Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, the Netherlands; WHO Collaborating Centre on Campylobacter and Antimicrobial Resistance from a One Health Perspective / WOAH Reference Laboratory for Campylobacteriosis, Utrecht, the Netherlands.
Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, the Netherlands; WHO Collaborating Centre on Campylobacter and Antimicrobial Resistance from a One Health Perspective / WOAH Reference Laboratory for Campylobacteriosis, Utrecht, the Netherlands.
J Microbiol Methods. 2024 Nov;226:107049. doi: 10.1016/j.mimet.2024.107049. Epub 2024 Sep 27.
Bovine Genital Campylobacteriosis (BGC) is caused by Campylobacter fetus subsp. venerealis and is a notifiable disease to the WOAH (World Organisation for Animal Health). For an effective BGC control program, the reliable differentiation of Campylobacter fetus subsp. venerealis (Cfv) from the closely related Campylobacter fetus subsp. fetus (Cff) is required. However, the available molecular C. fetus subspecies identification assays lack sensitivity and specificity to differentiate C. fetus isolates based on their phenotypic or genotypic differences. Furthermore, the current biochemical subspecies identification is not fully congruent with the genomic differentiation of C. fetus strains. In this study, the genome sequences of 41C. fetus strains with well identified subspecies, were analyzed with the large-scale BLAST score ratio (LS-BSR) pipeline to identify Cff and Cfv specific sequences. With this analysis, the asd gene encoding an aspartate-semialdehyde dehydrogenase was identified, which contained a 6-bp Cff-specific sequence, and this 6-bp sequence was absent in the asd gene of Cfv strains. This sequence was used for the development of PCR assays to differentiate Cff and Cfv strains. The C. fetus subspecies identification of the developed asd PCR assays was in full congruence with the genomic classification of strains and are recommended for molecular identification of C. fetus subspecies in BGC control programs. The asd PCR can be assessed on sequenced genomes using a web interface containing the Cfvcatch tool, which includes placement of the tested genome in a phylogenetic tree with reference C. fetus genomes to distinguish the two subspecies and to detect antimicrobial resistance genes.
牛生殖道弯曲杆菌病（BGC）由胎儿弯曲杆菌亚种 venerealis 引起，是世界动物卫生组织（WOAH）规定报告的疾病。为了实施有效的 BGC 控制计划，需要可靠地区分与密切相关的胎儿弯曲杆菌亚种 fetus（Cff）的胎儿弯曲杆菌亚种 venerealis（Cfv）。然而，现有的分子弯曲杆菌亚种鉴定检测在基于表型或基因型差异区分弯曲杆菌分离株方面缺乏敏感性和特异性。此外，当前的生化亚种鉴定与弯曲杆菌菌株的基因组分化不完全一致。在这项研究中，对 41 株具有明确亚种身份的弯曲杆菌菌株的基因组序列进行了分析，采用大规模 BLAST 评分比（LS-BSR）管道来识别 Cff 和 Cfv 特异性序列。通过该分析，鉴定出了编码天门冬氨酸半醛脱氢酶的 asd 基因，该基因包含一个 6bp 的 Cff 特异性序列，而 Cfv 菌株的 asd 基因中不存在该 6bp 序列。该序列被用于开发 PCR 检测方法来区分 Cff 和 Cfv 菌株。开发的 asd PCR 对菌株的弯曲杆菌亚种鉴定与基因组分类完全一致，建议在 BGC 控制计划中用于弯曲杆菌亚种的分子鉴定。asd PCR 可以在测序基因组上使用包含 Cfvcatch 工具的网络界面进行评估，该工具包括将测试基因组放置在参考弯曲杆菌基因组的系统发育树中，以区分两个亚种并检测抗生素耐药基因。
