serotype prevalence was partially counterbalanced by the serotype replacement phenomenon. In this study, we analyzed the role of the newly described serotype 6C as one of the replacement serotypes. T...

Claire Janoir, Robert Cohen, Corinne Levy, Edouard Bingen, Agnès Lepoutre, Laurent Gutmann, Emmanuelle Varon, (2014) PloS one 9: 3

Influence of environmental conditions on the expression and the maturation process of the Clostridium difficile surface associated protease Cwp84.

2015-10-28T10:02:53Z

Expression of the Clostridium difficile protease gene, cwp84, was moderately up-regulated by decreasing pH due to glucose metabolism. Purification under different pH conditions influenced the proteolytic process of Cwp84. Given this, acidic pH could favor the appearance of different forms of Cwp84 that may have different roles during the infection.

Diana Chapetón Montes, Anne Collignon, Claire Janoir (2013) Anaerobe 19: 79-82

Adaptive strategies and pathogenesis of Clostridium difficile from in vivo transcriptomics.

2015-10-28T10:02:53Z

Clostridium difficile is currently the major cause of nosocomial intestinal diseases associated with antibiotic therapy in adults. In order to improve our knowledge of C. difficile-host interactions, we analyzed the genome-wide temporal expression of C. difficile 630 genes during the first 38 h of mouse colonization to identify genes whose expression is modulated in vivo, suggesting that they may ...

Claire Janoir, Cécile Denève, Sylvie Bouttier, Frédéric Barbut, Sandra Hoys, Laxmee Caleechum, Diana Chapetón-Montes, Fátima C Pereira, Adriano O Henriques, Anne Collignon, Marc Monot, Bruno Dupuy (2013) Infection and immunity 81: 10 3757-3769

Expanding the repertoire of gene tools for precise manipulation of the Clostridium difficile genome: allelic exchange using pyrE alleles.

2015-10-28T10:02:53Z

Sophisticated genetic tools to modify essential biological processes at the molecular level are pivotal in elucidating the molecular pathogenesis of Clostridium difficile, a major cause of healthcare associated disease. Here we have developed an efficient procedure for making precise alterations to the C. difficile genome by pyrE-based allelic exchange. The robustness and reliability of the method...

Yen Kuan Ng, Muhammad Ehsaan, Sheryl Philip, Mark M Collery, Clare Janoir, Anne Collignon, Stephen T Cartman, Nigel P Minton (2013) PloS one 8: 2

Immunization of hamsters against Clostridium difficile infection using the Cwp84 protease as an antigen.

2011-10-13T09:21:40Z

Clostridium difficile is a pathogen responsible for diarrhoea and colitis, particularly after antibiotic treatment. We evaluated the C. difficile protease Cwp84, found to be associated with the S-layer proteins, as a vaccine antigen to limit the C. difficile intestinal colonization and therefore the development of the infection in a clindamycin-treated hamster model. First, we evaluated the immune...

Séverine Péchiné, Cécile Denève, Alban Le Monnier, Sandra Hoys, Claire Janoir, Anne Collignon (2011) FEMS Immunol Med Microbiol 63: 1 73-81

A proposed nomenclature for cell wall proteins of Clostridium difficile.

2011-10-13T09:21:40Z

Strains of Clostridium difficile produce a number of surface-localized proteins, including the S-layer proteins (SLPs) and other proteins that have suspected roles in pathogenesis. During the Third International C. difficile Symposium (Bled, Slovenia, September 2010) discussions were held on standardization of nomenclature. Gene designations were proposed for the large family of cell wall proteins...

Robert P Fagan, Claire Janoir, Anne Collignon, Paola Mastrantonio, Ian R Poxton, Neil F Fairweather (2011) J Med Microbiol 60: Pt 8 1225-1228

Encapsulation of Cwp84 into pectin beads for oral vaccination against Clostridium difficile.

2011-10-13T09:21:40Z

We have designed an oral vaccine against Clostridium difficile infection. The virulent factor Cwp84, that is a cystein protease highly immunogenic in patients with C. difficile-associated disease, was entrapped within pectin beads. Beads encapsulating Cwp84 were shown to be stable in the simulated intestinal medium and to release the cystein protease once in the simulated colonic medium. Three gro...

Chiara Sandolo, Séverine Péchiné, Alban Le Monnier, Sandra Hoys, Claire Janoir, Tommasina Coviello, Franco Alhaique, Anne Collignon, Elias Fattal, Nicolas Tsapis (2011) Eur J Pharm Biopharm 79: 3 566-573

Localization of the Clostridium difficile Cysteine Protease Cwp84 and Insights into Its Maturation Process.

