title: Antibiotics involved in Clostridium difficile-associated disease increase colonization factor gene expression.
abstract: 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 genes encoding known, or putative, colonization factors: three adhesins, P47 (one of the two S-layer proteins), Cwp66 and Fbp68, and a protease, Cwp84. The conditions studied included hyperosmolarity, iron depletion and exposure to several antibiotics (ampicillin, clindamycin, ofloxacin, moxifloxacin and kanamycin). The analysis was performed on three toxigenic and three non-toxigenic C. difficile isolates using real-time PCR. To complete this work, the impact of ampicillin and clindamycin on the adherence of C. difficile to Caco-2/TC7 cells was analysed. Overall, for the six strains of C. difficile studied, exposure to subinhibitory concentrations (1/2 MIC) of clindamycin and ampicillin led to the increased expression of genes encoding colonization factors. This was correlated with the increased adherence of C. difficile to cultured cells under the same conditions. The levels of gene regulation observed among the six strains studied were highly variable, cwp84 being the most upregulated. In contrast, the expression of these genes was weakly, or not significantly, modified in the presence of ofloxacin, moxifloxacin or kanamycin. These results suggest that, in addition to the disruption of the normal intestinal microbiota and its barrier effect, the high propensity of antibiotics such as ampicillin and clindamycin to induce C. difficile infection could also be explained by their direct role in enhancing colonization by C. difficile.
authors.affiliation: Université Paris Sud-XI, USC INRA 4043, Faculté de Pharmacie, Châtenay-Malabry, France.
authors.forename: Cécile
authors.initials: C
authors.lastname: Denève
authors.affiliation: Université Paris Sud-XI, IFR 141, Faculté de Pharmacie, Châtenay-Malabry, France.
authors.forename: Claudine
authors.initials: C
authors.lastname: Deloménie
authors.affiliation: Université Paris Sud-XI, USC INRA 4043, Faculté de Pharmacie, Châtenay-Malabry, France.
authors.forename: Marie-Claude
authors.initials: MC
authors.lastname: Barc
authors.affiliation: AP-HP, Laboratoire de Microbiologie, Hôpital Jean Verdier, Bondy, France.|Université Paris Sud-XI, USC INRA 4043, Faculté de Pharmacie, Châtenay-Malabry, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Collignon
authors.affiliation: Université Paris Sud-XI, USC INRA 4043, Faculté de Pharmacie, Châtenay-Malabry, France.
authors.forename: Claire
authors.initials: C
authors.lastname: Janoir
mesh_terms: D018829:Adhesins, Bacterial / Q000187:drug effects / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000009:adverse effects* / Q000494:pharmacology; D001422:Bacterial Adhesion / Q000187:drug effects / Q000502:physiology; D001426:Bacterial Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D016360:Clostridioides difficile / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D003015:Clostridium Infections / Q000382:microbiology*; D003967:Diarrhea / Q000139:chemically induced* / Q000382:microbiology; D004351:Drug Resistance; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D007501:Iron / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D009994:Osmolar Concentration
chemical_list: D018829:Adhesins, Bacterial; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D007501:Iron