Guevara Núñez Daiana, Morandini Fabrizzio N, Suleyman Geehan, Crooker Kyle, Kaur Jagjeet, Maki Gina, Bocco José L, Fernández Do Porto Darío, Zervos Markus J, Sola Claudia, Saka H Alex
Instituto de Química, Física de los Materiales, Medioambiente y Energía (IQUIBICEN), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina.
Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Provincia de Córdoba, Argentina.
Environ Microbiol Rep. 2025 Oct;17(5):e70181. doi: 10.1111/1758-2229.70181.
Vibrio cholerae is a globally distributed, free-living bacterium in aquatic ecosystems. While non-O1/non-O139 serogroups typically do not produce cholera toxin, they have the potential to cause diarrhoea. These strains may act as reservoirs of antibiotic resistance in rivers, lakes and oceans. Understanding their genetic resistance and virulence can shed light on their role in spreading antimicrobial resistance and their pathogenicity. In this study, we characterised 60 V. cholerae non-O1/non-O139 strains from 16 freshwater bodies located throughout the Province of Córdoba, Argentina. We found none of the strains carried cholera toxin and identified ampicillin resistance as the most prevalent phenotype. Whole genome sequencing revealed that all ampicillin-resistant strains (n = 10) carried CARB β-lactamases, leading to the identification of new CARB variants (CARB-59 to CARB-62) likely associated with the V. cholerae superintegron. Two strains were notably related and exhibited enhanced virulence due to an unusual genetic arrangement of the VPI-1 pathogenicity island, encoding both the toxin co-regulated pilus and a type VI secretion system cluster subclass i5, commonly found in non-cholera Vibrio species. These findings provide significant insights into the genetic diversity and virulent potential of ampicillin-resistant environmental V. cholerae non-O1/non-O139 and enhance our understanding of the evolution of CARB β-lactamases within the species.
霍乱弧菌是一种广泛分布于水生生态系统中的自由生活细菌。虽然非O1/非O139血清群通常不产生霍乱毒素，但它们有可能导致腹泻。这些菌株可能是河流、湖泊和海洋中抗生素耐药性的储存库。了解它们的遗传耐药性和毒力有助于揭示它们在传播抗菌药物耐药性及其致病性方面的作用。在本研究中，我们对来自阿根廷科尔多瓦省各地16个淡水水体的60株非O1/非O139霍乱弧菌进行了特征分析。我们发现所有菌株均未携带霍乱毒素，并确定氨苄西林耐药是最常见的表型。全基因组测序显示，所有耐氨苄西林菌株（n = 10）均携带CARBβ-内酰胺酶，从而鉴定出可能与霍乱弧菌超级整合子相关的新CARB变体（CARB-59至CARB-62）。有两株菌株显著相关，由于VPI-1致病岛的异常基因排列而表现出增强的毒力，该致病岛编码毒素共调节菌毛和VI型分泌系统簇亚类i5，常见于非霍乱弧菌物种。这些发现为耐氨苄西林环境非O1/非O139霍乱弧菌的遗传多样性和毒力潜力提供了重要见解，并增进了我们对该物种内CARBβ-内酰胺酶进化的理解。
