Preliminary characterization of Vibrio cholerae strains isolated from seafood samples marketed in Portugal

Vibrio cholerae , a natural inhabitant of aquatic ecosystems , has been related with gastrointestinal infections, particularly those associated with seafood consumption. This preliminary study aimed to evaluate the presence and characteristics of Vibrio cholerae, in seafood marketed in Portugal, given its potential role as a foodborne pathogen. Thus, the occurrence of Vibrio cholerae in 129 seafood raw samples (105 of shrimp and 24 of oysters), marketed in Portugal, was assessed. Isolates’ characterization regarding the presence of antimicrobial resistance (AMR) genes and of pathogenicity-specific genetic traits was attained by whole-genome sequencing (WGS). Core-genome Multi Locus Sequence Typing (cgMLST) analyses to evaluate the genetic relatedness among the isolates, and with other V. cholerae strains isolated in the world, as well as phenotypic AMR (performed by disc diffusion), were also attained. Overall, 43/129 (33.3 %) of the samples tested positive for V. cholerae (41/105 (39.1 %) of the shrimp and 2/24 (8.3 %) of the oysters’ samples). WGS analyses classified the studied strains as non-O1/non-O139 Vibrio cholerae (NOVC), lacking the main cholerae virulence factors encoded by the CTX phage. However, they carry diverse virulence factors similar to those found in O1 and O139 strains and/or in NOVC clinical strains. Furthermore, eight strains were classified as multidrug-resistant (MDR). The cg-MLST analyses revealed six genetic clusters among the 43 isolates (three identified sequence types - ST829, ST833, ST1085). Although it was not possible to find a close genetic relatedness between the studied V. cholerae strains and other deposited in PuBMLST database, a high genetic proximity among some strains isolated in different countries and from different sources (environmental and human) was observed, reinforcing the importance of a One Health approach. Assessing occurrence, pathogenic potential and genetic relatedness of Vibrio cholerae strains in the Portuguese food supply chain, this study contributes to understand their public health significance and supports a One Health approach to prevent foodborne outbreaks, contributing to food safety. • Non O1/non O139 V. Cholerae in 33.3 % of seafood samples marketed in Portugal. • Strains as reservoir of virulence and fitness genes, 21.0 % multidrug resistant. • Divergences between genome-based and phenotypic antimicrobial resistance. • Six cg-MLST clusters, three known STs identified (ST829, ST833, ST1085). • Genetic proximity among isolates from different countries/ sources.