2011-10-13T09:21:40Z

Clostridium difficile is a nosocomial pathogen involved in antibiotic-associated diarrhea. C. difficile expresses a cysteine protease, Cwp84, which has been shown to degrade some proteins of the extracellular matrix and play a role in the maturation of the precursor of the S-layer proteins. We sought to analyze the localization and the maturation process of this protease. Two identifiable forms of...

Diana Chapetónmontes, Thomas Candela, Anne Collignon, Claire Janoir (2011) J Bacteriol 193: 19 5314-5321

Accuracy of MIC determination for Streptococcus pneumoniae using the Sirscan2000automatic MIC determination system.

2011-10-13T09:21:40Z

The Sirscan2000automatic MIC determination (SIR-MD) system is a new system for MIC determination based on the automatic detection of growth of bacteria spotted onto agar medium using a camera scan. To evaluate its accuracy, 3608 Streptococcus pneumoniae clinical isolates yielding 18,165 MICs were tested in parallel with the SIR-MD and a standard interpretive antibiogram procedure. The overall perc...

Patrick Grohs, Claire Janoir, Sophie Grondin, Sylvie Simon, Gaëlle Bonnet, Laura Henry, Laurent Gutmann, Emmanuelle Varon (2011) Diagn Microbiol Infect Dis 70: 3 399-403

Chemical probes of surface layer biogenesis in Clostridium difficile.

2011-10-13T09:21:40Z

Clostridium difficile, a leading cause of hospital-acquired infection, possesses a dense surface layer (S-layer) that mediates host-pathogen interactions. The key structural components of the S-layer result from proteolytic cleavage of a precursor protein, SlpA, into high- and low-molecular-weight components. Here we report the discovery and optimization of the first inhibitors of this process in ...

T H Tam Dang, Lucia de la Riva, Robert P Fagan, Elisabeth M Storck, William P Heal, Claire Janoir, Neil F Fairweather, Edward W Tate (2010) ACS Chem Biol 5: 3 279-285

New trends in Clostridium difficile virulence and pathogenesis.

2011-10-13T09:21:40Z

The disease spectrum caused by Clostridium difficile infection ranges from antibiotic-associated diarrhoea to life-threatening clinical manifestations such as pseudomembranous colitis. C. difficile infection is precipitated by antimicrobial therapy that causes a disruption of the normal colonic microbiota, predisposing to C. difficile intestinal colonisation. The pathogenicity of C. difficile is m...

C Denève, C Janoir, I Poilane, C Fantinato, A Collignon (2009) Int J Antimicrob Agents 33 Suppl 1: S24-S28

Effects of subinhibitory concentrations of antibiotics on colonization factor expression by moxifloxacin-susceptible and moxifloxacin-resistant Clostridium difficile strains.

2011-10-13T09:21:40Z

Recent outbreaks of Clostridium difficile infection have been related to the emergence of the NAP1/027 epidemic strain. This strain demonstrates increased virulence and resistance to the C-8-methoxyfluoroquinolones gatifloxacin and moxifloxacin. These antibiotics have been implicated as major C. difficile infection-inducing agents. We investigated by real-time reverse transcription-PCR the impact ...

Cécile Denève, Sylvie Bouttier, Bruno Dupuy, Frédéric Barbut, Anne Collignon, Claire Janoir (2009) Antimicrob Agents Chemother 53: 12 5155-5162

Antibiotics involved in Clostridium difficile-associated disease increase colonization factor gene expression.

2011-10-13T09:21:40Z

Clostridium difficile is the most common cause of antibiotic-associated diarrhoea. Antibiotics are presumed to disturb the normal intestinal microbiota, leading to depletion of the barrier effect and colonization by pathogenic bacteria. This first step of infection includes adherence to epithelial cells. We investigated the impact of various environmental conditions in vitro on the expression of g...

Cécile Denève, Claudine Deloménie, Marie-Claude Barc, Anne Collignon, Claire Janoir (2008) J Med Microbiol 57: Pt 6 732-738

Diminished intestinal colonization by Clostridium difficile and immune response in mice after mucosal immunization with surface proteins of Clostridium difficile.

2011-10-13T09:22:54Z

Clostridium difficile pathogenesis is mainly due to toxins A and B. However, the first step of pathogenesis is the colonization process. We evaluated C. difficile surface proteins as vaccine antigens to diminish intestinal colonization in a human flora-associated mouse model. First, we used the flagellar cap protein FliD of C. difficile, in order to test several immunization routes: intranasal, re...

Séverine Péchiné, Claire Janoir, Hélène Boureau, Aude Gleizes, Nicolas Tsapis, Sandra Hoys, Elias Fattal, Anne Collignon (2007) Vaccine 25: 20 3946-3954

Cwp84, a surface-associated protein of Clostridium difficile, is a cysteine protease with degrading activity on extracellular matrix proteins.

