Wheelhouse Nick, Hearn Jack, Livingstone Morag, Flockhart Allen, Dagleish Mark, Longbottom David
School of Applied Sciences, Edinburgh Napier University, Edinburgh, UK.
Vector Biology Department, Liverpool School of Tropical Medicine, Liverpool, UK.
J Appl Microbiol. 2022 Apr;132(4):2642-2648. doi: 10.1111/jam.15422. Epub 2021 Dec 28.
The order Chlamydiales comprises a broad range of bacterial pathogens and endosymbionts, which infect a wide variety of host species. Within this order, members of the family Parachlamydiaceae, which includes Parachlamydia and Neochlamydia species, have been particularly associated with infections in both humans and cattle, including having a potential pathogenic role in cases of bovine abortion. While the route of transmission has yet to be defined, it has been hypothesised that asymptomatic carriage and contamination of the immediate environment may be a route of inter-animal transmission. We investigated the asymptomatic carriage of Chlamydia-related organisms in healthy cattle.
METHODS & RESULTS: DNA was isolated from nasal and rectal swabs obtained from 38 healthy dairy heifers. A Chlamydiales sp. 16S rRNA qPCR was performed on each sample. A total of 18/38 nasal samples and all 38/38 rectal samples were identified as positive for Chlamydiales sp. Each positive sample was sequenced confirming the presence of DNA belonging to the Parachlamydiaceae.
The presence of Parachlamydiaceae DNA in nasal and rectal swab samples of healthy cattle provides evidence for the asymptomatic carriage of parachlamydial organisms within cattle.
SIGNIFICANCE & IMPACT OF THE STUDY: The study provides evidence of potential routes of environmental contamination that could provide a route for inter-animal and animal transmission of Parachlamydiaceae.
衣原体目包含广泛的细菌病原体和内共生体，可感染多种宿主物种。在这个目内，副衣原体科的成员，包括副衣原体属和新衣原体属，尤其与人类和牛的感染有关，包括在牛流产病例中可能具有致病作用。虽然传播途径尚未明确，但据推测，无症状携带和对直接环境的污染可能是动物间传播的一条途径。我们调查了健康牛中衣原体相关生物体的无症状携带情况。
从38头健康奶牛小母牛的鼻拭子和直肠拭子中分离DNA。对每个样本进行衣原体属16S rRNA定量聚合酶链反应。总共18/38份鼻拭子样本和所有38/38份直肠拭子样本被鉴定为衣原体属阳性。对每个阳性样本进行测序，确认存在属于副衣原体科的DNA。
健康牛的鼻拭子和直肠拭子样本中存在副衣原体科DNA，为牛体内副衣原体生物体的无症状携带提供了证据。
该研究为可能导致副衣原体科动物间传播和动物传播的环境污染潜在途径提供了证据。
