Identification of a novel zinc metalloprotease through a global analysis of clostridium difficile extracellular proteins

Clostridium difficile is a major cause of infectious diarrhea worldwide. Although the cell surface proteins are recognized to be important in clostridial pathogenesis, biological functions of only a few are known. Also, apart from the toxins, proteins exported by C. difficile into the extracellular milieu have been poorly studied. In order to identify novel extracellular factors of C. difficile, we analyzed bacterial culture supernatants prepared from clinical isolates, 630 and R20291, using liquid chromatography-tandem mass spectrometry. The majority of the proteins identified were non-canonical extracellular proteins. These could be largely classified into proteins associated to the cell wall (including CWPs and extracellular hydrolases), transporters and flagellar proteins. Seven unknown hypothetical proteins were also identified. One of these proteins, CD630_28300, shared sequence similarity with the anthrax lethal factor, a known zinc metallopeptidase. We demonstrated that CD630_28300 (named Zmp1) binds zinc and is able to cleave fibronectin and fibrinogen in vitro in a zinc-dependent manner. Using site-directed mutagenesis, we identified residues important in zinc binding and enzymatic activity. Furthermore, we demonstrated that Zmp1 destabilizes the fibronectin network produced by human fibroblasts. Thus, by analyzing the exoproteome of C. difficile, we identified a novel extracellular metalloprotease that may be important in key steps of clostridial pathogenesis

Carriage of ESBL-producing Enterobacteriaceae in French hospitals: the PORTABLSE study

International audienc

Comparative In Vitro Activities of Caspofungin and Micafungin, Determined Using the Method of the European Committee on Antimicrobial Susceptibility Testing, against Yeast Isolates Obtained in France in 2005-2006▿

The in vitro activities of caspofungin and micafungin against 1,038 yeast isolates have been determined. The caspofungin and micafungin MICs were lower for Candida albicans, Candida glabrata, and Candida tropicalis than for Candida parapsilosis, Candida guilliermondii, and Candida krusei. A clear correlation was seen between the MICs for the two drugs

One-day prevalence of asymptomatic carriage of toxigenic and non-toxigenic Clostridioides difficile in 10 French hospitals

International audienceBackground: Asymptomatic faecal carriage of Clostridioides difficile has been widely evaluated, but its prevalence across a wide range of clinical departments and related risk factors are not well described. The objectives of the PORTADIFF study were to evaluate the prevalence and identifying risk factors leading to asymptomatic carriage of both toxigenic and non-toxigenic C. difficile.Methods: The PORTADIFF study was a 1-day prevalence study carried out in 10 different French hospitals. Adult patients, who agreed to participate, were included in this study and provided a fresh stool sample. C. difficile strains isolated from carriage were characterized by polymerase chain reaction (PCR) detection of tcdA, tcdB, cdtA and cdtB, and PCR ribotyping.Results: In total, 721 patients were included in this study. The median age was 73 years (range 18-101 years) and the male/female ratio was 1.06. C. difficile (either toxigenic or non-toxigenic strains) was isolated from 79 (11%) patients; 42 (5.8%) strains were toxigenic. The prevalence rates of asymptomatic carriage ranged from 5% on surgical wards to 19% on long-term care wards. The main risk factors associated with asymptomatic carriage were antibiotic treatment within the preceding 3 months (81.8% vs 53.7%; P<0.01), hospitalization within the preceding 2 months (55.8% vs 33%; P<0.01), cumulative duration of hospital stay before study inclusion (mean 50.1 vs 34.5 days; P<0.047), and hospitalization on a ward with high global incidence of C. difficile infection.Conclusion: Eleven percent of hospitalized patients were asymptomatic carriers of toxigenic or non-toxigenic C. difficile, and may constitute a potential reservoir of C. difficile strains