Agnès Rosenau

University of Tours, Tours, Centre, France

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Publications (21)75.85 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: We developed a PCR method with outward Insertion Sequence-specific and -unrelated primers to identify IS1548 targets in the genome of unsequenced Streptococcus agalactiae strains. Our rapid and easy method allowed the identification of previously known but also of yet unnoticed integration sites in the three clinical isolates tested.
    Journal of microbiological methods 04/2013; · 2.43 Impact Factor
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    ABSTRACT: The prevalence of the insertion sequence IS1548 is strongly linked to clonal complex 19 Streptococcus agalactiae strains associated with neonatal meningitis and endocarditis. We previously reported that IS1548 insertion upstream of lmb is involved in stronger binding of a S. agalactiae meningitic strain to laminin. A few other IS1548 insertion sites were also identified by others. In this study, we analyzed IS1548 described target sites in S. agalactiae and showed that most of them are linked to zinc-responsive genes. Moreover, we identified two not yet described IS1548 insertion sites in the adcRCB operon encoding the main regulator of zinc homeostasis and subunits of a zinc ABC transporter. We also identified two conserved motifs of 8 and 10 bp close to IS1548 insertion sites. These motifs representing potential IS1548 targets were found upstream of several S. agalactiae ORFs. One of these predicted IS1548 targets was validated experimentally, allowing the identification of an IS1548 insertion site upstream of murB in all of the clonal complex 19 strains tested. The possible effects of these insertions on the virulence of the strains are discussed. © 2013 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.
    FEMS Microbiology Letters 01/2013; · 2.05 Impact Factor
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    ABSTRACT: Serotype III group B Streptococcus (GBS) is the major cause of neonatal meningitis, but the risk of infection in the colonized neonates is variable. Capsular sialic acid (Sia), whose synthesis is encoded by neu genes, appears to be a major virulence factor in several bacterial species able to reach the cerebrospinal fluid. Therefore, variations of Sia expression related to the genetic diversity of strains may have an impact on the risk of meningitis in colonized neonates. We characterized by MLST the phylogenetic diversity of 64 serotype III GBS strains isolated from vaginal flora and randomly selected. These strains mostly belonged to three major sequence types (STs): ST1 (11%), ST17 (39%) and ST19 (31%). The genetic diversity of strains of these lineages, characterized by PFGE, allowed the selection of 17 representative strains, three ST1, six ST17 and eight ST19, with NEM316 as reference, in order to evaluate (i) by quantitative RT-PCR, the level of transcription of the neuD gene as a marker for the transcription of neu genes and (ii) by enzymological analysis, the expression of Sia. The mean transcription level of neuD was higher for ST17 strains than for ST1 and ST19 strains in the early, mid- and late exponential growth phases, and was maximum in the early exponential growth phase for ST17 strains and in the mid-exponential growth phase for ST1 and ST19 strains. Mean Sia concentration was higher for ST17 than for ST1 and ST9 strains in all three growth phases. For the total population, Sia concentration varied notably in the stationary phase, from 0.38 to 9.30 nmol per 10(8) viable bacteria, with a median value of 2.99 nmol per 10(8) bacteria. All ST17 strains, only one-third of the ST19 strains and none of the ST1 strains had Sia concentrations higher than the median Sia concentration. Therefore, differences in the level of expression of Sia by strains of the major serotype III GBS phylogenetic lineages might be one of the factors that explain the leading role of ST17 strains in neonatal meningitis.
