Marie Titecat

University of Lille Nord de France, Lille, Nord-Pas-de-Calais, France

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Publications (6)14.92 Total impact

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    ABSTRACT: Ruminococcus gnavus is an anaerobic Gram positive coccus that can be found in the gastrointestinal tract of animals and humans. We report a case of septic arthritis caused by R. gnavus that was identified by mass spectrometry and confirmed by 16S rRNA sequencing.
    Anaerobe 10/2014; · 2.02 Impact Factor
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    ABSTRACT: Plague is transmitted by fleas or contaminated aerosols. To successfully produce disease, the causal agent (Yersinia pestis) must rapidly sense and respond to rapid variations in its environment. Here, we investigated the role of two-component regulatory systems (2CSs) in plague because the latter are known to be key players in bacterial adaptation to environmental change. Along with the previously studied PhoP-PhoQ system, OmpR-EnvZ was the only one of Y. pestis' 23 other 2CSs required for production of bubonic, septicemic and pneumonic plague. In vitro, OmpR-EnvZ was needed to counter serum complement and leukocytes but was not required for the secretion of antiphagocyte exotoxins. In vivo, Y. pestis lacking OmpR-EnvZ did not induce an early immune response in the skin and was fully virulent in neutropenic mice. We conclude that throughout the course of Y. pestis infection, OmpR-EnvZ is required to counter toxic effectors secreted by polymorphonuclear leukocytes in the tissues.
    The Journal of Infectious Diseases 05/2014; · 5.85 Impact Factor
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    ABSTRACT: One year after the occurrence of the first case of infection by the Middle East Respiratory Syndrome coronavirus (MERS-CoV) there is no clear consensus on the best treatment to propose. The World Health Organization, as well as several other national agencies, are still working on different clinical approaches to implement the most relevant treatment in MERS-CoV infection. We compared innate and adaptive immune responses of two patients infected with MERS-CoV to understand the underlying mechanisms involved in the response and propose potential therapeutic approaches. Broncho-alveolar lavage (BAL) of the first week and sera of the first month from the two patients were used in this study. Quantitative polymerase chain reaction (qRTPCR) was performed after extraction of RNA from BAL cells of MERS-CoV infected patients and control patients. BAL supernatants and sera were used to assess cytokines and chemokines secretion by enzyme-linked immunosorbent assay. The first patient died rapidly after 3 weeks in the intensive care unit, the second patient still recovers from infection. The patient with a poor outcome (patient 1), compared to patient 2, did not promote type-1 Interferon (IFN), and particularly IFNα, in response to double stranded RNA (dsRNA) from MERS-CoV. The absence of IFNα, known to promote antigen presentation in response to viruses, impairs the development of a robust antiviral adaptive Th-1 immune response. This response is mediated by IL-12 and IFNγ that decreases viral clearance; levels of both of these mediators were decreased in patient 1. Finally, we confirm previous in vitro findings that MERS-CoV can drive IL-17 production in humans. Host recognition of viral dsRNA determines outcome in the early stage of MERS-CoV infection. We highlight the critical role of IFNα in this initial stage to orchestrate a robust immune response and bring substantial arguments for the indication of early IFNα treatment during MERS-CoV infection.
    PLoS ONE 01/2014; 9(2):e88716. · 3.53 Impact Factor
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    ABSTRACT: Management of osteoarticular infections combines surgical treatment with antibiotic therapy. For some teams the immediate postoperative regimen requires at least partly wide-spectrum probabilistic treatment while waiting for the microbiological results. This protocol exposes the patient to the selection of resistant bacteria and the hospital unit to a modification of its bacterial ecology. The objective of this study was to retrospectively describe the microbial epidemiology of the Traumatology and Orthopaedics Department of the Lille University Hospital over 10 years (2002-2011). The bacterial species isolated in culture of osteoarticular samples were listed, after removing any duplicates. The antibiotics retained for follow-up were those used in treatment of these infections as well as those recognized as markers of resistance. For Gram-positive species, the antibiotics considered were methicillin, rifampicin, fluoroquinolones, glycopeptides, and