Department of Veterinary Infectious Diseases and Avian Diseases, College of Veterinary Medicine and Center for Poultry Diseases Control, Chonbuk National University, Iksan, South Korea.
PLoS One. 2018 Oct 24;13(10):e0205324. doi: 10.1371/journal.pone.0205324. eCollection 2018.
Culture-based detection of Campylobacter can be affected by competing flora, temperature, incubation time, and presence of blood. The presence of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli in poultry has become one of the most common factors interfering with the detection of Campylobacter. In the present study, we evaluated potassium clavulanate (ESBL inhibitor) as a supplement in Bolton broth (C-Bolton broth) for enrichment and detection of Campylobacter. First, we determined growth kinetics of Campylobacter in the presence of different concentrations of ESBL E. coli in C-Bolton broth during enrichment. The effects of other factors such as incubation time, incubation temperature, and presence of blood on Campylobacter detection in C-Bolton broth were also investigated. The growth of Campylobacter co-cultured at a low concentration (2 and 4 log10 CFU/mL) of ESBL E. coli was similar to that of Campylobacter alone in C-Bolton broth, and Campylobacter co-cultured at a high concentration (6 and 8 log10 CFU/mL) of ESBL E. coli showed slower growth than the pure Campylobacter culture. The Campylobacter detection limit was 1 log10 CFU/mL when mixed with 2, 4, or 6 log10 CFU/mL of E. coli and 3 log10 CFU/mL when mixed with 8 log10 CFU/mL of E. coli after 48 h enrichment in the broth. Campylobacter detection from chicken feces and litter samples was not affected by incubation time, or presence of blood in the broth. A modified procedure of enrichment in C-Bolton broth at 37°C for 24 h without blood showed a significantly (P ≤ 0.05) higher detection rate and a lower false-negative rate than the ISO 10272-1:2006 method for Campylobacter detection from chicken feces and litter samples. In summary, the present study demonstrates the efficacy of Bolton broth supplemented with potassium clavulanate in the detection of Campylobacter mixed with ESBL E. coli, and an improved procedure to detect Campylobacter from chicken feces and litter samples.
基于培养的方法检测弯曲菌时，竞争菌群、温度、孵育时间和血液的存在等因素可能会对结果造成影响。产超广谱β-内酰胺酶（ESBL）的大肠杆菌在禽类中的存在已成为干扰弯曲菌检测的最常见因素之一。本研究评估了克拉维酸钾（ESBL 抑制剂）作为 Bolton 肉汤（C-Bolton 肉汤）添加剂，用于富集和检测弯曲菌。首先，我们在 C-Bolton 肉汤中不同浓度的 ESBL 大肠杆菌存在的情况下，确定了弯曲菌的生长动力学。还研究了孵育时间、孵育温度和血液存在等其他因素对 C-Bolton 肉汤中弯曲菌检测的影响。当与低浓度（2 和 4 log10 CFU/mL）的 ESBL 大肠杆菌共培养时，C-Bolton 肉汤中的弯曲菌生长与单独培养时相似，而与高浓度（6 和 8 log10 CFU/mL）的 ESBL 大肠杆菌共培养时，生长速度比纯弯曲菌培养物慢。当混合 2、4 或 6 log10 CFU/mL 的大肠杆菌时，肉汤中弯曲菌的检测限为 1 log10 CFU/mL，当混合 8 log10 CFU/mL 的大肠杆菌时，检测限为 3 log10 CFU/mL，48 小时富集后。从鸡粪便和垫料样品中检测弯曲菌不受孵育时间或肉汤中血液存在的影响。改良的 C-Bolton 肉汤在 37°C 孵育 24 小时，无血液的富集程序与 ISO 10272-1:2006 方法相比，从鸡粪便和垫料样品中检测弯曲菌的阳性检出率显著提高（P≤0.05），假阴性率降低。总之，本研究表明，在弯曲菌与 ESBL 大肠杆菌混合的情况下，补充克拉维酸钾的 Bolton 肉汤在检测弯曲菌方面是有效的，并且从鸡粪便和垫料样品中检测弯曲菌的方法得到了改进。
