Antimicrobial resistance of <i>Vibrio</i> spp. from the coastal California system: discordance between genotypic and phenotypic patterns

Vibriosis (infection with non-cholera <i>Vibrio</i> spp.) is the most common seafood-borne illness globally, with major impacts on public health, food security, and wildlife health. Potential treatments of antimicrobial-resistant <i>Vibrio</i> spp. in humans, aquaculture, and marine wildlife rehabilitation are complicated by current diagnostic challenges regarding bacterial species identification and interpretation of antimicrobial resistance patterns. Unexpected detection of previously misidentified <i>Vibrio diabolicus</i> in sea otters suggests that a broader taxonomic group of <i>Vibrio</i> infect sea otters than previously described. We also determined that the presence of ß-lactamase genes alone in sea otter isolates does not necessarily correlate with an ampicillin-resistant phenotype, likely due to deleterious amino acid substitutions in certain <i>bla</i>_CARB alleles. Continued monitoring of <i>Vibrio</i> spp. phenotypes and genotypes in sea otters is warranted to observe biologically relevant changes in antimicrobial resistance.