Engström B E, Fermér C, Lindberg A, Saarinen E, Båverud V, Gunnarsson A
National Veterinary Institute, SE-751 89 Uppsala, Sweden.
Vet Microbiol. 2003 Jul 17;94(3):225-35. doi: 10.1016/s0378-1135(03)00106-8.
The bacterium Clostridium perfringens can cause both clinical and subclinical disease in poultry. To study the pathogenesis and epidemiology of disease caused by C. perfringens, methods for typing its various strains need to be evaluated. C. perfringens isolates from healthy and diseased poultry from different parts of Sweden were analysed by polymerase chain reaction (PCR) in order to establish the presence of alpha-, beta-, beta2-, epsilon -, iota- and enterotoxin genes. In order to subtype C. perfringens isolates, the two methods amplified fragment length polymorphism (AFLP) and pulsed field gel electrophoresis (PFGE) were compared on 21 C. perfringens isolates from 10 different farms. In a second study, 32 isolates of C. perfringens type A from three broilers from a healthy flock reared without ionophorous anticoccidials were subtyped by PFGE. All 53 isolates analysed with PCR belonged to the toxin type A of C. perfringens, with the gene coding for alpha-toxin production. Two isolates possessed the beta2-gene as well, but none had the other toxin genes. Both AFLP and PFGE differentiated 21 strains into 10 different subtypes. This differentiation correlated closely with the origins of the isolates. Unique subtypes were isolated from seven farms. Only isolates from birds of one farm demonstrated more than one subtype of C. perfringens. The subtyping of the isolates from a healthy flock showed that each bird carried two to three different subtypes and two different subtypes were found in the same kind of tissue sample in four cases. Three of the four different subtypes found in this study were new, compared with the first study. AFLP and PFGE were found to be equally suitable for subtyping of C. perfringens isolates. The wide variation in subtypes in the healthy broilers could be the result of the antibiotic-free rearing of these birds.
产气荚膜梭菌可在家禽中引起临床和亚临床疾病。为研究产气荚膜梭菌所致疾病的发病机制和流行病学，需要评估对其不同菌株进行分型的方法。通过聚合酶链反应（PCR）分析了从瑞典不同地区健康和患病家禽中分离出的产气荚膜梭菌，以确定α、β、β2、ε、ι毒素基因和肠毒素基因的存在情况。为了对产气荚膜梭菌分离株进行亚型分析，在来自10个不同农场的21株产气荚膜梭菌分离株上比较了扩增片段长度多态性（AFLP）和脉冲场凝胶电泳（PFGE）这两种方法。在第二项研究中，对来自一个未使用离子载体抗球虫药饲养的健康鸡群的三只肉鸡的32株A型产气荚膜梭菌分离株进行了PFGE亚型分析。用PCR分析的所有53株分离株均属于产气荚膜梭菌毒素A型，具有编码α毒素产生的基因。有两株分离株还拥有β2基因，但没有其他毒素基因。AFLP和PFGE均将21株菌株分为10个不同的亚型。这种分型与分离株的来源密切相关。从七个农场分离出了独特的亚型。只有来自一个农场的禽类分离株显示出不止一种产气荚膜梭菌亚型。对来自健康鸡群的分离株进行亚型分析表明，每只鸡携带两到三种不同的亚型，并且在四个案例中，同一种组织样本中发现了两种不同的亚型。与第一项研究相比，本研究中发现的四种不同亚型中的三种是新的。发现AFLP和PFGE同样适用于产气荚膜梭菌分离株的亚型分析。健康肉鸡中广泛的亚型差异可能是这些鸡无抗生素饲养的结果。
