School of Biomedical Sciences, Faculty of Health and Medical Sciences, The University of Western Australia, Queen Elizabeth II Medical Centre, Nedlands, 6009, Western Australia, Australia.
Medical, Molecular and Forensic Sciences, College of Science, Health, Engineering and Education, Murdoch University, Murdoch, 6105, Western Australia, Australia.
Anaerobe. 2019 Dec;60:102066. doi: 10.1016/j.anaerobe.2019.06.019. Epub 2019 Jun 28.
The global emergence of epidemic Clostridium difficile PCR ribotype (RT) 027 prompted enhanced surveillance of emerging strains. Recently, there have been reports of severe C. difficile infection in Australia caused by an unusual strain of C. difficile not seen previously. Identified as PCR RT251, this strain produces toxins A (TcdA) and B (TcdB), as well as binary toxin (CDT), and shares a common phylogenetic lineage with RT027. In this study, C. difficile RT251 strains were sourced from various geographical locations and potential virulence factors were evaluated and compared to that of control strains, CD630, VPI10463 and R20291 invitro. C. difficile RT251 strains were motile, germinated and sporulated efficiently, despite producing significantly less TcdA and TcdB compared to all control strains. Genomic analyses revealed three multi-locus sequence types (MLSTs 188, 231 and 365) with four to five loci variants compared to RT027 (ST1) all MLST clade 2. C. difficile RT251 strains were susceptible to metronidazole, vancomycin and moxifloxacin, a fluoroquinolone antimicrobial to which RT027 strains are often resistant. Further studies using whole-genome sequencing are required to determine additional virulence factors that may contribute to the pathogenicity of C. difficile RT251 strains.
全球流行的艰难梭菌 PCR 核糖型 (RT) 027 促使加强了对新菌株的监测。最近，澳大利亚有报道称，一种以前从未见过的不寻常艰难梭菌菌株引起了严重的艰难梭菌感染。这种菌株被鉴定为 PCR RT251，它产生毒素 A (TcdA) 和 B (TcdB)，以及二元毒素 (CDT)，并与 RT027 具有共同的系统发育谱系。在这项研究中，艰难梭菌 RT251 菌株来自不同的地理位置，评估了潜在的毒力因子，并与对照菌株 CD630、VPI10463 和 R20291 在体外进行了比较。艰难梭菌 RT251 菌株具有运动性，能够有效地发芽和形成孢子，尽管与所有对照菌株相比，TcdA 和 TcdB 的产量明显减少。基因组分析显示，与 RT027（ST1）所有 MLST 分支 2 相比，有三个多基因座序列类型 (MLSTs 188、231 和 365)，有四个到五个基因座变异。艰难梭菌 RT251 菌株对甲硝唑、万古霉素和莫西沙星敏感，而 RT027 菌株通常对氟喹诺酮类抗菌药物耐药。需要使用全基因组测序进一步研究，以确定可能导致艰难梭菌 RT251 菌株致病性的其他毒力因子。