2011-10-13T09:21:40Z

Clostridium difficile pathogenicity is mediated mainly by its A and B toxins, but the colonization process is thought to be a necessary preliminary step in the course of infection. The aim of this study was to characterize the Cwp84 protease of C. difficile, which is highly immunogenic in patients with C. difficile-associated disease and is potentially involved in the pathogenic process. Cwp84 was...

Claire Janoir, Séverine Péchiné, Charlotte Grosdidier, Anne Collignon (2007) J Bacteriol 189: 20 7174-7180

Molecular characterization of Clostridium difficile clinical isolates in a geriatric hospital.

2011-10-13T09:22:54Z

The discriminatory potential of a combination of various typing methods was evaluated on a set of 21 Clostridium difficile isolates obtained from symptomatic patients hospitalized in a geriatric unit and 7 non-toxigenic isolates from the same hospital. Isolates were firstly serotyped and toxinotyped. Of the 28 isolates, 19 belonged to serogroup A. PCR-ribotyping and PCR-RFLP on the fliC and slpA g...

Isabelle Poilane, Christel Humeniuk-Ainouz, Isabelle Durand, Claire Janoir, Philippe Cruaud, Michel Delmée, Michel R Popoff, Anne Collignon (2007) J Med Microbiol 56: Pt 3 386-390

Variability of Clostridium difficile surface proteins and specific serum antibody response in patients with Clostridium difficile-associated disease.

2011-10-13T09:22:54Z

Pathogen attachment is a crucial early step in mucosal infections. This step is mediated by important virulence factors, such as surface proteins. Clostridium difficile surface proteins have been identified as (i) adhesins (the flagellar cap protein FliD; the flagellin FliC; and the cell wall protein Cwp 66 with a two domain-structure [Cw 66 N-terminal and Cwp 66 C-terminal domains]) and (ii) prot...

Séverine Péchiné, Claire Janoir, Anne Collignon (2005) J Clin Microbiol 43: 10 5018-5025

Immunological properties of surface proteins of Clostridium difficile.

2011-10-13T09:22:54Z

Sera from patients with Clostridium difficile-associated disease (CDAD) and sera from a control group were analysed by an ELISA to detect antibodies directed against four surface proteins and toxins A and B of C. difficile. The surface proteins were the flagellar cap protein FliD, the flagellin FliC, the adhesin Cwp66 divided into two domains, Cwp66-Nterminal and Cwp66-Cterminal, and the fibronect...

Séverine Péchiné, Aude Gleizes, Claire Janoir, Roseline Gorges-Kergot, Marie-Claude Barc, Michel Delmée, Anne Collignon (2005) J Med Microbiol 54: Pt 2 193-196

Effect of amoxicillin-clavulanic acid on human fecal flora in a gnotobiotic mouse model assessed with fluorescence hybridization using group-specific 16S rRNA probes in combination with flow cytometry.

2011-10-13T09:22:54Z

Predominant groups of bacteria from a human fecal flora-associated mouse model challenged with amoxicillin-clavulanic acid were quantified with fluorescence in situ hybridization combined with flow cytometry using specific 16S rRNA targeted oligonucleotide probes. This approach provides a useful tool with high throughput to evaluate fecal microflora under antibiotic treatment.

Marie Claude Barc, François Bourlioux, Lionel Rigottier-Gois, Céline Charrin-Sarnel, Claire Janoir, Hélène Boureau, Joël Doré, Anne Collignon (2004) Antimicrob Agents Chemother 48: 4 1365-1368

[Characterization of an extracellular protease from Clostridium difficile].

2011-10-13T09:22:54Z

Clostridium difficile is an intestinal pathogen, which produces two main virulence factors, the exotoxins A and B. Other bacterial structures have been implicated in the colonization of the gastrointestinal tract, which is the first step of the pathogenic process. C. difficile expresses adherence factors and also, displays some surface-associated proteolytic activity, which could play a role in th...

C Janoir, J Grénery, M-P Savariau-Lacomme, A Collignon (2004) Pathol Biol (Paris) 52: 8 444-449

Utilization of 16S ribosomal DNA sequencing for diagnosis of septicemia due to Neisseria elongata subsp. glycolytica in a neutropenic patient.

2011-10-13T09:24:11Z

Septicemia due to Neisseria elongata subsp. glycolytica occurs infrequently. We report a case of septicemia in a patient undergoing antimitotic chemotherapy. Gram-negative coccobacilli were isolated from blood cultures. The identity of the isolate by phenotypic methods was uncertain. In contrast, identity was confirmed by 16S ribosomal DNA sequencing, which appeared to be very useful for correct i...

Cecile Hombrouck-Alet, Isabelle Poilane, Claire Janoir-Jouveshomme, Olivier Fain, Philippe Cruaud, Michel Thomas, Anne Collignon (2003) J Clin Microbiol 41: 7 3436-3437

Identification and characterization of a fibronectin-binding protein from Clostridium difficile.

