Prevalence of Clostridium perfringens toxinotypes in antibiotic-associated diarrheal (AAD) patients in Iranian hospitals; can toxinotype D serve as a possible zoonotic agent for humans?

While Clostridium perfringens (C. perfringens) toxinotype F is known as the cause of 15% of antibiotic-associated diarrhea (AAD) and sporadic diarrhea (SD) cases, the association of the other C. perfringens toxinotypes with AAD/SD is not investigated. Therefore, the incidence of C. perfringens-associated diarrhea was investigated in hospitalized patients in six Iranian hospitals. A total of 151 stool specimens from AAD/SD patients were investigated for C. perfringens strains and the isolates were analyzed for the major (cpa, cpb, etx, and iap) and minor (cpe, cpb2, netb, PFO, and tpeL) toxin genes by PCR. C. perfringens isolation ratio was 28.5% (43 of 151 patients). C. perfringens isolation rates were not significant between different gender and age groups (p > 0.05), whereas it was significant between different wards and hospitals (p < 0.01). The cpa gene was detected in all C. perfringens isolates (n = 116). After that, the highest prevalence belonged to tpeL (87.1%), followed by pfo (84.5%), cpb2 (69.8%), cpe (55.2%), etx (12.9%), and netb (1.7%) genes. Based on these gene profiles, 35 (30.2%), 64 (55.2%), 15 (12.9%), and two (1.7%) isolates belonged to toxinotypes A, F, D, and G, respectively, and the other toxinotypes were not detected. This study persists in considering toxinotype F in Iranian AAD patients as it was the dominant C. perfringens toxinotype. Remarkably, the isolation of toxinotype D suggests it as a potential trigger in C. perfringens-associated AAD for the first time and highlights it as a possible zoonotic agent for humans.

Prevalence, characteristics and antimicrobial susceptibility patterns of Clostridioides difficile isolated from hospitals in Iran.

OBJECTIVES: Clostridioides (previously Clostridium) difficile is a major growing cause of nosocomial diarrhoea known as C. difficile infection (CDI). This study investigated the prevalence and antimicrobial resistance patterns of C. difficile isolated from patients suffering from diarrhoea in Iran between 2016-2018. METHODS: A total of 151 stool specimens were collected and were screened for the presence of C. difficile. Specimens were examined for toxins by culture, enzyme immunoassay (EIA) and PCR. Antimicrobial susceptibility testing was performed for 12 antibiotics (metronidazole, vancomycin, clindamycin, tetracycline, erythromycin, ciprofloxacin, levofloxacin, moxifloxacin, fusidic acid, piperacillin, piperacillin/tazobactam and rifampicin) by the disk diffusion method according to the guidelines of the CLSI, EUCAST and CA-SFM. RESULTS: Of 151 stool specimens, 66 (43.7%) were positive for C. difficile by PCR, whereas 2 (1.3%) were only positive for C. difficile toxins based on EIA. A total of 292 clostridial isolates were obtained from specimens by culture, of which 133 (45.5%) were finally confirmed as C. difficile by PCR. Of 121 isolates resistant to at least one antibiotic, 107 (88.4%) were resistant to three or more antimicrobials and thus were defined as multidrug-resistant (MDR). Different and diverse resistance patterns to the antimicrobial drugs were seen among the isolates. CONCLUSION: This is the first report of the isolation of C. difficile from different governmental hospitals of Iran and indicates that CDI might be an important nosocomial infection in different hospital wards. Moreover, this study provides a comprehensive picture of the MDR phenotype characteristics of C. difficile isolates in Iran.