Céline Plainvert

Université René Descartes - Paris 5, Lutetia Parisorum, Île-de-France, France

Are you Céline Plainvert?

Claim your profile

Publications (12)43.06 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Streptococcus pyogenes (group A Streptococcus, GAS) causes a wide variety of diseases ranging from mild non-invasive to severe invasive infections. Mutations in regulatory components have been implicated in the switch from colonization to invasive phenotypes. Inactivation of the sil locus, composed of six genes encoding a quorum sensing complex, gives rise to a highly invasive strain. However, studies conducted on limited collections of GAS strains suggested that sil prevalence is around 15 %; furthermore, whereas correlation between sil presence and genetic background was suggested, no link between the presence of a functional sil and the invasive status was assessed. We established a collection of 637 non-redundant strains covering all emm genotypes present in France and of known clinical history, 68%, 22% and 10% were from invasive, non-invasive infections and asymptomatic carriage, respectively. Among the 637 strains, 206 were sil positive. The prevalence of the sil locus varied according to the emm genotype, being present in more than 85 % of the emm4, emm18, emm32, emm60, emm87 and emm90 strains and absent from all emm1, emm28 and emm89 strains. A random selection based on 2009 French epidemiological data indicated that 16% of GAS strains are sil positive. Moreover, due to mutations leading to truncated proteins, only 9% of GAS strains harbor a predicted functional sil system. No correlation was observed between the presence or absence of a functional sil locus and the strain invasiveness status.
    Journal of clinical microbiology 03/2014; · 4.16 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Group A Streptococcus (GAS) infections remain a significant health care problem due to high morbidity and mortality associated with GAS diseases, along with their increasing worldwide prevalence. Macrophages play a key role in the control and clearance of GAS infections. Moreover, pro-inflammatory cytokines production and GAS persistence and invasion are related. In this study we investigated the correlation between the GAS clinical isolates genotypes, their known clinical history, and their ability to modulate innate immune response. We constituted a collection of 40 independent GAS isolates representative of the emm types currently prevalent in France and responsible for invasive (57.5%) and non-invasive (42.5%) clinical manifestations. We tested phagocytosis and survival in mouse bone marrow-derived macrophages and quantified the pro-inflammatory mediators (IL-6, TNF-α) and type I interferon (INF-β) production. Invasive emm89 isolates were more phagocytosed than their non-invasive counterparts, and emm89 isolates more than the other isolates. Regarding the survival, differences were observed depending on the isolate emm type, but not between invasive and non-invasive isolates within the same emm type. The level of inflammatory mediators produced was also emm type-dependent and mostly invasiveness status independent. Isolates of the emm1 type were able to induce the highest levels of both pro-inflammatory cytokines, whereas emm89 isolates induced the earliest production of IFN-β. Finally, even within emm types, there was a variability of the innate immune responses induced, but survival and inflammatory mediator production were not linked.
    PLoS ONE 01/2014; 9(7):e101464. · 3.73 Impact Factor
  • Philippe Bidet, Céline Plainvert, Stéphane Bonacorsi
    Veterinary Microbiology 12/2013; · 3.13 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We characterized 182 Streptococcus dysgalactiae subsp. equisimilis isolates and analyzed the epidemiological data on the corresponding infections. stG6, stG485, and stG6792 were the 3 most prevalent invasive emm types among the 27 different emm types recovered. High rates of antimicrobial resistance were observed for macrolides (26.4%) and tetracycline (34.6%).
    Journal of clinical microbiology 05/2013; · 4.16 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: M/emm typing, based either on serotyping of the M protein or on sequencing of the emm gene, is a major tool for epidemiological studies of group A streptococci (GAS). In order to simplify M/emm typing, we designed two multiplex polymerase chain reaction (PCR) formats capable of identifying the most frequent GAS M/emm types involved in invasive infections and antimicrobial resistance. A heptaplex PCR procedure was first developed in a conventional format coupled with gel electrophoresis to identify emm types 1, 3, 4, 6, 12, 28, and 89, based on the size of the amplification products. The other method, designed to identify the same seven emm types, together with emm11, was based on a real-time PCR format coupled with high-resolution melting (HRM) analysis, allowing the rapid typing of large strain collections.
