Chromosome-borne blaCTX-M-65 gene in non-O1/O139 Vibrio cholerae isolated from bile

Background and Objectives: Non-O1/O139 Vibrio cholerae (NOVC) has been associated with extraintestinal infections; however, its isolation from bile remains exceedingly rare. This study reports the identification and comprehensive analysis of a NOVC strain isolated from bile, including its antimicrobial resistance profile, virulence gene content, and molecular characteristics. Materials and Methods: A NOVC isolate was obtained from the bile of a patient with a hepatobiliary tumor. The isolate was identified and subjected to antimicrobial susceptibility testing. Whole-genome sequencing was performed to characterize its molecular features, including antimicrobial resistance genes, virulence genes, and relevant genetic mutations. Results: The NOVC isolate presents a multi-drug resistance phenotype. Corresponding genomic analysis indicates that thisstrain belongs to a novel sequence type (ST1736), carrying various drug resistance genes and virulence factors. Moreover,the blaCTX-M-65extended-spectrum β-lactamase (ESBL) gene was detected in its chromosomal genome. Conclusion: This study presents the first report of a multidrug-resistant NOVC strain isolated from bile in mainland China.Notably, the ESBL gene blaCTX-M-65was identified chromosomally in NOVC for the first time.