Departamento de Microbiología e Inmunología, Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, Apdo. Postal 124-F, Ciudad Universitaria, San Nicolás de los Garza, Nuevo León 66451, México.
J Food Prot. 2011 Feb;74(2):221-7. doi: 10.4315/0362-028X.JFP-10-282.
The microaerophilic nature of Campylobacter and its requirement of ∼5% O(2) for growth have complicated its recovery from foods. The addition to the enrichment media of oxygen quenchers such as charcoal or blood could interfere with PCR for its detection. In this study, a two-step simple aerobic method for Campylobacter detection is proposed. A modification of the Tran blood-free enrichment broth (BFEB), in which charcoal was excluded from the medium (M-BFEB), was compared with the original formulation and other enrichment broths. Campylobacter jejuni and Campylobacter coli were screened by PCR directly from the enrichment media. Various levels of pure cultures of C. jejuni and C. coli combined with Escherichia coli were inoculated into Preston, Bolton, BFEB, and the modified BFEB (M-BFEB). In addition, Campylobacter was inoculated onto retail purchased chicken skin and recovery was quantified. Rates of recovery after 24 to 48 h of enrichment at 42 °C under aerobic incubation for BFEB and M-BFEB and microaerobic incubations for Preston and Bolton broths were determined. Overall, our results indicated that the most sensitive medium was Bolton's, followed by either BFEB or M-BFEB; the least sensitive was Preston's. M-BFEB was directly coupled to a PCR assay to detect Campylobacter, avoiding intermediate plating. Campylobacter was detected in the presence of up to 10(8) E. coli cells per ml. M-BFEB facilitated detection of both C. jejuni and C. coli artificially inoculated onto chicken skin samples. M-BFEB coupled to PCR is a rapid and attractive alternative for isolation and identification of C. coli and C. jejuni from poultry.
弯曲菌的微需氧特性及其生长所需的约 5%氧气使其难以从食品中回收。在富集培养基中添加例如木炭或血液等氧气抑制剂可能会干扰其 PCR 检测。在本研究中，提出了一种两步简单需氧方法用于弯曲菌检测。改良的不含木炭的 Tran 无血富集肉汤（M-BFEB）与原始配方和其他富集肉汤进行了比较。通过 PCR 直接从富集培养基中筛选空肠弯曲菌和结肠弯曲菌。将不同水平的纯培养空肠弯曲菌和结肠弯曲菌与大肠杆菌混合后接种到 Preston、Bolton、BFEB 和改良的 BFEB（M-BFEB）中。此外，将弯曲菌接种到零售购买的鸡皮上，并定量回收。在 42°C 下有氧孵育 24 至 48 小时后，确定 BFEB 和 M-BFEB 以及 Preston 和 Bolton 肉汤的微需氧孵育条件下的回收率。总的来说，我们的结果表明最敏感的培养基是 Bolton 肉汤，其次是 BFEB 或 M-BFEB；最不敏感的是 Preston 肉汤。M-BFEB 直接与 PCR 检测法结合使用，可检测弯曲菌，避免了中间的平板划线步骤。即使存在高达 10^8 个/ml 的大肠杆菌细胞，也能检测到弯曲菌。M-BFEB 方便地检测了人工接种到鸡皮样本上的空肠弯曲菌和结肠弯曲菌。M-BFEB 与 PCR 结合是一种从家禽中分离和鉴定结肠弯曲菌和空肠弯曲菌的快速而有吸引力的替代方法。