    Microbiology 08/2011; 157(Pt 12):3282-91. · 3.06 Impact Factor
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    ABSTRACT: Multilocus sequence typing (MLST) is currently the reference method for genotyping Streptococcus agalactiae strains, the leading cause of infectious disease in newborns and a major cause of disease in immunocompromised children and adults. We describe here a genotyping method based on multiple locus variable number of tandem repeat (VNTR) analysis (MLVA) applied to a population of S. agalactiae strains of various origins characterized by MLST and serotyping. We studied a collection of 186 strains isolated from humans and cattle and three reference strains (A909, NEM316 and 2603 V/R). Among 34 VNTRs, 6 polymorphic VNTRs loci were selected for use in genotyping of the bacterial population. The MLVA profile consists of a series of allele numbers, corresponding to the number of repeats at each VNTR locus. 98 MLVA genotypes were obtained compared to 51 sequences types generated by MLST. The MLVA scheme generated clusters which corresponded well to the main clonal complexes obtained by MLST. However it provided a higher discriminatory power. The diversity index obtained with MLVA was 0.960 compared to 0.881 with MLST for this population of strains. The MLVA scheme proposed here is a rapid, cheap and easy genotyping method generating results suitable for exchange and comparison between different laboratories and for the epidemiologic surveillance of S. agalactiae and analyses of outbreaks.
    BMC Microbiology 07/2011; 11:171. · 3.10 Impact Factor
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    ABSTRACT: Group B streptococcus (GBS) strains with the highest ability to bind to human fibrinogen belong to the highly invasive clonal complex (CC) 17. To investigate the fibrinogen-binding mechanisms of CC17 strains, we determined the prevalence of fibrinogen-binding genes (fbsA and fbsB), and fbs regulator genes (rogB encoding an fbsA activator, rovS encoding an fbsA repressor and rgf encoding a two-component system [TCS] whose role on fbs genes was not determined yet) in a collection of 134 strains representing the major CCs of the species. We showed that specific gene combinations were related to particular CCs; only CC17 strains contained the fbsA, fbsB, and rgf genes combination. Non polar rgfAC deletion mutants of three CC17 serotype III strains were constructed. They showed a 3.2- to 5.1-fold increase of fbsA transcripts, a 4.8- to 6.7-fold decrease of fbsB transcripts, and a 52% to 68% decreased fibrinogen-binding ability, demonstrating that the RgfA/RgfC TCS inhibits the fbsA gene and activates the fbsB gene. The relative contribution of the two fbs genes in fibrinogen-binding ability was determined by constructing isogenic fbsA, fbsB, deletion mutants of the three CC17 strains. The ability to bind to fibrinogen was reduced by 49% to 57% in ΔfbsA mutants, and by 78% to 80% in ΔfbsB mutants, suggesting that FbsB protein plays a greater role in the fibrinogen-binding ability of CC17 strains. Moreover, the relative transcription level of fbsB gene was 9.2- to 12.7-fold higher than that of fbsA gene for the three wild type strains. Fibrinogen-binding ability could be restored by plasmid-mediated expression of rgfAC, fbsA, and fbsB genes in the corresponding deletion mutants. Thus, our results demonstrate that a specific combination of fbs genes and fbs regulator genes account for the high fibrinogen-binding ability of CC17 strains that may participate to their enhanced invasiveness for neonates as compared to strains of other CCs.
    PLoS ONE 01/2011; 6(2):e14658. · 3.73 Impact Factor
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    ABSTRACT: Group B streptococcus (GBS) is the main cause of neonatal sepsis and meningitis. Bacterial surface proteins play a major role in GBS binding to and invasion of different host surfaces. The scpB and lmb genes, coding for fibronectin-binding and laminin-binding surface proteins, are present in almost all human GBS isolates. The scpB-lmb intergenic region is a hot spot for integration of two mobile genetic elements (MGEs): the insertion element IS1548 or the group II intron GBSi1. We studied the structure of scpB-lmb intergenic region in 111 GBS isolates belonging to the intraspecies major clonal complexes (CCs). IS1548 was mostly found (72.2%) in CC19 serotype III strains recovered more specifically (92.3%) from neonatal meningitis. GBSi1 was principally found (70.6%) in CC17 strains, mostly (94.4%) of serotype III, but also (15.7%) in CC19 strains, mostly (87.5%) of serotype II. No MGE was found in most strains of the other CCs (76.0%), notably CC23, CC10 and CC1. Twenty-six strains representing these three genetic configurations were selected to investigate the transcription and expression levels of scpB and lmb genes. Quantitative RT-PCR showed that lmb transcripts were 5.0- to 9.6-fold higher in the group of strains with IS1548 than in the other two groups of strains (P<0.001). Accordingly, the binding ability to laminin was 3.8- to 6.6-fold higher in these strains (P< or =0.001). Moreover, Lmb amount expressed on the cell surface was 2.4- to 2.7-fold greater in these strains (P<0.001). By contrast, scpB transcript levels and fibronectin binding ability were similar in the three groups of strains. Deletion of the IS1548 sequence between scpB and lmb genes in a CC19 serotype III GBS strain substantially reduced the transcription of lmb gene (13.5-fold), the binding ability to laminin (6.2-fold), and the expression of Lmb protein (5.0-fold). These data highlight the importance of MGEs in bacterial virulence and demonstrate the up-regulation of lmb gene by IS1548; the increased lmb gene expression observed in CC19 serotype III strains with IS1548 may play a role in their ability to cause neonatal meningitis and endocarditis.
