Provenzano Daniele, Turner Jeffrey W, Duran-Gonzalez Jorge, Laughlin David A, Kitaoka Maya, Unterweger Daniel, Silva David, Trevino Viviana, Gonzales Miguel F, Ermolinsky Boris, Pukatzki Stefan
School of Integrative Biological and Chemical Sciences, University of Texas Rio Grande Valley, One West University Blvd., Brownsville, TX, 78520, USA.
Department of Life Sciences, Texas A&M Corpus Christi, 300 Ocean Dr., Corpus Christi, TX, 78412, USA.
Sci Rep. 2025 Jul 2;15(1):23430. doi: 10.1038/s41598-025-04734-6.
The lifestyle of Vibrio cholerae is primarily environmental, yet a chance encounter with a human host can lead to cholera, a potentially lethal form of diarrhea. Strains belonging to O1 and O139 serogroups have pandemic potential, but the contribution of non-O1/non-O139 serovars towards the genesis of cholera remains unclear. Endemic V. cholerae lineages were investigated given several historical accounts describing cholera epidemics and sporadic, contemporary cholera-like outbreaks along the lower Rio Grande Delta (LRGD). Seven isolates were recovered from an urban segment of the Rio Grande and six from a rural segment where the river empties into the Gulf of Mexico. Urban isolates all encode ß-lactamase, and with one exception are phylogenetically closely related, rough (do not express O-antigen), harbor identical plasmids, exhibit a disabled Type VI Secretion System (T6SS), and decreased protease activity. In contrast, rural strains belong to distinct serogroups, are sensitive to ß-lactams, express proteases, and kill Escherichia coli in T6SS competition assays. Genome-scale phylogenetics and multilocus sequence typing indicate that urban and rural isolates belong to distinct and novel phylogroups. These results suggest that an urban niche heavily impacted by anthropogenic pressures and a downstream protected rural niche are inhabited by distinct V. cholerae phylotypes.
霍乱弧菌主要生活在环境中，但偶然接触人类宿主可能会导致霍乱，这是一种潜在致命的腹泻形式。属于O1和O139血清群的菌株具有大流行潜力，但非O1/非O139血清型对霍乱起源的贡献仍不清楚。鉴于有几份历史记录描述了沿里奥格兰德河下游三角洲（LRGD）的霍乱疫情以及零星的、当代类似霍乱的疫情爆发，对地方性霍乱弧菌谱系进行了调查。从里奥格兰德河的一个城市区域分离出7株菌株，从该河流入墨西哥湾的一个农村区域分离出6株菌株。城市分离株均编码β-内酰胺酶，除一株外，在系统发育上密切相关，粗糙（不表达O抗原），携带相同的质粒，表现出失活的VI型分泌系统（T6SS），且蛋白酶活性降低。相比之下，农村菌株属于不同的血清群，对β-内酰胺敏感，表达蛋白酶，并且在T6SS竞争试验中能杀死大肠杆菌。全基因组系统发育分析和多位点序列分型表明，城市和农村分离株属于不同的新型系统发育群。这些结果表明，受人为压力严重影响的城市生态位和下游受保护的农村生态位中栖息着不同的霍乱弧菌系统发育型。
