Schallegger G, Muri-Klinger S, Brugger K, Lindhardt C, John L, Glatzl M, Wagner M, Stessl B
Department for Farm Animals and Veterinary Public Health, Institute of Milk Hygiene, Milk Technology, and Food Science, University of Veterinary Medicine, Vienna, Austria.
Veterinary Laboratory Diagnostics and Veterinary Practice Dr. Glatzl, Vienna, Austria.
Zoonoses Public Health. 2016 Dec;63(8):588-599. doi: 10.1111/zph.12267. Epub 2016 Apr 9.
Campylobacter spp. are important causes of bacterial zoonosis, most often transmitted by contaminated poultry meat. From an epidemiological and risk assessment perspective, further knowledge should be obtained on Campylobacter prevalence and genotype distribution in primary production. Consequently, 15 Austrian broiler flocks were surveyed in summer for their thermophilic Campylobacter spp. contamination status. Chicken droppings, dust and drinking water samples were collected from each flock at three separate sampling periods. Isolates were confirmed by PCR and subtyped. We also compared three alternative methods (culture-based enrichment in Bolton broth, culture-independent real-time PCR and a lateral-flow test) for their applicability in chicken droppings. Twelve flocks were found to be positive for thermophilic Campylobacter spp. during the entire sampling period. Seven flocks (46.6%) were contaminated with both, C. jejuni and C. coli, five flocks harboured solely one species. We observed to a majority flock-specific C. jejuni and C. coli genotypes, which dominated the respective flock. Flocks within a distance <2 km shared the same C. jejuni genotypes indicating a cross-contamination event via the environment or personnel vectors. Multilocus sequence typing (MLST) of C. jejuni revealed that the majority of isolates were assigned to globally distributed clonal complexes or had a strong link to the human interface (CC ST-446 and ST4373). The combination of techniques poses an advantage over risk assessment studies based on cultures alone, as, in the case of Campylobacter, occurrence of a high variety of genotypes might be present among a broiler flock. We suggest applying the lateral-flow test under field conditions to identify 'high-shedding' broiler flocks at the farm level. Consequently, poultry farmers and veterinarians could improve hygiene measurements and direct sanitation activities, especially during the thinning period. Ultimately, real-time PCR could be applied to quantify Campylobacter spp. directly from chicken droppings and avoid non-interpretable results achieved by culture-dependent methods.
弯曲杆菌属是细菌性人畜共患病的重要病因，最常见的传播途径是受污染的禽肉。从流行病学和风险评估的角度来看，应进一步了解弯曲杆菌在初级生产中的流行情况和基因型分布。因此，在夏季对15个奥地利肉鸡群进行了调查，以了解它们嗜热弯曲杆菌属的污染状况。在三个不同的采样期从每个鸡群中采集鸡粪、灰尘和饮用水样本。通过PCR对分离株进行确认并进行亚型分析。我们还比较了三种替代方法（在博尔顿肉汤中基于培养的富集法、非培养实时PCR法和侧向流动试验）在鸡粪中的适用性。在整个采样期内，发现12个鸡群的嗜热弯曲杆菌属呈阳性。7个鸡群（46.6%）同时被空肠弯曲菌和结肠弯曲菌污染，5个鸡群仅携带一种菌株。我们观察到大多数鸡群存在特定的空肠弯曲菌和结肠弯曲菌基因型，这些基因型在各自的鸡群中占主导地位。距离<2公里的鸡群共享相同的空肠弯曲菌基因型，表明通过环境或人员载体发生了交叉污染事件。空肠弯曲菌的多位点序列分型（MLST）显示，大多数分离株被归类为全球分布的克隆复合体，或与人类界面有很强的联系（CC ST-446和ST4373）。与仅基于培养的风险评估研究相比，这些技术的组合具有优势，因为就弯曲杆菌而言，肉鸡群中可能存在多种基因型。我们建议在田间条件下应用侧向流动试验，以在农场层面识别“高排泄”肉鸡群。因此，家禽养殖户和兽医可以改善卫生措施并直接进行卫生活动，尤其是在育肥期。最终，实时PCR可用于直接从鸡粪中定量弯曲杆菌属，并避免依赖培养方法获得的无法解释的结果。
