不同品系养殖鸡弯曲菌感染调查

Campylobacter detection in laying hens and broilers from slaughterhouses

目的了解规模化养殖鸡弯曲菌感染现状。方法随机采集北京市某规模化养殖场蛋鸡(养殖时间大于120d)和肉鸡(养殖时间小于42d)肛拭子标本,采用两种分离培养方案(80份蛋鸡和200份肉鸡标本直接经选择性培养基划线培养,150份肉鸡标本经24h增菌后采用选择性培养基划线培养)进行弯曲菌的微需氧(5%O2、10%CO2和85%N2)培养。从肉鸡标本中随机选取50份,提取病原菌DNA,进行弯曲菌荧光定量PCR检测,并对相同培养条件下生长菌落进行质谱鉴定。结果 80份蛋鸡标本中分离到24株空肠弯曲菌,阳性率为30%;350份肉鸡标本未检测到弯曲菌。通过质谱菌落鉴定,205份标本检测到奇异变形杆菌,检出率为58.6%;145份标本检测到大肠埃希菌,检出率为41.4%。50份肉鸡粪便标本弯曲菌荧光定量PCR检测结果均为阴性,与分离培养结果一致。结论北京市规模化养殖蛋鸡弯曲菌感染率较高,饲养时间较短的肉鸡未发现弯曲菌感染。

Objective This study aims to investigate the prevalence of Campylobacter in laying hens and broilers. Methods Anal swabs were collected from laying hens （raised for longer than 120 days） and broilers （raised for fewer than 42 days）that were randomly selected from two slaughterhouses. A total of 280 swabs, including 80 samples from laying hens and 200 samples from broilers, were plated directly on Karmali selective plates and the remaining 150 swabs from broilers were placed in enriched medium to isolate Campylobacter in a microaerophilic atmosphere（5% O2, 10% CO2, and 85 % N2 ）. Pathogen DNA was extracted from 50 swabs for real time PCR analysis. Entire colonies were select ed according to their phenotype. Biochemical tests and multi-PCR were performed for to identify potential pathogens. Se lected colonies were examined using mass spectrometry. Results Twenty-four strains of C. jejuni were detected in the samples from 80 laying hens but no Campylobacter strains were detected from the 350 broiler chicken samples either by direct culture or by real time PCR. Of the 350 swabs from broilers, 205 were contaminated with Proteus mirabilis and the remainder were contaminated with Escherichia coli according to mass spectrometry. Conclusion Results indicated the contamination of that Campylobacter is more prevalent in laying hens than in broilers from slaughterhouses.