    PLoS ONE 01/2010; 5(5):e10794. · 3.73 Impact Factor
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    ABSTRACT: The aim of this study is to identify the molecular characteristics of erythromycin-resistant (Erm(r)) Streptococcus agalactiae strains and to correlate with the clinical origin of strains. From 711 S. agalactiae strains, 119 Erm(r) strains (17%) were collected, serotyped and screened for macrolide resistance genes. The genetic relationship between strains was established by the PFGE analysis. Strains were tested for the group II intron GBSi1 downstream of the scpB gene, IS1548 in the hylB gene, four prophage DNA fragments and a lineage defined by multilocus sequence typing as ST-17. Erythromycin resistance involved 8% of serotype Ia, 15% of serotype Ib, 9% of serotype II, 16% of serotype III, 31% of serotype IV and 35% of serotype V. The prevalence of Erm(r) strains was higher among strains isolated from the gastric fluid of neonates (33%) than in those isolated from bacteraemia and meningitis during early-onset disease (EOD) or late-onset disease (7% and 11%) (P = 0.001). In serotype III, Erm(r) strains were more frequent in vaginal carriage (22%) and colonized neonates (18%) than in EOD (0%) (P = 0.03). The mef(A) gene was the most common in serotype Ia (55%), the erm(A) gene in serotype Ib (75%) and the erm(B) gene in the other serotypes (56% to 75%). All resistant strains with IS1548 also had the erm(B) gene. Erm(r) strains were not randomly distributed in the different PFGE genogroups, and 11% had the GBSi1 intron, 37% had at least one prophage DNA fragment and 7% belonged to ST-17. Erythromycin resistance varied according to the clinical origin, serotype and molecular characteristics of S. agalactiae strains.
    Journal of Antimicrobial Chemotherapy 10/2008; 62(6):1227-33. · 5.34 Impact Factor
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    ABSTRACT: We sought an explanation for epidemiological changes in Streptococcus agalactiae infections by investigating the link between ecological niches of the bacterium by determining the prevalence of 11 mobile genetic elements. The prevalence of nine of these elements differed significantly according to the human or bovine origin of the isolate. Correlating this distribution with the phylogeny obtained by multilocus sequence analysis, we observed that human isolates harboring GBSi1, a clear marker of the bovine niche, clustered in clonal complex 17. Our results are thus consistent with the emergence of this virulent human clone from a bovine ancestor.