    European Journal of Clinical Microbiology 05/2012; 31(10):2817-26. · 3.02 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Toxic shock syndrome (TSS) and septic shock (SS) share many clinical signs of an exacerbated inflammatory response. In this report, we investigated whether TSS presents similar features of delayed immunosuppression as described in SS. Five children with TSS from paediatric intensive care units in a university hospital were monitored. TSS cases were defined by the association of standardized clinical signs of TSS and confirmed by measurement of specific Vbeta expansions corresponding to toxin gene profile of the isolated strains. As in SS, an increased percentage of circulating regulatory T cells (Treg) was observed in patients with TSS. However, in contrast to SS, neither lymphopenia nor decreased HLA-DR expression on monocytes was measured. In conclusion, whereas SS and TSS exhibited similar clinical presentation, the present observation suggests that respective pathophysiological mechanisms induce different immune alterations. Future studies must isolate and better characterize the phenotypic and functional properties of Treg subsets during TSS to understand the mechanisms sustaining their increase, especially the putative role of superantigens.
    FEMS Immunology & Medical Microbiology 05/2012; 66(1):116-9. · 2.68 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Severe invasive group A streptococcal diseases have re-emerged during the past 10-20 years. In order to provide a better insight into the current epidemiological situation in France, we analysed the questionnaires regarding all invasive strains received at the National Reference Center for Streptococci (CNR-Strep) between 2006 and 2010 from patients aged ≥ 18 and characterized them by emm typing, spe gene detection and antibiotic resistance. Among the 1542 invasive GAS strains studied, 78% (n=1206) were from blood cultures, and a streptococcal toxic shock syndrome (STSS) was described in 22% (n=340) of cases, mainly associated with necrotizing fasciitis (NF) and pleuro-pulmonary infections (p<0.001). The in-hospital fatality rate was 15%. A total of 83 different emm types were recovered but the three predominant emm types, representing almost 60% of the isolates, were emm1 (24%), emm28 (17%) and emm89 (15%). The preponderance of each emm type varied according to the year, with a significant constant increase of emm28 strains, whereas emm1 strains, representing approximately 32% of GAS invasive isolates in 2007 and 2008, dropped to <15% in 2010 (p<0.001). The distribution of phage-associated superantigen genes (speA, speC and ssa) was linked to certain emm types. Between 2006 and 2010, the percentage that was macrolide-resistant decreased from 11% to 5%, confirming the trend observed in 2007. Fortunately, emm1 strains associated with the most life-threatening clinical manifestations remain susceptible to all anti-streptococcal antibiotics.
    Clinical Microbiology and Infection 06/2011; 18(7):702-10. · 4.58 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To the Editor: Streptococcus pyogenes, or group A streptococci (GAS), are human pathogens responsible for pharyngitis as well as skin and soft tissue infections. Invasive GAS diseases, including bacteremia, cellulitis, and necrotizing fasciitis, are life-threatening, especially when associated with toxic shock syndrome. Several risk factors for GAS infections are known, such as diabetes, immunosuppression, drug use, and skin lesions (1,2).
    Emerging Infectious Diseases 02/2011; 17(2):315-7. · 6.79 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Since the 1980s, infections due to Streptococcus pyogenes or group A streptococci (GAS) were marked by the increase in invasive infections and the emergence of clones which were resistant to macrolides. Those challenges led the French national reference center for streptococci to enhance the epidemiological survey and the characterization of GAS strains, in collaboration with the National Institute for Public Health Surveillance. Active surveillance is of major importance for implementation of therapeutic and prophylactic guidelines and for evaluation of future streptococcal vaccines.
