Chalmers G, Bruce H L, Hunter D B, Parreira V R, Kulkarni R R, Jiang Y-F, Prescott J F, Boerlin P
Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada.
J Clin Microbiol. 2008 Dec;46(12):3957-64. doi: 10.1128/JCM.01548-08. Epub 2008 Oct 22.
Clostridium perfringens is an important pathogen of animals and humans and is the causative agent of necrotic enteritis (NE) in poultry. This study focuses on the typing of intestinal C. perfringens isolates (n = 61) from outbreaks of NE collected from several areas of Southern Ontario, using a recently developed multilocus sequence typing (MLST) technique. For comparison, C. perfringens isolates from healthy birds were also obtained and typed. An additional locus, the pfoS locus, was included in our analysis, in an attempt to increase the discriminatory ability of the method previously published. Birds were collected from two major poultry processors in Canada, and isolates from processor 2 formed a distinct MLST cluster. Isolates from healthy birds also collected from the outbreak flocks clustered together with isolates from the birds with NE. Although isolates from eight outbreaks clustered together, MLST types were also occasionally different between outbreaks. Strong linkage disequilibrium was observed between loci, suggesting a clonal C. perfringens population structure. Detection assays for toxin genes cpb2 (beta-2 toxin), tpeL, and the newly described netB (NetB toxin) were also performed. netB was almost always found in outbreak isolates, whereas cpb2 was found exclusively in healthy bird isolates. The toxin gene tpeL, which has not been previously identified in C. perfringens type A strains, was also found, but only in the presence of netB. Resistance to bacitracin was found in 34% of isolates from antimicrobial agent-free birds and in 100% of isolates from conventionally raised birds.
产气荚膜梭菌是人和动物的一种重要病原体，是家禽坏死性肠炎（NE）的致病因子。本研究聚焦于使用最近开发的多位点序列分型（MLST）技术，对从安大略省南部几个地区收集的NE暴发中分离出的肠道产气荚膜梭菌菌株（n = 61）进行分型。为作比较，还获取并分型了来自健康鸟类的产气荚膜梭菌菌株。我们的分析纳入了一个额外的基因座pfoS基因座，以试图提高先前发表方法的鉴别能力。从加拿大的两家主要家禽加工商处收集鸟类，来自加工商2的分离株形成了一个独特的MLST簇。从暴发鸡群中收集的健康鸟类的分离株也与NE鸟类的分离株聚集在一起。尽管来自8次暴发的分离株聚集在一起，但不同暴发之间的MLST类型偶尔也有所不同。在各基因座之间观察到强烈的连锁不平衡，表明产气荚膜梭菌具有克隆群体结构。还进行了毒素基因cpb2（β-2毒素）、tpeL和新描述的netB（NetB毒素）的检测分析。netB几乎总是在暴发分离株中发现，而cpb2仅在健康鸟类分离株中发现。毒素基因tpeL此前未在A型产气荚膜梭菌菌株中鉴定到，但仅在存在netB的情况下被发现。在来自无抗菌剂饲养鸟类分离株中有34%对杆菌肽耐药，而在传统饲养鸟类分离株中有100%对杆菌肽耐药。