    Applied and Environmental Microbiology 08/2007; 73(14):4668-72. · 3.95 Impact Factor
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    ABSTRACT: The ability of 111 Streptococcus agalactiae strains to bind to human fibrinogen was quantified. We correlated the percentages of bacteria that bound to immobilized fibrinogen with fibrinogen-binding (fbs) gene characteristics of strains and with clinical origin, serotypes, and phylogenetic positions of strains. Percentages varied from 0.4 to 29.9%. Fifty-five strains (49.5%) had the fbsB gene sensu stricto described by Gutekunst et al. (Infect. Immun., 72:3495-3504, 2004), allowing adhesion to human fibrinogen, and all of the other strains had an fgag variant gene. Ninety strains (81.1%) had a fbsA gene and 55 of them also had the fbsB gene. The other 21 strains (18.9%) had a truncated form of fbsA without the fbsB gene sensu stricto. The numbers of 48-nucleotide repeat sequences (rs) in the fbsA gene varied from 2 to 26. The population of strains with the highest ability to bind to human fibrinogen significantly more frequently had the fbsB gene sensu stricto and 4 to 7 rs in the fbsA gene (P < 0.05). However, the single strain that carried the highest number of rs (26 rs) in the fbsA gene showed high fibrinogen-binding activity (24.3%). Strains exhibiting significantly higher levels of binding to human fibrinogen belonged to a phylogenetic group of strains associated with neonatal meningitis, currently known as the ST-17 clone, that is mostly composed of serotype III strains. These findings indicate that S. agalactiae strains possess a wide variety of fbs gene content that markedly influences the ability of strains to bind to human fibrinogen. Variations in the configuration and the expression of the Fbs proteins may therefore partly explain the variability of virulence in S. agalactiae species.
    Infection and Immunity 03/2007; 75(3):1310-7. · 4.07 Impact Factor
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    ABSTRACT: The abilities of 151 Streptococcus agalactiae strains to oxidize 95 carbon sources were studied using the Biolog system. Two populations were constituted: one with a high risk of causing meningitis (HR group; 63 strains), and the other with a lower risk of causing meningitis (LR group; 46 strains). Strains belonging to the HR group were significantly less able to use four carbon sources, i.e., alpha-D-glucose-1-phosphate, D-ribose, beta-methyl-D-glucoside, and D,L-alpha-glycerol phosphate, than strains from the LR group (P <or= 0.004). Moreover, strains in the HR group significantly more frequently possessed one of several mobile genetic elements or genome deletions previously shown to be associated with strains responsible for neonatal meningitis than strains in the LR group (P < 0.001). These findings suggest that genetic disruption might have occurred in virulent clones of S. agalactiae. Fifteen biotypes (B1 to B15) were identified from the results of oxidation of the four carbon sources, of which six (B1 to B6) included 92% of the isolates belonging to the HR group. Strains of biotypes B1 to B6 are thus 13 times more likely to be able to invade the central nervous system of neonates than strains of biotypes B7 to B15. In addition, 86% of strains recently associated with neonatal meningitis (42 strains studied) were identified as being of biotypes B1 to B6. Identification of particular S. agalactiae biotypes may therefore be one of the criteria to assist clinicians in assessing the level of risk of neonatal meningitis when a mother and/or her neonate is colonized with S. agalactiae.
    Journal of Clinical Microbiology 09/2006; 44(9):3245-50. · 4.07 Impact Factor
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    ABSTRACT: We identified-by randomly amplified polymorphic DNA (RAPD) analysis at the population level followed by DNA differential display, cloning, and sequencing-three prophage DNA fragments (F5, F7, and F10) in Streptococcus agalactiae that displayed significant sequence similarity to the DNA of S. agalactiae and Streptococcus pyogenes. The F5 sequence aligned with a prophagic gene encoding the large subunit of a terminase, F7 aligned with a phage-associated cell wall hydrolase and a phage-associated lysin, and F10 aligned with a transcriptional regulator (ArpU family) and a phage-associated endonuclease. We first determined the prevalence of F5, F7, and F10 by PCR in a collection of 109 strains isolated in the 1980s and divided into two populations: one with a high risk of causing meningitis (HR group) and the other with a lower risk of causing meningitis (LR group). These fragments were significantly more prevalent in the HR group than in the LR group (P < 0.001). Our findings suggest that lysogeny has increased the ability of some S. agalactiae strains to invade the neonatal brain endothelium. We then determined the prevalence of F5, F7, and F10 by PCR in a collection of 40 strains recently isolated from neonatal meningitis cases for comparison with the cerebrospinal fluid (CSF) strains isolated in the 1980s. The prevalence of the three prophage DNA fragments was similar in these two populations isolated 15 years apart. We suggest that the prophage DNA fragments identified have remained stable in many CSF S. agalactiae strains, possibly due to their importance in virulence or fitness.