2011-10-13T09:22:54Z

A 68 kDa fibronectin-binding protein (Fbp68) from Clostridium difficile displaying significant homology to several established or putative Fbps from other bacteria was identified. The one-copy gene is highly conserved in C. difficile isolates. Fbp68 was expressed in Escherichia coli in fusion with glutathione S-transferase; the fusion protein and the native Fbp68 were purified. Immunoblot analysis...

Claire Hennequin, Claire Janoir, Marie-Claude Barc, Anne Collignon, Tuomo Karjalainen (2003) Microbiology 149: Pt 10 2779-2787

Transcription and analysis of polymorphism in a cluster of genes encoding surface-associated proteins of Clostridium difficile.

2011-10-13T09:22:54Z

Recent investigations of the Clostridium difficile genome have revealed the presence of a cluster of 17 genes, 11 of which encode proteins with similar two-domain structures, likely to be surface-anchored proteins. Two of these genes have been proven to encode proteins involved in cell adherence: slpA encodes the precursor of the two proteins of the S-layer, P36 and P47, whereas cwp66 encodes the ...

Marie-Pierre Savariau-Lacomme, Carole Lebarbier, Tuomo Karjalainen, Anne Collignon, Claire Janoir (2003) J Bacteriol 185: 15 4461-4470

New mutation in parE in a pneumococcal in vitro mutant resistant to fluoroquinolones.

2011-10-13T09:22:54Z

For an in vitro mutant of Streptococcus pneumoniae selected on moxifloxacin four- to eightfold-increased MICs of new fluoroquinolones, only a twofold-increased MIC of ciprofloxacin, and a twofold-decreased MIC of novobiocin were observed. This phenotype was conferred by two mutations: Ser81Phe in GyrA and a novel undescribed His103Tyr mutation in ParE, outside the quinolone resistance-determining ...

C Janoir, E Varon, M D Kitzis, L Gutmann (2001) Antimicrob Agents Chemother 45: 3 952-955

ParC and GyrA may be interchangeable initial targets of some fluoroquinolones in Streptococcus pneumoniae.

2011-10-13T09:22:54Z

To evaluate the role of known topoisomerase IV and gyrase mutations in the fluoroquinolone (FQ) resistance of Streptococcus pneumoniae, we transformed susceptible strain R6 with PCR-generated fragments encompassing the quinolone resistance-determining regions (QRDRs) of parC or gyrA from different recently characterized FQ-resistant mutants. Considering the MICs of FQs and the GyrA and/or ParC mut...

E Varon, C Janoir, M D Kitzis, L Gutmann (1999) Antimicrob Agents Chemother 43: 2 302-306

In vitro exchange of fluoroquinolone resistance determinants between Streptococcus pneumoniae and viridans streptococci and genomic organization of the parE-parC region in S. mitis.

2011-10-13T09:22:54Z

Transfer of fluoroquinolone (FQ) resistance determinants between Streptococcus pneumoniae and viridans streptococci was explored by transformation in vitro. One-step FQ-resistant parC mutants were selected, and resistance could be transferred from DNA from S. oralis, S. mitis, S. sanguis, and S. constellatus to S. pneumoniae, with frequencies of 10(-3) to <10(-7) in correlation with the homologies...

C Janoir, I Podglajen, M D Kitzis, C Poyart, L Gutmann (1999) J Infect Dis 180: 2 555-558

Active efflux as a mechanism of resistance to ciprofloxacin in Streptococcus pneumoniae.

2011-10-13T09:22:54Z

The accumulation of fluoroquinolones (FQs) was studied in a FQ-susceptible laboratory strain of Streptococcus pneumoniae (strain R6). Uptake of FQs was not saturable, was rapidly reversible, and appeared to occur by passive diffusion. In the presence of glucose, which energizes bacteria, the uptake of FQs decreased. Inhibitors of the proton motive force and ATP synthesis increased the uptake of FQ...

V Zeller, C Janoir, M D Kitzis, L Gutmann, N J Moreau (1997) Antimicrob Agents Chemother 41: 9 1973-1978

High-level fluoroquinolone resistance in Streptococcus pneumoniae requires mutations in parC and gyrA.

2011-10-13T09:22:54Z

The mechanism of high-level fluoroquinolone resistance was studied in strains of Streptococcus pneumoniae, either selected in vitro or isolated from clinical samples. By using DNA from these high-level-resistant strains, low-level-resistant transformants (MIC of pefloxacin, > or = 32 micrograms/ml; MIC of ciprofloxacin, 4 micrograms/ml; MIC of sparfloxacin, 0.50 micrograms/ml) were obtained at hig...

C Janoir, V Zeller, M D Kitzis, N J Moreau, L Gutmann (1996) Antimicrob Agents Chemother 40: 12 2760-2764