Detection of antibiotic resistance toxigenic Clostridium difficile in processed retail lettuce

Abstract

Abstract Objectives: Clostridium difficile is the major cause of infectious diarrhoea in humans after antimicrobial treatment. Clostridium difficile has been isolated from food animals and meat. The main purpose of this study was to characterize C. difficile isolated from retail lettuce and determine the antibiotic resistance using five common clinical-selected antibiotics (metronidazole, vancomycin, clindamycin, erythromycin, and cefotaxime). Materials and Methods: Lettuce samples (grown in California, Arkansas, and Louisiana) were purchased from retail stores. Results: Toxigenic C. difficile was isolated from 13.8 per cent (41/297) of the lettuce samples. Among the toxigenic isolates, only 82.9 per cent (34/41) produced toxin B, 17.1 per cent (7/41) produced both toxin A and toxin B, and two of the Louisiana C. difficile isolates were identified as ribotype 027. Under the treatment of the five antibiotics, the virulence C. difficile isolates were identified as having antibiotic resistance to metronidazole, vancomycin, and erythromycin. Conclusion: The present study reports the highest prevalence of toxigenic C. difficile in US retail lettuce. The antibiotic resistance to metronidazole, vancomycin, and erythromycin of the isolated C. difficile from retail lettuces could lead to public health concerns.