Department of Veterinary and Animal Sciences, University of Copenhagen, Frederiksberg C, Denmark.
Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Artillerivej 5, 2300, Copenhagen, Denmark.
Anaerobe. 2021 Feb;67:102317. doi: 10.1016/j.anaerobe.2020.102317. Epub 2021 Jan 6.
There is an increasing concern about the role of animals as reservoirs of Clostridioides difficile. In this study, we investigated prevalence, antimicrobial resistance and zoonotic potential of C. difficile in dogs. Two-hundred and twenty-five dog faecal deposits were collected from trashcans in nine public gardens. C. difficile was isolated using selective plating and enrichment culture, identified by MALDI-TOF, tested for susceptibility to seven antibiotics by E-test, and sequenced on an Illumina NextSeq platform. Genome sequences were analysed to determine multilocus sequence types and resistance and toxin gene profiles. Zoonotic potential was assessed by measuring genetic variations of core genome (cg)MLST types between canine isolates and 216 temporally and spatially related human clinical isolates from a national database. C. difficile was isolated from 11 samples (4.9%). Seven isolates were toxigenic (tcdA+, tcdB+, cdtA/B-) and belonged to the sequence types ST2, ST6, ST10 and ST42. The four non-toxigenic isolates were assigned to ST15, ST26 and one novel ST. ST2, corresponding to PCR ribotype RT014/020, was the dominating lineage (n = 4) and, together with ST26 and ST42 isolates, showed close resemblance to human isolates, i.e. 2-5 allelic differences among the 1999 genes analysed by cgMLST. Three non-toxigenic isolates displayed resistance to clindamycin, erythromycin and tetracycline mediated by erm(B) and tet(M). Resistance to metronidazole, moxifloxacine, rifampicin or vancomycin was not detected. In conclusion, a small proportion of faecal deposits contained toxigenic C. difficile such as ST2 (RT014/020), which is a major cause of community-acquired infections. Our finding suggests that pathogenic strains can be exchanged between dogs and humans.
人们越来越关注动物作为艰难梭菌（Clostridioides difficile）储主的作用。在这项研究中，我们调查了狗中艰难梭菌的流行率、抗生素耐药性和人畜共患潜力。从九个公共花园的垃圾桶中收集了 225 份狗粪便沉积物。使用选择性平板和富集培养分离艰难梭菌，通过 MALDI-TOF 鉴定，通过 E 试验测试对七种抗生素的敏感性，并用 Illumina NextSeq 平台测序。对基因组序列进行分析，以确定多位序列型和耐药性及毒素基因谱。通过测量核心基因组（cg）MLST 型之间的遗传变异，评估人畜共患病的潜力，从国家数据库中，来自 216 个时间和空间相关的人类临床分离株和 11 个犬分离株。从 11 个样本（4.9%）中分离出艰难梭菌。7 个分离株为产毒株（tcdA+，tcdB+，cdtA/B-），属于序列型 ST2、ST6、ST10 和 ST42。4 个非产毒株被分配到 ST15、ST26 和一个新的 ST。ST2，对应于 PCR 核糖体型 RT014/020，是主要的谱系（n=4），与 ST26 和 ST42 分离株一起，与人分离株非常相似，即 1999 个基因中 2-5 个等位基因差异通过 cgMLST 分析。3 个非产毒株对克林霉素、红霉素和四环素表现出耐药性，由 erm（B）和 tet（M）介导。未检测到对甲硝唑、莫西沙星、利福平或万古霉素的耐药性。总之，一小部分粪便沉积物中含有产毒艰难梭菌，如 ST2（RT014/020），这是社区获得性感染的主要原因。我们的发现表明，致病性菌株可以在狗和人之间交换。
