DNA Diagnostic A/S, Risskov, Denmark.
LVK Veterinary Cattle Practice, Hobro, Denmark.
J Appl Microbiol. 2022 Oct;133(4):2516-2527. doi: 10.1111/jam.15722. Epub 2022 Jul 31.
Diarrhoea is a common health problem in calves and a main reason for use of antimicrobials. It is associated with several bacterial, viral and parasitic pathogens, most of which are commonly present in healthy animals. Methods, which quantify the causative agents, may therefore improve confidence in associating a pathogen to the disease. This study evaluated a novel commercially available, multiplex quantitative polymerase chain reaction (qPCR) assay (Enterit4Calves) for detection and quantification of pathogens associated with calf-diarrhoea.
Performance of the method was first evaluated under laboratory conditions. Then it was compared with current routine methods for detection of pathogens in faecal samples from 65 calves with diarrhoea and in 30 spiked faecal samples. The qPCR efficiencies were between 84%-103% and detection limits of 100-1000 copies of nucleic acids per sample were observed. Correct identification was obtained on 42 strains of cultured target bacteria, with only one false positive reaction from 135 nontarget bacteria. Kappa values for agreement between the novel assay and current routine methods varied between 0.38 and 0.83.
The novel qPCR method showed good performance under laboratory conditions and a fair to good agreement with current routine methods when used for testing of field samples.
In addition to having fair to good detection abilities, the novel qPCR method allowed quantification of pathogens. In the future, use of quantification may improve diagnosis and hence treatment of calf diarrhoea.
腹泻是犊牛常见的健康问题，也是使用抗生素的主要原因。它与几种细菌、病毒和寄生虫病原体有关，其中大多数在健康动物中通常存在。因此，定量检测病原体的方法可能会提高将病原体与疾病联系起来的信心。本研究评估了一种新的商业上可用的、多重定量聚合酶链反应（qPCR）检测（Enterit4Calves），用于检测和定量与犊牛腹泻相关的病原体。
首先在实验室条件下评估该方法的性能。然后，将其与目前用于检测 65 头腹泻犊牛粪便样本和 30 份加标粪便样本中病原体的常规方法进行比较。qPCR 的效率在 84%-103%之间，检测限为每个样本 100-1000 个拷贝的核酸。从 42 株培养的目标细菌中获得了正确的鉴定，仅从 135 株非目标细菌中获得了一次假阳性反应。新型检测方法与当前常规方法之间的一致性 Kappa 值在 0.38 到 0.83 之间。
新型 qPCR 方法在实验室条件下表现良好，在用于测试现场样本时与当前常规方法具有良好的一致性。
除了具有良好的检测能力外，新型 qPCR 方法还可以定量检测病原体。在未来，使用定量检测可能会改善犊牛腹泻的诊断和治疗。
