VanWorth C, McCrea B A, Tonooka K H, Boggs C L, Schrader J S
Department of Population, Health & Reproduction and Veterinary Extension, Veterinary Medicine Teaching and Research Center, University of California, Davis, Tulare 93274, USA.
J Food Prot. 2006 Feb;69(2):299-307. doi: 10.4315/0362-028x-69.2.299.
PCR-restriction fragment length polymorphism of the flagellin (flaA) gene in Campylobacter jejuni was used to determine the relationships of isolates collected at the farm and throughout processing for six niche-market poultry species. This study focused on two specialty chicken products, poussin and free range, and four other specialty products, squab, duck, guinea fowl, and quail. Cloacal and carcass samples were collected from three flocks from each of the six niche species. Three processing plants in California participated in a 2-year investigation. A total of 773 isolates from farm, posttransport, and the processing plants were genotyped, yielding a total of 72 distinct flaA profiles for the six commodities. Genetic diversity of C. jejuni at the farm was greatest for ducks with up to 12 distinct flaA types in two flocks and least for squab 1 flaA type between two farms. For two of the guinea fowl flocks, one free-range flock, two squab flocks, and all three poussin flocks, the flaA types recovered at the prepackage station matched those from the farm. Cross-contamination of poultry carcasses was supported by the observation of flaA types during processing that were not present at the farm level. New C. jejuni strains were detected after transport in ducks, guinea fowl, and free-range chickens. Postpicker, postevisceration, and prewash sampling points in the processing plant yield novel isolates. Duck and free-range chickens were the only species for which strains recovered within the processing plant were also found on the final product. Isolates recovered from squab had 56 to 93% similarity based on the flaA types defined by PCR-restriction fragment length polymorphism profiles. The 26 duck isolates had genetic similarities that ranged from 20 to 90%. Guinea fowl and free-range chickens each had 40 to 65% similarity between isolates. Poussin isolates were 33 to 55% similar to each other, and quail isolates were 46 to 100% similar. Our results continue to emphasize the need to clean processing equipment and posttransport crates in order to decrease cross contamination between flocks. This study also determined that several strains of C. jejuni had unique flaA types that could only be recovered in their host species.
空肠弯曲菌鞭毛蛋白(flaA)基因的聚合酶链反应-限制性片段长度多态性被用于确定六个小众市场家禽品种在农场及整个加工过程中所采集分离株之间的关系。本研究聚焦于两种特色鸡肉产品童子鸡和散养鸡,以及其他四种特色产品乳鸽、鸭、珍珠鸡和鹌鹑。从六个小众品种的每个品种的三个鸡群中采集泄殖腔和胴体样本。加利福尼亚州的三家加工厂参与了一项为期两年的调查。对来自农场、运输后及加工厂的总共773株分离株进行基因分型,六个商品总共产生了72种不同的flaA图谱。农场中空肠弯曲菌的遗传多样性在鸭中最大,两个鸡群中多达12种不同的flaA类型,在乳鸽中最小,两个农场之间只有1种flaA类型。对于两个珍珠鸡群、一个散养鸡群、两个乳鸽群和所有三个童子鸡群,在预包装站回收的flaA类型与农场中的相匹配。在加工过程中观察到农场层面不存在的flaA类型,这支持了家禽胴体存在交叉污染。在鸭、珍珠鸡和散养鸡运输后检测到新的空肠弯曲菌菌株。加工厂中的摘毛后、去内脏后和预清洗采样点产生了新的分离株。鸭和散养鸡是仅有的在加工厂内回收的菌株也在最终产品中被发现的品种。基于聚合酶链反应-限制性片段长度多态性图谱定义的flaA类型,从乳鸽中回收的分离株有56%至93%的相似性。26株鸭分离株的遗传相似性范围为20%至90%。珍珠鸡和散养鸡的分离株之间的相似性均为40%至65%。童子鸡分离株彼此之间的相似性为33%至55%,鹌鹑分离株的相似性为46%至100%。我们的结果继续强调清洁加工设备和运输后板条箱以减少鸡群间交叉污染的必要性。本研究还确定,几种空肠弯曲菌菌株具有独特的flaA类型,只能在其宿主物种中回收。