We (i) determined the prevalence ofClostridium difficileand their antimicrobial resistance to six antimicrobial classes, in a variety of fresh vegetables sold in retail in Ohio, USA, and (ii) conducted cumulative meta-analysis of reported prevalence in vegetables since the 1990s. Six antimicrobial classes were tested for their relevance as risk factors forC. difficileinfections (CDIs) (clindamycin, moxifloxacin) or their clinical priority as exhaustive therapeutic options (metronidazole, vancomycin, linezolid, and tigecycline). By using an enrichment protocol we isolatedC. difficilefrom three of 125 vegetable products (2.4%). All isolates were toxigenic, and originated from 4.6% of 65 vegetables cultivated above the ground (n=3; outer leaves of iceberg lettuce, green pepper, and eggplant). Root vegetables yielded noC. difficile. TheC. difficileisolates belonged to two PCR ribotypes, one with an unusual antimicrobial resistance for moxifloxacin and clindamycin (lettuce and pepper; 027-like, A+B+CDT+;tcdC18 bp deletion); the other PCR ribotype (eggplant, A+B+CDT−; classictcdC) was susceptible to all antimicrobials. Results of the cumulative weighted meta-analysis (6 studies) indicate that the prevalence ofC. difficilein vegetables is 2.1% and homogeneous(P<0.001)since the first report in 1996 (2.4%). The present study is the first report of the isolation ofC. difficilefrom retail vegetables in the USA. Of public health relevance, antimicrobial resistance to moxifloxacin/clindamycin (a bacterial-associated risk factor for severe CDIs) was identified on the surface of vegetables that are consumed raw.
First report of antimicrobial resistance pre-dates penicillin
