Incidence and characterization of Clostridium perfringens isolated from antibiotic-associated diarrhoeal patients: a prospective study in an Indian hospital

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, molecular characterization, and antimicrobial resistance profile of Clostridium perfringens from India: A scoping review

Clostridium perfringens is one of the most important foodborne pathogens that causes histotoxic diseases and intestinal infections in both humans and animals. The present scoping review has been designed to analyze the literature published during 2000-2021 from India on the prevalence, molecular characterization, and antimicrobial resistance profile of C. perfringens isolates recovered from humans, animals, animal-based foods, and associated environmental samples. The peer-reviewed articles retrieved from four electronic databases (Google Scholar, PubMed, Science Direct, and Web of Science) were assessed using PRISMA-ScR guidelines. A total of 32 studies from India were selected on the basis of their relevance and inclusion criteria. The overall prevalence of C. perfringens among domestic animals having history of clinical symptoms and among healthy animals was found to be 65.8% (508/772) and 42.8% (493/1152), respectively. The pathogen was also detected in clinically affected wild animals (75%), healthy wild animals (35.4%), and captive birds (24.5%). The detection of C. perfringens among poultry having necrotic enteritis and among healthy birds was found to be 66.8% (321/480) and 25.6% (80/312), respectively. The detection of pathogen among animal-based foods (i.e., meat, milk, and fish and their products) and environmental samples depicted a prevalence of 20.8% (325/1562) and 30.2% (23/76), respectively. However, the prevalence of C. perfringens among humans having history of diarrhea and among healthy humans was found to be 25% (70/280) and 23.2% (36/155), respectively. The genotyping of C. perfringens isolates revealed that toxin type A was found to be the most prevalent genotype. Along with the alpha toxin gene (cpa), beta (cpb), epsilon (etx), iota (itx), enterotoxin (cpe), beta-2 toxin (cpb2), and NetB (netB) toxins were also detected in different combinations. Antimicrobial resistance profile of C. perfringens isolates recovered from different sources demonstrated that the highest resistance was detected against sulphonamides (76.8%) and tetracycline (41.3%) by phenotypic and genotypic detection methods, respectively. Comprehensive scientific studies covering different geographical areas at the human-animal-environment interface are crucial to generalize the real magnitude of C. perfringens-associated problem in India and for establishing a reliable database.

A novel in situ methodology for visual detection of Clostridium perfringens in pork harnessing saltatory rolling circle amplification

Clostridium perfringens (C. perfringens), a prolific toxin-producing anaerobe is an important foodborne pathogen with a huge public health concern. Rapid and on-site detection of C. perfringens is of specific importance in developing countries. In the present study, saltatory rolling circle amplification (SRCA) assay was developed for culture-independent, rapid and visual detection of C. perfringens and evaluated in meat with pork as a model. The specificity of the SRCA assay was ascertained by using 62 C. perfringens and 18 non- C. perfringens strains. The analytical sensitivity of the developed SRCA, conventional and real-time PCR assays were 80 fg, 800 fg and 800 fg DNA per tube, respectively. The limit of detection of the SRCA assay was 80 CFU/g of pork in the absence of enrichment and 8 CFU/g after short enrichment of 6 h. The detection limits of 80 CFU/g and 8 CFU/g of pork were attained within 120 min and 8 h, respectively. Real-world or field relevancy of the developed assay was evaluated by screening 82 raw and processed pork samples. As the developed assay is simple, user-friendly, cost-effective and sophisticated-equipment free, it would be more suitable for on-site testing of C. perfringens in foods. To our information, this is the first report to apply SRCA for the detection of C. perfringens.

Development of a novel polymerase spiral reaction (PSR) assay for rapid and visual detection of Clostridium perfringens in meat

C. perfringens is a widespread foodborne pathogen and one of the major concerns in the meat industry. There is a need for a simple, rapid and equipment free detection system for C. perfringens as conventional anaerobic culture method is labour and resource intensive. Here, we applied a novel polymerase spiral reaction phenomenon to develop and evaluate an assay for effortless and visual detection of C. perfringens in meat foods employing pork as a representative model. Specificity of the assay was determined using 51 C perfringens and 20 non- C. perfringens strains. Analytical sensitivity of the developed test was 80 fg DNA per tube indicating 100 times more sensitivity than end-point PCR assay. The detection limits were 980 CFU/g and 9.8 × 10⁴ CFU/g of pork for PSR and PCR assays, respectively. The operation time of the PSR assay including DNA extraction was 120 min. The developed PSR assay was accurate and effective in comparison to culture method, in detecting C. perfringens in 38 of 74 pork samples. Therefore the specificity, sensitivity, negative predictive value, positive predictive value and accuracy rate of the developed PSR assay were 100%. The developed PSR assay is easy to perform, rapid, affordable, permitting sophisticated-equipment free amplification and naked eye interpretation. This is the initial report in which the PSR assay was optimized for the detection of C. perfringens.

Prevalence and characterization of Clostridium perfringens toxinotypes among patients with antibiotic-associated diarrhea in Iran

Clostridium perfringens has emerged as an important cause of antibiotic-associated diarrhea (AAD), particularly in the hospital environment. Here we investigated the prevalence and molecular epidemiology of C. perfringens isolated from 2280 fecal samples from Iranian diarrheal patients suspected of having AAD. Overall, AAD was diagnosed in 13.3% (303/2280) of patients and associated with advanced age (>50 years, P = 0.001). A total of 106 C. perfringens isolates were cultured from AAD (n = 68) and non-AAD (n = 38) groups, with toxinotypes A and F comprising 84% and 16% of isolates, respectively. Notably, 41.2% of type F strains were also cpb2-positive and enterotoxigenic cpe-positive strains were detected in 13.2% of the isolates from AAD patients. Genes associated with the VirR/VirS signal transduction (virR, virS) and accessory gene regulator (agrB, agrD) systems were detected in 56.6% and 67% of the isolates, respectively, and peptides of the quorum-sensing modulator, AgrD were highly conserved across all strains. The high prevalence of C. perfringens in Iranian AAD patients suggests that diagnostic laboratories in this region should consider screening for C. perfringens in cases of suspected AAD, especially if the specimen is negative for other pathogens and/or the patients are aged >50 years.

Distribution of Clostridium perfringens isolates from piglets in South Korea

Clostridium perfringens causes various digestive system disease symptoms in pigs. In the present study, 11 C. perfringens isolates were obtained from diarrheic piglets and 18 from healthy piglets. All of the C. perfringens isolates were shown to be type A using a multiplex PCR assay. The β2 toxin gene was detected in 27/29 C. perfringens isolates, i.e., 81% (9/11) of diarrheic piglets and 100% (18/18) of healthy piglets, and all of the genes had the same sequence. In conclusion, the β2 toxin gene of C. perfringens was distributed widely in Korean piglets regardless of the incidence of diarrhea, and there was no clear relationship with enteric disease. A pulsed-field gel electrophoresis analysis of DNA digested using SmaI demonstrated the non-clonal spread of C. perfringens isolates from piglets.