石家庄市零售鸡肉样品中弓形杆菌污染调查

目的调查石家庄市零售鸡肉中弓形杆菌的污染情况,为石家庄市弓形杆菌分布特征和防控提供基础数据支持。方法从石家庄市市内四区的菜市场、超市、连锁肉店随机购买零售鸡肉样品90份,应用驱动增强动力双孔滤膜法从样品中分离培养弓形杆菌,利用弓形杆菌多重聚合酶链式反应(PCR)检测及测序的方法对分离菌株进行种属鉴定,利用16S rDNA、rpoB基因测序的方法验证菌种鉴定结果。结果 90份鸡肉样品中,60份样品检出弓形杆菌86株,其中嗜低温弓形杆菌49株、布氏弓形杆菌37株,弓形杆菌检出率为66.67%(60/90)。60份阳性样品中,嗜低温弓形杆菌阳性样品45份(75.00%),布氏弓形杆菌阳性样品35份(58.33%)。嗜低温弓形杆菌和布氏弓形杆菌混合感染阳性样品20份,占比为22.22%(20/90)。不同采样点弓形杆菌检出率有较大差异。结论石家庄市零售鸡肉中弓形杆菌污染较重,嗜低温弓形杆菌污染率高于布氏弓形杆菌,两种弓形杆菌混合污染样品率较高。     

The introduction of Arcobacter spp. in poultry slaughterhouses

Despite the presence high levels of Arcobacter spp. on chicken carcasses, the source of arcobacter contamination in slaughterhouses still remains unclear. It has been hypothesised in the literature that Arcobacter species that contaminate carcasses originate in in-plant slaughterhouses and/or supply water. The present study aimed to determine the source of Arcobacter contamination in two poultry slaughterhouses in The Netherlands. Carcasses and intestinal tracts from 3 hen flocks and 2 broiler flocks were collected. Water draining off carcasses during processing in 2 slaughterhouses and supply water in one slaughterhouse were also taken. For one flock, cloacal swabs and faecal samples were taken on the farm before slaughtering. ERIC-PCR was applied to study the genetic diversity and relationship among the isolates. No Arcobacter spp. were found in the supply water but on almost all of the sampled carcasses and in carcass-draining-off water arcobacters were identified. Arcobacter spp. were detected in the gut systems of chickens, ranging from 20% to 85% in hens and 3.3% and 51% in broilers. Similar ERIC-PCR genotypes were detected in gut contents as well as on carcasses from the same flock. The present study demonstrated that Arcobacter spp. can be detected in chicken intestines at slaughter and could be brought in this way into slaughterhouses where the bacteria contaminate carcasses during processing.     

食品中弓形菌16S rRNA特异性扩增检测方法的建立

针对弓形菌16SrRNA基因合成1对引物,通过对聚合酶链式反应(PCR)扩增条件的优化,建立了检测弓形菌的PCR方法。3株弓形菌标准菌株PCR产物测序结果与NCBI上公布的弓形菌16S rRNA基因序列进行比对,比对结果表明3株弓形菌测序结果与NCBI上公布的弓形菌16S rRNA基因序列同源性均在99%以上。3株弓形菌标准菌株均特异性地扩增出了长度为1202bp的片段,其他19株不同种类的菌株均无扩增产物出现。55份食品样品用Johnson-Murano肉汤增菌后用此法进行检测,其中6份样品为弓形菌阳性,阳性率为10.9%。上述实验结果表明,方法特异性强、操作简便,节省了检测时间,可用于食品中弓形菌的快速检测。     

潜在食源性致病菌弓形菌在食品中的分布及检测研究进展

弓形菌（Arcobacter spp.）是一类重要的食源性致病菌,因其与弯曲菌（Campylobacter spp.）形态相似且亲缘关系很近,最初被称为“氧气耐受的弯曲菌”。弓形菌属内能够引起人致病的主要是布氏弓形菌、嗜低温弓形菌和斯氏弓形菌,感染致病性的弓形菌可以引起人类的肠炎、严重腹泻、败血症和菌血症等。弓形菌广泛存在于畜禽、畜禽产品和环境中,畜禽产品生产设备和水源的污染是造成其高感染率的主要途径。由于弓形菌的生理特征与弯曲菌相近,分离培养时通常较难与弯曲菌区分,分子生物学方法是弓形菌实验室诊断的主要手段。近年来,作为新型潜在的食源性致病菌,弓形菌逐渐引起研究者的关注。然而,相较于其他食源性致病菌,对弓形菌的研究尚处于起步阶段,国内的报道也相对较少。本文对弓形菌在食品中的污染现状、流行病学特点及弓形菌的实验室检测等相关研究进展进行综述,以期为广大研究者提供有价值的信息。     