    Journal of Clinical Microbiology 03/2006; 44(3):1049-58. · 4.07 Impact Factor
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    ABSTRACT: The prevalence of insertion sequences IS1548, IS861, IS1381, and ISSa4 and of the group II intron GBSi1 within Streptococcus agalactiae human isolates strongly correlates with the genetic lineages obtained by multilocus sequence typing. Our results yielded an evolutionary scheme for the acquisition of these genetic elements linked to the ecosystems from which the isolates were obtained.
    Journal of Bacteriology 10/2005; 187(17):6248-52. · 3.19 Impact Factor
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    ABSTRACT: To correlate the presence of mobile genetic elements (MGE) to the evolution of Streptococcus agalactiae, we first evaluated the distribution of five MGEs (IS1548, IS861, IS1381, ISSa4 and GBSi1) in a representative collection of strains. The number of copies of each MGE was also determined for each strain, together with the relative positions of the copies on Southern blot patterns. We thus correlated these results with those obtained by a phylogenetic analysis performed by multilocus sequence typing (MLST) using the nucleotide sequences of seven housekeeping genes, which identified five groups of strains. Our results show that 76.9% of the strains possessed IS861 (16 Southern blot patterns each showing one to ten copies of this MGE), 71.2% possessed IS1381 (31 patterns each showing one to ten copies), 36.5% possessed IS1548 (15 patterns each showing one to nine copies), 30.8% possessed GBSi1 (5 patterns each showing one to 12 copies) and 7.7% possessed ISSa4 (4 patterns, each showing three to 20 copies). Simultaneous analysis of the presence or absence of the five MGEs revealed nine combinations corresponding to nine genetic variants. We observed strong congruence between the MLST groups and the distribution of the genetic variants. Given the prevalence of the MGEs, the number of MGE copies and the number of patterns, we propose an evolutionary hypothesis to explain the chronological order of MGE acquisition during S. agalactiae evolution. The putative common oldest ancestor may have harboured IS1381 and IS861; IS1548 may have been acquired thereafter. The most recent acquisitions appear to have been GBSi1 and ISSa4, which are present in the smallest number of strains.
    Pathologie Biologie - PATHOL BIOL. 01/2005;
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    ABSTRACT: Intergenic dyad sequences (IDS) are short repeated elements that have been described for several Haemophilus genomes and for only two other bacterial genera. We developed a repetitive-element sequence-based PCR using an IDS-specific primer as a typing method (IDS-PCR) for nonencapsulated Haemophilus strains and compared this technique with pulsed-field gel electrophoresis (PFGE) of DNA restricted with SmaI. IDS-PCR was rapid, easy to perform, and reproducible, with a high discriminatory capacity for nontypeable Haemophilus influenzae (NTHI) strains. The 69 NTHI strains tested generated 65 different banding patterns. Epidemiologically related strains gave similar or identical fingerprints, and all of the unrelated strains except two showed different patterns. These results were in agreement with those obtained by PFGE. For 20 genital strains usually identified as being biotype IV NTHI and belonging to a cryptic genospecies of Haemophilus with remarkable genetic homogeneity, four bands were significantly present and six bands were significantly absent from the fingerprints. The 20 strains were gathered in 11 closely related profiles, whereas PFGE provided no band when DNA was treated with SmaI. IDS-PCR improved the differentiation previously obtained within this species by ribotyping and multilocus enzyme electrophoresis. Our findings suggest that IDS-PCR is a rapid, reliable, and discriminatory method for typing NTHI strains and is currently the most efficient method for distinguishing strains within the cryptic genospecies of HAEMOPHILUS:
    Journal of Clinical Microbiology 09/2003; 41(8):3473-80. · 4.07 Impact Factor