linezolid; for the Gram-negative species, cefotaxime, cefepime, imipenem, and fluoroquinolones were considered. Of the 5006 strains isolated between 2002 and 2011, Gram-positive cocci accounted for more than 71%; Staphylococcus aureus 27%, and coagulase-negative staphylococci (CoNS) 54%. Contrary to S. aureus, resistance to methicillin, fluoroquinolones, and teicoplanin significantly increased in CoNS, reaching 44%, 34%, and 22%, respectively, of the strains in 2011. The proportion of streptococcal and enterococcal infections remained stable, a mean 7.4% and 5.3%, respectively, per year. Enterobacteria (12.5% of the isolates) were producers of extended-spectrum beta-lactamase in 7.8% of the cases. Pseudomonas aeruginosa was involved in 3.6% of the infections, and 12% of the strains remained resistant to ceftazidime. Propionibacterium acnes accounted for 5.8% of the bacteria isolated and showed few antibiotic resistance problems. Stability in the distribution and the susceptibility of different bacterial species was noted over this 10-year period. Although the evolution of S. aureus resistance was favourable, the resistance of CoNS specially to methicillin and glycopeptides increased. Level IV. Retrospective cohort study.
    Orthopaedics & Traumatology Surgery & Research 08/2013; · 1.06 Impact Factor
  • C. Loïez, M. Titécat, F. Wallet
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    ABSTRACT: Les méthodes de polymerase chain reaction (PCR) en temps réel peuvent détecter rapidement dans le sang des patients un large panel de micro-organismes. Elles présentent donc un intérêt dans la prise en charge des patients en permettant de documenter les états infectieux graves notamment en réanimation, ce d’autant que ces patients sont souvent sous antibiotiques au moment du prélèvement. Les kits commercialisés, dont le plus expertisé dans la littérature est le LightCycler® SeptiFast, fournissent 1,5 à 2 fois plus de résultats positifs comparés aux hémocultures. Cependant, si l’obtention de l’identification est rapide par ces kits couvrant 90 % des micro-organismes rencontrés en réanimation, peu de cibles renseignant sur la résistance aux antibiotiques sont disponibles. Or, compte tenu des résistances portées par ces microorganismes, la nécessité de rendre aux cliniciens un antibiogramme est primordiale et les techniques de bactériologie conventionnelles sont loin d’être obsolètes. Un résultat d’identification rapide positif pour une bactérie spécifique permettrait donc uniquement de décrémenter l’antibiothérapie afin de diminuer la pression de sélection. Ces techniques de PCR en temps réel doivent être interprétées en fonction du contexte clinique et il est important de s’interroger sur la signification d’un signal d’acide désoxyribonucléique (ADN) positif, sachant que celui-ci ne présage pas de la viabilité du microorganisme: quelle est la pertinence clinique d’une ADNémie bactérienne ou fongique ? Signifie-t-elle la présence d’un réel sepsis ? Peut-on au plan pronostique accorder un crédit à un signal positif alors que les hémocultures restent négatives ? C’est pourquoi un tel résultat doit toujours être interprété selon le tableau bioclinique du patient. Enfin, la rentabilité de ces tests de PCR en temps réel doit intégrer la notion de coût. C’est pourquoi ces techniques sont à réserver aux patients sévères en réanimation. De plus, le panel des pathogènes reconnus ainsi que les cibles de résistance aux antibiotiques devraient être plus larges pour que cette technologie puisse, à l’avenir, être utile à la prise en charge rapide du sepsis.
    Réanimation 05/2013; 22(3).
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    ABSTRACT: In case of periprosthetic joint infections, the antibiotic treatment administered intraoperatively entails consequences on bacterial ecology with potential secondary effects. This study evaluates the rapid detection of methicillin-resistant staphylococci (MRS) by Xpert® technology directly on intraoperative samples. Xpert® technology was compared to conventional culture for 104 clinical specimens performed on 30 patients. The performance of the test expressed in terms of sensitivity, specificity, positive predictive value, and negative predictive value was, respectively, 87.1%, 100%, 100%, and 94.5% for the 104 specimens, and 92.3%, 100%, 100%, and 94.4% for the 30 patients. With the rapid detection of MRS, the use of vancomycin was limited for 17 of these 30 patients. In conclusion, this technique would allow the implementation of first-line antibiotic treatment adapted to the presence of MRS or not within approximately 1 h and would strongly reduce the use of broad-spectrum antibiotics.
    Diagnostic microbiology and infectious disease 06/2012; 73(4):318-21. · 2.45 Impact Factor