Zhang Guodong, Ma Li, Doyle Michael P
Center for Food Safety, 1109 Experiment Street, University of Georgia, Griffin, Georgia 30223, USA.
J Food Prot. 2007 Apr;70(4):867-73. doi: 10.4315/0362-028x-70.4.867.
The objective of this study was to isolate from chickens potential competitive exclusion bacteria (CE) that are inhibitory to Campylobacter jejuni or Salmonella, or to both, for subsequent development of a defined CE product for use in poultry. Adult chickens from family farms, commercial farms, and broiler chicken research centers were sampled to identify and select C. jejuni-free donor chickens. A challenge treatment, which included administering perorally 106 CFU C. jejuni per chicken and determining undetectable cecal shedding of campylobacters at 4 weeks, was important for identifying the best CE donor chickens. Screening of bacterial colonies obtained from nine donor chickens by using selective and nonselective media yielded 636 isolates inhibitory to six C. jejuni strains in vitro, with 194 isolates being strongly inhibitory. Of the 194 isolates, 145 were from ceca, and 117 were facultative anaerobic bacteria. One hundred forty-three isolates were inhibitory to six strains of Salmonella (including five different serotypes) in vitro. Of these, 41 were strongly inhibitory to all C. jejuni and Salmonella strains evaluated, and most were Lactobacillus salivarius. A direct overlay method, which involved directly applying soft agar on plates with discrete colonies from mucus scrapings of gastrointestinal tracts, was more effective in isolating CE than was the frequently practiced isolation method of picking and transferring discrete colonies and then overlaying them with soft agar. The best approach for obtaining bacteria highly inhibitory to Salmonella and C. jejuni from chickens was to isolate bacteria from ceca under anaerobic conditions. Free-range chickens from family farms were better donors of potential CE strongly inhibitory to both Salmonella and Campylobacter than were chickens from commercial farms and broiler chicken research centers.
本研究的目的是从鸡群中分离出对空肠弯曲菌或沙门氏菌，或对两者均有抑制作用的潜在竞争性排斥细菌（CE），以便随后开发一种用于家禽的特定CE产品。对来自家庭农场、商业农场和肉鸡研究中心的成年鸡进行采样，以识别和选择无空肠弯曲菌的供体鸡。一种挑战处理方法很重要，即每只鸡经口给予106 CFU空肠弯曲菌，并在4周时确定盲肠中弯曲杆菌的不可检测性排菌，这有助于识别最佳的CE供体鸡。使用选择性和非选择性培养基对从9只供体鸡获得的细菌菌落进行筛选，在体外产生了636株对6株空肠弯曲菌菌株有抑制作用的分离株，其中194株具有强烈抑制作用。在这194株分离株中，145株来自盲肠，117株为兼性厌氧菌。143株分离株在体外对6株沙门氏菌菌株（包括5种不同血清型）有抑制作用。其中，41株对所有评估的空肠弯曲菌和沙门氏菌菌株均有强烈抑制作用，且大多数为唾液乳杆菌。一种直接覆盖法，即将软琼脂直接涂在含有来自胃肠道黏液刮片的离散菌落的平板上，在分离CE方面比经常采用的挑选和转移离散菌落然后用软琼脂覆盖的分离方法更有效。从鸡中获得对沙门氏菌和空肠弯曲菌有高度抑制作用的细菌的最佳方法是在厌氧条件下从盲肠中分离细菌。与来自商业农场和肉鸡研究中心的鸡相比，家庭农场的散养鸡是对沙门氏菌和弯曲杆菌均有强烈抑制作用的潜在CE的更好供体。
