School of Biomedical Sciences, The University of Western Australia, Western Australia, Australia; Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Thailand.
Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Thailand.
Anaerobe. 2020 Dec;66:102290. doi: 10.1016/j.anaerobe.2020.102290. Epub 2020 Oct 30.
Despite being incapable of causing Clostridium difficile infection, non-toxigenic C. difficile (NTCD) may still be relevant. This study explored the role of NTCD as a reservoir of accessory antimicrobial resistance (AMR) genes in NTCD from Southeast Asia. This region has high rates of antimicrobial use, a high prevalence of NTCD and phenotypic AMR in such strains. More than half of the 28 NTCD strains investigated had at least one accessory AMR gene on mobile genetic elements (MGEs) which were similar to the elements found in other bacteria, including Erysipelothrix rhusiopathiae and Streptococcus suis, both of which are found in the pig gut. Thus, C. difficile may facilitate the movement of AMR genes between different hosts within a wide range of pathogenic bacteria. C. difficile β-lactamases were not located on MGEs and were unlikely to be transferred. Concordance between the MLS resistance genotype and phenotype was low, suggesting multiple resistance mechanisms, many of which remain unknown. On the contrary, there was a high concordance between resistance genotype and phenotype for both fluoroquinolones and rifaximin. From an epidemiological perspective, NTCD populations in Southeast Asia comprised members of evolutionary clades 1 and 4, which are thought to have originated from Europe and Asia, respectively. This population structure reflects the close relationship between the people of the two regions.
尽管无毒性艰难梭菌（NTCD）不能引起艰难梭菌感染，但它可能仍然具有相关性。本研究探讨了 NTCD 作为辅助抗菌药物耐药（AMR）基因库在东南亚 NTCD 中的作用。该地区的抗生素使用率很高，NTCD 流行率高，且此类菌株表现出表型 AMR。在所研究的 28 株 NTCD 菌株中，超过一半的菌株至少有一种辅助 AMR 基因位于移动遗传元件（MGE）上，这些基因与其他细菌（包括猪肠道中的猪红斑丹毒丝菌和猪链球菌）中的基因相似。因此，艰难梭菌可能促进了 AMR 基因在不同宿主之间的广泛传播。艰难梭菌β-内酰胺酶并未位于 MGE 上，不太可能发生转移。MLS 耐药基因型与表型之间的一致性较低，表明存在多种耐药机制，其中许多仍未知。相反，氟喹诺酮类药物和利福昔明的耐药基因型与表型之间具有很高的一致性。从流行病学角度来看，东南亚的 NTCD 群体由进化枝 1 和 4 的成员组成，据推测它们分别起源于欧洲和亚洲。这种群体结构反映了这两个地区人民之间的密切关系。