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    ABSTRACT: We analyzed the LKP fimbrial gene clusters of six piliated strains of a cryptic genospecies of Haemophilus isolated from the genital tracts of adult patients (five strains) and from an infected neonate. In a group of 19 genital strains, LKP-like genes have been found in only these 6 strains. In addition to the ghfA, ghfD, and ghfE genes previously described, we characterized two genes, designated ghfB and ghfC, encoding the putative chaperone and assembly platform proteins. All six strains had a complete and unique LKP-like gene cluster consisting of the five genes ghfA to ghfE, homologous to genes hifA to hifE of Haemophilus influenzae. The sequences of the coding and intergenic regions of the ghf clusters of the six strains were remarkably homologous. Unlike hif clusters, which are inserted between purE and pepN, the ghf cluster was inserted between purK and pepN on the chromosome. Analysis of the flanking regions of the ghf cluster identified a large deletion, identical in the 5' end regions of all strains, including the whole purE gene and much of the purK gene. Ultrastructural observations, an attempt at enriching LKP fimbriae, and hemagglutination experiments demonstrated that none of the strains had LKP-type fimbriae. Nevertheless, reverse transcription (RT)-PCR showed that ghf genes were transcribed in four of the six strains. Sequencing of the intergenic ghfA-ghfB regions, including the ghf gene promoters, showed that the absence of transcripts in the remaining two strains was due to a decrease in the number of TA repeats (4 or 9 repeats rather than 10) between the -10 and -35 boxes of the two overlapping and divergent promoters. The other four strains, which had ghf transcripts, had the optimal 10 TA repeats (one strain) or 5 repeats associated with putative alternative -35 boxes (three strains). The absence of 10 repeated palindromic sequences of 44 or 45 nucleotides upstream of ghfB induces an increased instability of mRNA, as quantified by real-time RT-PCR, and may explain why the LKP fimbrial gene cluster is not expressed in these strains.
    Infection and Immunity 11/2002; 70(10):5438-45. · 4.07 Impact Factor
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    ABSTRACT: A plasmid-encoded extended-spectrum TEM beta-lactamase with a pI of 5.5 was detected in a Capnocytophaga ochracea clinical isolate. The bla gene was associated with a strong TEM-2 promoter and was derived from bla(TEM-1a) with a single-amino-acid substitution: Glu(104)-->Lys, previously assigned to TEM-17, which is thus the first TEM beta-lactamase to be reported in the phylum Flavobacter-Bacteroides.
    Antimicrobial Agents and Chemotherapy 04/2000; 44(3):760-2. · 4.57 Impact Factor
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    ABSTRACT: Nineteen isolates belonging to a cryptic genospecies of Haemophilus (referred to here as genital strains) isolated from genital tract infections (6 strains) and from neonatal infections (13 strains) were studied for fimbrial genes. Sixteen strains exhibit peritrichous fimbriae observed by electron microscopy. By PCR with primers corresponding to the extreme ends of the Haemophilus influenzae type b (Hib) hifA and hifD genes and Southern blotting, a hifA-like gene (named ghfA) and a hifD-like gene (named ghfD) were identified in 6 of the 19 strains. Five of these six strains were from the genital tracts of adults, and one was from a neonate. For each gene, the nucleotide sequence was identical for the six strains. A hifE-like gene (named ghfE) was amplified from only one of the 19 genital strains of Haemophilus, but the ghfE probe gave a signal in Southern hybridization with the five other strains positive for ghfA and ghfD. Therefore, these strains may carry a ghfE-like gene. The Hib fimbrial gene cluster is located between the purE and pepN genes as previously described. For the 13 genital Haemophilus strains that lack fimbrial genes, this region corresponds to a noncoding sequence. Another major fimbrial gene designated the fimbrin gene was previously identified in a nontypeable H. influenzae strain. A fimbrin-like gene was identified for all of our 19 genital strains. This gene is similar to the ompP5 gene of many Haemophilus strains. Therefore, other, unidentified genes may explain the piliation observed in electron microscopy on genital Haemophilus strains which do not possess LKP-like fimbrial genes. Fimbrial genes were significantly associated with strains isolated from the genital tract. They may confer on the strain the ability to survive in the genital tract.