PCR 法检测动物源性食品中布氏弓形菌

弓形菌是一种新型食源性致病菌,其中以布氏弓形菌污染率最高。本研究采用扩增23S rRNA的PCR法特异性检测布氏弓形菌,方法灵敏度可达103 CFU/mL。2株布氏弓形菌均特异性地扩增出了长度为2061 bp的条带;嗜低温弓形菌、斯氏弓形菌、空肠弯曲菌等共18株不同种类的菌株均无扩增产物出现,表明此PCR法能特异性的将布氏弓形菌鉴定到种一级水平。比较实验结果表明,API CAMPY鉴定试剂盒对于布氏弓形菌鉴定仅能到弓形菌属一级水平,本PCR法能实现布氏弓形菌种一级水平的鉴定,用于布氏弓形菌的检测具有优势。55份动物源性食品样品用Johnson-Murano肉汤增菌后用PCR法进行检测,其中5份样品为布氏弓形菌阳性,阳性检出率为9.1%。上述实验结果表明,本方法特异性强、操作简便,节省了检测时间,可用于动物源性食品中布氏弓形菌的快速检测。     

Arcobacter butzleri: Up‐to‐date taxonomy,ecology, and pathogenicity of an emerging pathogen

Arcobacter butzleri, recently emended to the Aliarcobacter butzleri comb. nov., is an emerging pathogen causing enteritis, severe diarrhea, septicaemia, and bacteraemia in humans and enteritis, stillbirth, and abortion in animals. Since its recognition as emerging pathogen on 2002, advancements have been made in elucidating its pathogenicity and epidemiology, also thanks to advent of genomics, which, moreover, contributed in emending its taxonomy. In this review, we provide an overview of the up‐to‐date taxonomy, ecology, and pathogenicity of this emerging pathogen. Moreover, the implication of A. butzleri in the safety of foods is pinpointed, and culture‐dependent and independent detection, identification, and typing methods as well as strategies to control and prevent the survival and growth of this pathogen are provided.     

Heat stress adaptation induces cross-protection against lethal acid stress conditions in Arcobacter butzleri but not in Campylobacter jejuni

The ability of many bacteria to adapt to stressful conditions may later protect them against the same type of stress (specific adaptive response) or different types of stresses (multiple adaptive response, also termed cross-protection). Arcobacter butzleri and Campylobacter jejuni are close phylogenetic relatives that occur in many foods of animal origin and have been linked with human illness (mainly diarrhoea). In the present study, sublethal stress adaptation temperatures (48 °C and 10 °C) and mild and lethal acid conditions (pH 5.0 and pH 4.0) were determined for A. butzleri and C. jejuni. In addition, it was evaluated whether these sublethal stress adaptations cause specific adaptive responses or cross-protection against subsequent mild or lethal acid stresses in these bacteria. The studies were conducted in broth adjusted to the different conditions and the results were determined by the dilution series plating method. It was shown that heat stress adapted A. butzleri (incubated for 2 h at 48 °C) were significantly more resistant to subsequent lethal acid stress (pH 4.0) than non-adapted cells at the 1 h time-point (p < 0.01 in Wilcoxon rank sum test). No specific adaptive responses against the stresses in A. butzleri or C. jejuni and no cross-protection in C. jejuni were found. The ability of heat stressed A. butzleri to tolerate later lethal acid conditions should be taken into account when designing new food decontamination and processing strategies.     

Prevalence of Arcobacter species in retail meats and antimicrobial susceptibility of the isolates in Japan

A survey was conducted to examine the prevalence of Arcobacter species among meat samples and to investigate the antimicrobial susceptibility of the isolates in Japan. In 1998 and 1999, samples of beef (n=90), pork (n=100) and chicken meat (n=100) were purchased from seven retail shops. Arcobacter species were isolated from 2.2%, 7.0% and 23.0% of beef, pork and chicken meat samples, respectively. The rate of isolations in chicken meats was shown to be significantly higher than those of beef and pork. Species-specific polymerase chain reaction (PCR) demonstrated that the most dominant Arcobacter species was Arcobacter butzleri among the isolates examined. Multiple contaminations with different Arcobacter species were observed in 5% of the chicken samples. Almost all the strains tested showed resistance to vancomycin (100%) and methicillin (97.5%). Strains resistant to cephalothin, sulfamethoxazole–trimethoprim, nalidixic acid and chloramphenicol were detected at the rate of 81.1%, 67.2%, 53.5% and 24.6%, respectively. All Arcobacter strains examined were susceptible to ampicillin, tetracycline, streptomycin and kanamycin.     

应用纤维膜过滤方法从鱼肠内容物中分离到一株布氏弓形杆菌

目的建立弓形杆菌的分离培养方法。方法通过纤维滤膜过滤的方法对菌悬液过滤,用CCDA平板对弓形杆菌进行分离培养。将分离到的可疑菌落进行分纯培养,然后通过生化和16SrRNA序列分析进行鉴定。结果从鱼肠内容物中分离到一株疑似菌株,对其进行表型生化分析和16SrDNA全序列分析,鉴定该菌为布氏弓形杆菌。结论该检验方法适用于对弓形杆菌进行分离培养。     

基于rpoB靶基因的PCR法快速检测弓形菌

建立了一种弓形菌(Arcobacter)快速、敏感、特异的PCR检测方法.采用PCR技术扩增弓形菌编码RNA聚合酶β亚基的rpoB基因,并对该方法进行特异性和敏感性测试.结果只有弓形菌在205bp处出现目的扩增带,其他菌株扩增结果均为阴性.该法对弓形菌的检测限可达8.20×102cfu/mL.建立的PCR方法具有操作简便、准确可靠以及灵敏特异的特点,为食品中弓形菌的快速检测提供了新的手段.