National Risk Assessment laboratory for antimicrobial resistance of animal original bacteria, College of Veterinary Medicine, South China Agricultural University (SCAU), Guangzhou, China.
Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University (SCAU), Guangzhou, China.
PLoS One. 2019 Feb 26;14(2):e0212965. doi: 10.1371/journal.pone.0212965. eCollection 2019.
We investigated the molecular characteristics and antimicrobial susceptibility of Clostridium difficile isolated from animals in China. We obtained 538 rectal swabs from pigs, chickens and ducks in 5 provinces during 2015 and 2016. C. difficile isolates were characterized by detection of toxin genes, multilocus sequence typing and ribotyping. And antimicrobial susceptibility testing was performed using the agar dilution method. Out of 538 samples, 44 (8.2%) were C. difficile positive with high prevalence in pigs (n = 31). Among these, 39 (88.6%) were toxigenic including 14 (31.8%) that were A+B+CDT+ and 13 (29.5%) A+B+. The remaining 12 (27.3%) were A-B+. We identified 7 ST types and 6 PCR ribotypes. The most predominant type was ST11/RT078 with toxin profile A+B+CDT+ and all were isolated from piglets with diarrhea. ST109 isolates possessed two different toxigenic profiles (A-B-CDT- and A-B+CDT-) and although it was not the most prevalent sequence type, but it was widely distributed between chickens, ducks and pigs in the 5 provinces. All C. difficile isolates were fully susceptible to vancomycin, metronidazole, fidaxomicin, amoxicillin/clavulanate and meropenem but retained resistance to 4 or 5 of the remaining antibiotics, especially cefotaxime, tetracycline, ciprofloxacin, cefoxitin. The RT078/ST11 isolates were simultaneously resistant to cefotaxime, tetracycline, cefoxitin, ciprofloxacin and imipenem. This is the first report of the molecular epidemiology of C. difficile isolated from food animals in China. We identified the epidemic strain RT078/ST11 as the predominate isolate among the animals we screened in our study.
我们研究了来自中国动物的艰难梭菌的分子特征和抗菌药物敏感性。我们于 2015 年和 2016 年在 5 个省的 538 份猪、鸡和鸭的直肠拭子中获得了艰难梭菌分离株。通过毒素基因检测、多位点序列分型和核糖体分型对艰难梭菌分离株进行了特征描述，并采用琼脂稀释法进行了抗菌药物敏感性试验。在 538 个样本中，有 44 个（8.2%）为艰难梭菌阳性，其中猪的阳性率最高（n=31）。其中 39 个（88.6%）为产毒株，包括 14 个（31.8%）A+B+CDT+和 13 个（29.5%）A+B+。其余 12 个（27.3%）为 A-B+。我们鉴定了 7 种 ST 型和 6 种 PCR 核糖体型。最主要的类型是 ST11/RT078，其毒素谱为 A+B+CDT+，均分离自仔猪腹泻。ST109 分离株具有两种不同的产毒谱（A-B-CDT-和 A-B+CDT-），尽管它不是最常见的序列类型，但在 5 个省的鸡、鸭和猪中广泛分布。所有艰难梭菌分离株对万古霉素、甲硝唑、非达霉素、阿莫西林/克拉维酸和美罗培南完全敏感，但保留了对 4 种或 5 种剩余抗生素的耐药性，尤其是头孢噻肟、四环素、环丙沙星、头孢西丁。RT078/ST11 分离株同时对头孢噻肟、四环素、头孢西丁、环丙沙星和亚胺培南耐药。这是中国首次报告从食用动物中分离出的艰难梭菌的分子流行病学情况。我们发现流行株 RT078/ST11 是我们研究中筛选的动物中的主要分离株。
