Prevalence, antibiogram, phenotypic and genotypic analysis of Clostridioides difficile toxigenic strains from stool samples

Abstract

Clostridioides difficile (C. difficile) is a Gram-positive, spore-forming, toxin-producing, anaerobic bacterium that is a prominent cause of nosocomial antibiotic-associated diarrhea. Toxin-mediated C. difficile infections can cause a variety of diseases, from minor cases of diarrhea to life-threatening pseudomembranous colitis in mammals. This study aimed to detect C. difficile in patients admitted to King Saud Medical City (KSMC), to determine the phenotypic and genotypic types of the toxigenic C. difficile isolates, and to investigate the antimicrobial susceptibility patterns of these isolates. The study was conducted from January 2021 to December 2021 and involved 313 stool samples obtained from patients at KSMC and tested for the presence of C. difficile. Anaerobic incubation of each stool sample was carried out using C. difficile selective agar at 37 ± 2⁰C for 48–72 h to enable phenotypic characterization. For phenotypic detection and toxigenic isolate differentiation, a commercial kit, ImmunoCard Toxins A & B, was used. The E test and Brucella modified blood agar were used to determine antimicrobial susceptibility. Real-time polymerase chain reactions using GeneXpert were performed to detect the genotypes of toxigenic strains. Antimicrobial susceptibility testing revealed that all isolates were sensitive to vancomycin and metronidazole, while 89.3% and 82.1% were sensitive to moxifloxacin and tetracycline, respectively. Furthermore, the prevalence of toxigenic CDI was 9.3%.

Keywords

• Clostridioides difficile
• Toxigenic C. difficile
• Antibiogram
• CDI
• Riyadh