摘录
      众所周知，产气荚膜梭状芽孢杆菌毒素D型菌株会在绵羊、山羊和偶尔的牛中引起最常见的梭菌肠毒血症。1，2作为ABC-F家族的一员，optrA基因编码一种ATP结合盒蛋白，该蛋白通过保护细菌的核糖体，赋予对氯霉素和恶唑烷酮的耐药性。3近年来，据报道，恶唑烷酮/氯霉素耐药基因optrA在动物、人类和环境分离株中介导对氟苯尼考和利奈唑胺的高水平耐药性，对公众健康构成潜在威胁。据报道，4-6个Tn6218变体广泛存在于艰难梭菌分离株和偶尔的粪肠球菌分离株中；7，8然而，在产气荚膜梭菌中尚未报道可转移的Tn6218相关转座子。在此，我们鉴定了一株产气荚膜梭菌毒素D型菌株，命名为21-D-5，携带抗生素抗性基因optrA和Tn6218样转座子，并进一步分析了携带质粒p21-D-5b的Tn6218-样转座基因和optrA。
我们于2021年在陕西省渭南市采集了腹泻的关中奶山羊的直肠样本，并从样本中分离出一株产气荚膜梭菌21-D-5菌株。毒素基因检测表明21-D-5属于毒素型D，毒素基因plc、cpb2、etx和cpe阳性。采用肉汤微量稀释法检测21-D-5的抗生素耐药性和对克林霉素的强耐药性（MIC > 64 mg/L）、氟苯尼考（MIC > 64 mg/L）、氯霉素（MIC = 32 mg/L）和利奈唑胺（MIC = 16 mg/L）。然后用Nanopore PromethION平台（Biomarker Technologies，中国北京）进行21-D-5的WGS。WGS（NCBI生物样品：SAMN28005067）导致总长度为3 650 743 bp，其中两个质粒被命名为p21-D-5a（121 548 bp）和p21-D-5b（224 659 bp）进行检测。
Extract
Clostridium perfringens toxinotype D strains are known to cause the most common form of clostridial enterotoxaemia in sheep, goats and occasionally cattle.1,2 As a member of the ABC-F family, the optrA gene codes for an ATP-binding cassette protein that confers resistance to both phenicols and oxazolidinones by protecting the ribosomes of the bacteria.3 In recent years, the oxazolidinone/phenicol-resistant gene optrA has been reported to mediate high-level resistance to florfenicol and linezolid in isolates from animals, humans and the environment, posing a potential threat to public health.4–6 Tn6218 variants have been reported as widespread in Clostridioides difficile isolates and occasionally Enterococcus faecium isolates;7,8 however, the transferable Tn6218-related transposons has not yet been reported in C. perfringens. Herein, we identified one C. perfringens toxinotype D strain, designated as 21-D-5, harbouring antibiotic resistance gene optrA and Tn6218-like transposons, and further analysed the Tn6218-like transposons and optrA-carrying plasmid p21-D-5b.

We collected rectal samples from diarrhoeal Guanzhong diary goats in Weinan city, Shaanxi province in 2021, and one C. perfringens strain 21-D-5 was isolated from the samples. Toxin gene detection indicated 21-D-5 belonged to toxinotype D, positive for toxin genes plc, cpb2, etx and cpe. The broth microdilution method was used to examine the antibiotic resistance of 21-D-5, and strong resistance against clindamycin (MIC > 64 mg/L), florfenicol (MIC > 64 mg/L), chloramphenicol (MIC = 32 mg/L) and linezolid (MIC = 16 mg/L) was observed. WGS of 21-D-5 was then performed with the Nanopore PromethION platform (Biomarker Technologies, Beijing, China). WGS (NCBI BioSample: SAMN28005067) resulted in a total length of 3 650 743 bp, in which two plasmids designated as p21-D-5a (121 548 bp) and p21-D-5b (224 659 bp) were detected.

https://academic.oup.com/jac/article-abstract/78/1/311/6835810?login=false