Instituto de Innovación para la Producción Agropecuaria y el Desarrollo Sostenible (IPADS INTA-CONICET), Balcarce, Buenos Aires, 7620, Argentina.
Instituto de Agrobiotecnología y Biología Molecular, Instituto Nacional de Tecnología Agropecuaria, Consejo Nacional de Investigaciones Científicas y Técnicas (IABIMO INTA-CONICET), Hurlingham, Buenos Aires, Argentina.
Vet Res Commun. 2024 Feb;48(1):113-124. doi: 10.1007/s11259-023-10193-z. Epub 2023 Aug 7.
Campylobacter fetus spp. is a bacterium associated to reproductive losses in cattle worldwide. It is a venereal infectious disease known as bovine campilobacteriosis, with high impact mainly in countries with extensive production systems. Here, we show pathogenesis and diagnostic methods for Campylobacter fetus detection in cervico-vaginal mucus (CVM) samples from heifers experimentally infected and field cases from herds with low reproductive performance by campylobacteriosis infection. Bacterial culture, direct immunofluorescence test and qPCR were used as diagnostic methods to evaluate detection of C. fetus. In the experimental model 30 Aberdeen Angus and crossbred heifers and 4 Aberdeen Angus bulls for natural mating were assigned to 3 groups experimentally challenged with C. fetus subsp. fetus (Cff), C. fetus subsps venerealis (Cfv) and C. fetus subsp venerealis biovar intermedius (Cfvi), respectively, and a negative control group, all followed for 9 months. Also, field samples of CVM and aborted fetuses were recollected from seven beef cattle farms. Bacteriological culture had the higher C. fetus detection rate in CVM being the most appropriate, followed by qPCR (with commercial extraction DNA kit), direct immunofluorescence test and qPCR (with in-house extraction DNA method), in both, experimental model and field cases. From experimental model after natural mating, 62.5% and 25% heifers got pregnant from Cff and Cfvi groups, respectively, while from Cfv no pregnancy was detected. The strain more frequently detected was Cfvi, followed by Cff and Cfv. Colonization of Cff in female genital tract with high number of carriers and presence in aborted fetuses was evidenced, suggesting a high risk to bovine reproductive health. Bacteriemia was not detected after genital infection. Given the low detection rate of either test, we suggest the use of both, PCR based methods and bacterial culture could result in higher detection rate in farms with endemic campylobacteriosis.
胎儿弯曲菌 spp. 是一种与全球牛群生殖损失相关的细菌。它是一种性病传染病，称为牛弯曲菌病，在广泛生产系统的国家中影响较大。在这里，我们展示了在实验感染的后备牛颈阴道黏液 (CVM) 样本和由弯曲菌病感染引起低繁殖性能的牛群的现场病例中检测胎儿弯曲菌的发病机制和诊断方法。细菌培养、直接免疫荧光试验和 qPCR 被用作诊断方法来评估胎儿弯曲菌的检测。在实验模型中，30 头安格斯牛和杂交后备牛和 4 头安格斯公牛用于自然交配，分为 3 组，分别用胎儿弯曲菌亚种胎儿（Cff）、胎儿弯曲菌亚种 venerealis（Cfv）和胎儿弯曲菌亚种 venerealis 生物型 intermedius（Cfvi）进行实验挑战，以及阴性对照组，均随访 9 个月。此外，还从七个肉牛场采集了 CVM 和流产胎儿的现场样本。细菌培养在 CVM 中的胎儿弯曲菌检测率最高，是最适宜的方法，其次是 qPCR（使用商业提取 DNA 试剂盒）、直接免疫荧光试验和 qPCR（使用内部提取 DNA 方法），在实验模型和现场病例中均如此。在自然交配后的实验模型中，来自 Cff 和 Cfvi 组的 62.5%和 25%的后备牛怀孕，而来自 Cfv 的牛没有怀孕。检测到的菌株最频繁的是 Cfvi，其次是 Cff 和 Cfv。在雌性生殖道中检测到大量携带 Cff 的细菌定植，并在流产胎儿中存在，这表明对牛的生殖健康存在高风险。生殖器感染后未检测到菌血症。鉴于两种检测方法的检测率都较低，我们建议在地方性弯曲菌病的农场中同时使用基于 PCR 的方法和细菌培养，以提高检测率。
