Fatal bacteremia caused by novel sequence type 1665 of non-O1/non-O139 Vibrio cholerae: a case report and literature review

Non-O1/non-O139 Vibrio cholerae (NOVC) have been observed sporadically worldwide, causing a spectrum of illnesses ranging in severity from mild to life-threatening, despite the absence of the ctx virulence gene. Here, we report a fatal case of NOVC bacteremia in a 72-year-old woman with no obvious underlying diseases. The isolate, designated as V. cholerae vc973360, was classified as a novel sequence type 1665, by whole genome sequencing. Notably, vc973360 lacked the ctxAB genes but contained 147 other potential virulence factors, including hlyA, tlh, and rtx. Additionally, this isolate encodes three putative O-antigen ORFs of Yersinia origin, representing a unique genomic feature within the Vibrio genus. It also carried several resistance genes, such as qnrVC4, CRP, almE, almF, almG. However, the isolate’s susceptibility profile indicated that it was susceptible to the majority of antimicrobials tested except polymyxin B. Phylogenetic analysis revealed that vc973360 was most closely related to a clinical isolate recovered from human blood in Colombia. The patient had severe symptoms and succumbed to the infection, underscoring the need for comprehensive exploration of both clinical manifestations and epidemiological factors to facilitate early diagnosis and establish effective therapeutic strategies.