Silva Marta F, Pereira Ana L, Fraqueza Maria J, Pereira Gonçalo, Mateus Luísa, Lopes-da-Costa Luís, Silva Elisabete
CIISA-Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, Av. da Universidade Técnica de Lisboa, 1300-477 Lisboa, Portugal.
Microorganisms. 2021 Feb 9;9(2):340. doi: 10.3390/microorganisms9020340.
The pathogenesis mechanisms of subsp. (), the etiologic agent of Bovine Genital Campylobacteriosis remain elusive. This study evaluated the virulence potential and biovar characteristics of isolates ( = 13) by PCR screening of putative virulence-factor (VF) genes, Multilocus Sequence Typing (MLST) analysis, antimicrobial susceptibility to tetracycline, penicillin, enrofloxacin and streptomycin testing and whole-genome sequencing (WGS; = 5), also comparing the latter with 26 other whole-genome sequences of strains. The putative VF genes encoding type IV secretion system of (-/) were absent in 92% of isolates, including isolates from aborted foetuses, evidencing that these VF genes are not essential for pathogenicity. The gene, used as a diagnostic molecular target, was detected in only 3 of 13 isolates, invalidating its use for diagnosis purposes. Three novel sequence types were identified by MLST. Although no in vitro antimicrobial resistance was detected, WGS identified antimicrobial resistance-related genes, including those encoding the multidrug efflux pumps CmeABC and YkkCD, indicating that their presence is not enough to provide antimicrobial resistance. The SNP and accessory protein families analysis segregated the and biovar intermedius () strains into different clusters. In conclusion, this study evidenced virulence potential and biovar characteristics of and , which are of relevance for the control of Bovine Genital Campylobacteriosis.
牛生殖道弯曲菌病的病原体弯曲菌亚种（）的致病机制仍不清楚。本研究通过对假定毒力因子（VF）基因进行PCR筛选、多位点序列分型（MLST）分析、检测对四环素、青霉素、恩诺沙星和链霉素的抗菌敏感性以及全基因组测序（WGS；n = 5），评估了弯曲菌分离株（n = 13）的毒力潜力和生物变种特征，还将后者与其他26个弯曲菌菌株的全基因组序列进行了比较。编码弯曲菌IV型分泌系统（- /）的假定VF基因在92%的分离株中缺失，包括来自流产胎儿的分离株，这表明这些VF基因对弯曲菌的致病性并非必不可少。用作弯曲菌诊断分子靶点的基因仅在13株分离株中的3株中检测到，因此不能将其用于诊断目的。通过MLST鉴定出三种新的序列类型。虽然未检测到体外抗菌耐药性，但WGS鉴定出了与抗菌耐药性相关的基因，包括编码多药外排泵CmeABC和YkkCD的基因，这表明这些基因的存在不足以导致抗菌耐药性。单核苷酸多态性（SNP）和辅助蛋白家族分析将弯曲菌和中间生物变种（）菌株分为不同的簇。总之，本研究证明了弯曲菌和的毒力潜力及生物变种特征，这对牛生殖道弯曲菌病的控制具有重要意义。
