Prevalence, toxin-typing and antimicrobial susceptibility of Clostridium perfringens in sheep with different feeding modes from Gansu and Qinghai provinces, China

The purpose of this study was to determine the prevalence and antimicrobial resistance of Clostridium perfringens from sheep (intensive husbandry) in Gansu and Tibetan sheep (extensive husbandry) in Qinghai, China.400 fecal samples (sheep, n = 320, Tibetan sheep, n = 80) were collected from Gansu and Qinghai for C. perfringens isolation. Toxin genes were detected by PCR, antimicrobial susceptibility testing was carried out by broth microdilution method, and whole genome was sequenced using Illumina HiSeq.83 strains of C. perfringens (sheep, n = 47; Tibetan sheep, n = 36) were isolated from the samples. 44.5% (37/83) of the isolates were positive for cpb2, while 34.9% (29/83) of the isolates were positive for cna. 95.2% isolates were resistant to sulfonamides, followed by tetracycline (22.9%), ampicillin (14.5%), penicillin (10.8%), doxycycline (4.8%), and amoxicillin (1.2%). The isolates from same source shared similar allelic profile and closer genetic relationship. A total of 14 toxin genes and 11 antimicrobial resistance genes were detected among the sequenced isolates, and 10 sequenced C. perfringens isolates carried multiple (n ≥ 3) antimicrobial-resistance genes. Moreover, oxazolidinone-resistant gene optrA was detected in one isolate from Tibetan sheep, which co-harbored tetA(P), aac(6')-aph(2″), ant(6)-Ib, erm(Q), fexA, tet(44), erm(A) and erm(B).C. perfringens from sheep and Tibetan sheep shared different prevalence rates and antimicrobial-resistance, and the isolates from same source shared closer genetic relationship.