    Archives de Pédiatrie 11/2009; 17(2):201-8. · 0.36 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: As antibiotic pressure often triggers bacterial resistance, the use of short-duration therapies is increasingly recommended. The objective of the present study was to evaluate both the clinical efficiency and the impact on oral streptococci of a 3 day versus a 7 day amoxicillin therapy for odontogenic infection requiring tooth extraction. On day 0, patients were randomly assigned to a 3 day or 7 day amoxicillin treatment. The tooth was extracted on day 2 and the post-operative follow-up was carried out on day 9. Oral flora was collected on days 0, 9 and 30, and the susceptibility of the streptococci to amoxicillin was determined. The results showed that treatment with amoxicillin for 3 or 7 days had a similar clinical efficiency, and also induced similar selection of oral streptococci with reduced susceptibility to amoxicillin, suggesting that the selection of strains with reduced susceptibility to amoxicillin is a rapid phenomenon, appearing even with short-duration therapies.
    Journal of Medical Microbiology 07/2009; 58(Pt 8):1092-7. · 2.30 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A new Escherichia coli virulent clonal group, O45:K1, belonging to the highly virulent subgroup B2(1) was recently identified in France, where it accounts for one-third of E. coli neonatal meningitis cases. Here we describe the sequence, epidemiology and function of the large plasmid harbored by strain S88, which is representative of the O45:K1 clonal group. Plasmid pS88 is 133,853 bp long and contains 144 protein-coding genes. It harbors three different iron uptake systems (aerobactin, salmochelin, and the sitABCD genes) and other putative virulence genes (iss, etsABC, ompT(P), and hlyF). The pS88 sequence is composed of several gene blocks homologous to avian pathogenic E. coli plasmids pAPEC-O2-ColV and pAPEC-O1-ColBM. PCR amplification of 11 open reading frames scattered throughout the plasmid was used to investigate the distribution of pS88 and showed that a pS88-like plasmid is present in other meningitis clonal groups such as O18:K1, O1:K1, and O83:K1. A pS88-like plasmid was also found in avian pathogenic strains and human urosepsis strains belonging to subgroup B2(1). A variant of S88 cured of its plasmid displayed a marked loss of virulence relative to the wild-type strain in a neonatal rat model, with bacteremia more than 2 log CFU/ml lower. The salmochelin siderophore, a known meningovirulence factor, could not alone explain the plasmid's contribution to virulence, as a salmochelin mutant displayed only a minor fall in bacteremia (0.9 log CFU/ml). Thus, pS88 is a major virulence determinant related to avian pathogenic plasmids that has spread not only through meningitis clonal groups but also human urosepsis and avian pathogenic strains.
    Infection and immunity 04/2009; 77(6):2272-84. · 4.21 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A new highly pathogenic clone of Escherichia coli meningitis strains harboring the unusual serogroup O45 has recently emerged in France. To gain insight into the pathogenicity of this new clone, we investigated the possible role of antigen O45 in the virulence of strain S88 (O45:K1:H7), representative of this emerging clone. We first showed that the S88 O-antigen gene cluster sequence differs from that of O45 in the reference strain E. coli 96-3285, suggesting that the two O45 polysaccharides, while probably sharing a community of epitopes, represent two different antigens. The unique functional organization of the two O-antigen gene clusters and the low DNA sequence homology of the orthologous genes suggest that the two loci originated from a common ancestor and have since undergone multiple recombination events. Phylogenetic analysis based on the flanking gene gnd sequences indicates that the S88 antigen O45 (O45(S88)) gene cluster may have been acquired, at least in part, from another member of the Enterobacteriaceae. Mutagenesis of the O45(S88) antigen gene cluster was used for functional analysis of the loci and revealed the crucial role of the O polysaccharide in S88 virulence in a neonatal rat meningitis model. We also developed a PCR method to specifically identify the O45(S88) antigen gene cluster. Together, our findings suggest that horizontal acquisition of a new O-antigen gene cluster, at least partly from another species, may have been a key event in the emergence and virulence of the E. coli O45:K1:H7 clone in France.
    Journal of bacteriology 01/2008; 189(23):8528-36. · 3.94 Impact Factor

Publication Stats

54 Citations
43.06 Total Impact Points

Institutions

  • 2014
    • Université René Descartes - Paris 5
      Lutetia Parisorum, Île-de-France, France
  • 2013
    • Assistance Publique – Hôpitaux de Paris
      Lutetia Parisorum, Île-de-France, France
  • 2009–2013
    • Paris Diderot University
      Lutetia Parisorum, Île-de-France, France
  • 2012
    • Université Paris Descartes
      • Faculté de Médecine
      Lutetia Parisorum, Île-de-France, France