Analysis Of Microbial Diversity And Main Pathogen Isolation And Drug Resistance

In this study, nineteen hoof swabs were collected from sheep with virulent footrot （VFR） inthe Hebei region of northern China. The19hoof swabs were randomly pooled into the sFR₁（n=6）, sFR₂（n=6）, and sFR₃（n=7） samples. Three healthy hoof swabs were collected fromone foot per footrot-unaffected animals in the diseased sheep herd, and pooled into the sFR-Csample, which served as a control for the comparisons of microbial diversity. Deep sequencingof bacterial16S rRNA genes was performed using the next-generation sequencing IlluminaMiSeq platform to compare the microbial diversity of the samples sFR₁, sFR₂and sFR₃from sheep with VFR to the sample sFR_C from healthy sheep from the same herd based on theV3-V4region of the16S rRNA gene. Moreover, the isolation, and drug resistance analysis of ofthe main pathogens were carried our. Results indicated that a total of246478trimmed sequencesof bacterial16S rRNA genes were obtained from the four pooled samples, generating308uniqueoperational taxonomic units. The composition analysis of the bacterial communities indicatedthat the sFR₁, sFR₂, and sFR₃samples were clearly different from sFR-C sample.Fusobacterium, Bacteroidetes, Firmicutes, and Proteobacteria were most prevalent phyla in thethree diseased samples, of which Fusobacterium necrophorum was the most highly prevalentspecies in all of the diseased samples. Bacteroides pyogenes was also highly prevalent in thesFR₂and sFR₃samples. Fusobacterium necrophorum was isolated from the disease-affectedsamples, and was identified by PCR method targeting the leukotoxin gene. The drug resistanceanalysis revealed that the Fusobacterium necrophorum isolate was highly sensitive for theantibiotics cefepime, kanamycin, gentamycin, polymyxin B, enrofloxacin and ciprofloxacin; andshowed drug resistance to the antibiotics penicillin, erythromycin, azithromycin, clindamycin,lincomycin, bacitracin, sulfisoxazole, and cotrimoxazole. Our findings of the microbial diversityof ovine VFR provide valuable information for further understanding of the ovine hoofmicrobiome and the etiology of footrot in sheep.