Department of Medicine & Epidemiology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
Department of Pathology, Microbiology & Immunology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
J Med Microbiol. 2021 Feb;70(2). doi: 10.1099/jmm.0.001293.
is frequently isolated from the eyes of cattle with infectious bovine keratoconjunctivitis (IBK; pinkeye). As with which has been causally linked to IBK, expresses an RTX (repeats in the structural toxin) cytotoxin that is related to cytotoxin. Pilin, another pathogenic factor in , is required for corneal attachment. Seven antigenically distinct pilin serogroups have been described in . Multiple different serogroups exist amongst type IV pilin encoded by , however, it is not known whether exhibits a similar degree of diversity in type IV pilin that it encodes. This study was done to characterize a structural pilin (PilA) encoded by isolated from cases of IBK to determine if diversity exists amongst PilA sequences. Ninety-four isolates of collected between 2002 and 2017 from 23 counties throughout California and from five counties in four other Western states were evaluated. DNA sequencing and determination of deduced amino acid sequences revealed ten (designated groups A through J) unique PilA sequences that were ~96.1-99.3 % identical. Pilin groups A and C matched previously reported putative PilA sequences from isolated from IBK-affected cattle in the USA (Virginia, Nebraska, and Kansas) and Asia (Kazakhstan). The ten pilin sequences identified were only ~74-76 % identical to deduced amino acid sequences of putative pilin proteins identified from the previously reported whole-genome sequences of derived from deep nasopharyngeal swabs of IBK-asymptomatic cattle. Compared to the diversity reported between structural pilin proteins amongst different serogroups of , PilA from geographically diverse isolates derived from IBK-affected cattle are more conserved.
常从患有传染性牛角膜结膜炎（IBK；红眼病）的牛的眼睛中分离出来。与已被因果关联到 IBK 的 一样， 表达一种 RTX（结构毒素中的重复）细胞毒素，与 细胞毒素相关。 中的另一种致病因子菌毛，是角膜附着所必需的。 在 中已经描述了 7 种抗原上不同的菌毛血清群。 在 编码的 IV 型菌毛中存在多种不同的血清群，然而，尚不清楚 是否在其编码的 IV 型菌毛中表现出相似程度的多样性。本研究旨在表征从 IBK 病例中分离的 编码的结构菌毛（PilA），以确定 PilA 序列是否存在多样性。从加利福尼亚州 23 个县和其他四个西部州的 5 个县收集的 94 株 于 2002 年至 2017 年进行评估。DNA 测序和推导的氨基酸序列确定揭示了 10 种（指定为 A 至 J 组）独特的 PilA 序列，这些序列的相似性约为 96.1-99.3%。菌毛组 A 和 C 与先前在美国（弗吉尼亚州、内布拉斯加州和堪萨斯州）和亚洲（哈萨克斯坦）从受 IBK 影响的牛中分离的 报道的推定 PilA 序列相匹配。鉴定出的 10 个菌毛序列与先前从 IBK 无症状牛的深鼻咽拭子中获得的 全基因组序列报告的推定 Pilin 蛋白的推导氨基酸序列的相似性仅为~74-76%。与不同血清群的结构菌毛蛋白之间报道的多样性相比，来自 IBK 受影响的牛的地理上多样化的分离株的 PilA 更为保守。