    Infection and Immunity 02/1999; 67(1):8-15. · 4.07 Impact Factor
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    ABSTRACT: A collection of 54 unrelated Streptococcus agalactiae strains isolated from cerebrospinal fluid samples from neonates and 60 unrelated strains isolated from carriers that had been previously studied by multilocus enzyme electrophoresis (R. Quentin, H. Huet, F.-S. Wang, P. Geslin, A. Goudeau, and R. K. Selander, J. Clin. Microbiol. 33:2576-2581, 1995) were characterized by randomly amplified polymorphic DNA (RAPD) assay. Four primers, 5'AGGGGGTTCC3', 5'AACGCGCAAC3', 5'GCATCAATCT3', and 5'AGTCGGGTGG3', named OPS16, AP42, A4, and OPS11, respectively, were selected from 29 primers tested. This investigation identified 71 RAPD types. The three families of strains defined by multilocus enzyme electrophoresis analysis, which contain most of the cerebrospinal fluid isolates, were also identified by clustering analysis of RAPD data. Each of these three groups exhibits specific RAPD patterns or fragments. The discriminatory power of the RAPD typing method was also evaluated. The simplest typing scheme was obtained by the combination of RAPD typing done with primers AP42 and OPS11 and serotyping (index of discrimination, 0.97).
    Journal of Clinical Microbiology 11/1997; 35(10):2573-9. · 4.07 Impact Factor
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    ABSTRACT: The genetic diversity of a collection of 54 unrelated Streptococcus agalactiae strains isolated from the cerebrospinal fluid of neonates and of 60 unrelated carrier strains was evaluated by investigating the restriction fragment length polymorphism of the rRNA gene region. Three restriction enzymes were selected for use: PstI, HindIII, and CfoI. Clustering analysis revealed two phylogenetic groups of strains with 40% divergence. Group I contained two clusters, A and B, and group II contained three clusters, C, D, and E. Strains of serotype Ia were mostly distributed in cluster A, and strains of serotype Ib were mostly distributed in cluster E. Serotype III isolates did not cluster. Nevertheless, 37 of 39 isolates belonging to cluster B were serotype III. With HindIII, two rRNA gene banding patterns characterized 38 of the 39 strains of cluster B, which represents a high-virulence group. In addition, two rRNA gene banding patterns with each enzyme and/or a pair of CfoI fragments of 905 and 990 bp identified 81% of the invasive strains. On account of the genetic homogeneity of the cerebrospinal fluid strains, ribotyping is a powerful typing method for investigation of nosocomial or epidemic invasive infections only when all three enzymes are used or when PstI and HindIII or PstI and CfoI are combined with serotyping (index of discrimination, > 0.95).
    Journal of Clinical Microbiology 12/1996; 34(11):2741-7. · 4.07 Impact Factor
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    ABSTRACT: Previous genetic analysis of Haemophilus influenzae strains isolated from genital and neonatal infections identified a group of biotype IV that constitutes a cryptic genospecies only distantly related to H. influenzae and H. Haemolyticus. Small-subunit rRNA genes of two representative strains of this genital Haemophilus genospecies (strains 16N and 2406) were sequenced. The analysis indicated that these strains form a monophyletic unit with H. haemolyticus and H. influenzae biogroups Influenzae and Aegyptius and are more closely related to H. haemolyticus than to H. influenzae biogroups Influenzae and Aegyptius. 16S rRNA gene sequences were used to formulate primers for PCR-based identification of cryptic genital Haemophilus organisms. A 242-bp fragment was amplified from strains belonging to the genital Haemophilus genospecies but not from strains of 12 other Haemophilus species, including strains of H. influenzae biotype IV sensu stricto.
    Journal of Clinical Microbiology 07/1996; 34(6):1380-5. · 4.07 Impact Factor

Publication Stats

232 Citations
75.85 Total Impact Points

Institutions

  • 1999–2011
    • University of Tours
      Tours, Centre, France
  • 2000–2007
    • Centre Hospitalier Universitaire de Tours
      Tours, Centre, France
  • 2006
    • Erasmus MC
      • Department of Medical Microbiology and Infectious Diseases
      Rotterdam, South Holland, Netherlands
  • 1993–1997
    • French National Centre for Scientific Research
      Lutetia Parisorum, Île-de-France, France
  • 1996
    • Centre Hospitalier Intercommunal Creteil
      Créteil, Île-de-France, France