Molecular characterization of Clostridium perfringens isolated from cattle and sheep carcasses and its antibiotic resistance patterns in Shiraz slaughterhouse, southern Iran

Clostridium perfringens type A food-borne poisoning is often caused by C. perfringens enterotoxin (CPE) encoded by chromosomal cpe. Contamination of meat with C. perfringens usually leads to food poisoning outbreaks. To find more information regarding the causative agent, we focused on the identification of type A containing cpe and netB genes in cattle and sheep carcasses slaughtered at Shiraz slaughterhouse and investigated the prevalence of antibiotic-resistant plasmid in isolated C. perfringens. 200 specimens were randomly collected by swabbing the whole outer and inner surface of the carcasses, and processed for selective culture on sulfadiazine polymyxin sulphate agar (SPS). The suspected colonies were further identified using species-specific primers as to confirm the presence of the cpa, cpe, netB and tetracycline and enrofloxacin gene resistance patterns. Our results demonstrated that out of 90 and 70 colonies of the positive cultures from cattle and sheep samples, respectively, 40% and 35.7% of the suspected colonies were identified as C. perfringens type A by PCR assay. Moreover, from those type A isolates, only 1 (2.7%) isolate was positive for both cpe and netB genes in the cattle carcasses. The MIC values also showed high tetracycline resistance patterns for cattle (45.8%) and sheep (92.3%) while all of the PCR positive C. perfringens type A isolates were susceptible to enrofloxacin. The high prevalence of C. perfringens in slaughtered animals with a high rate of resistance to tetracycline implies the need for caution in the use of antibiotic in food animals.