# Genomic Insights into an Environmental Vibrio parahaemolyticus Biofilm Isolate: Deciphering Alternative Resistance Mechanisms and Mobilizable Genetic Elements

## TL;DR

This study explores how a Vibrio parahaemolyticus strain from a seafood market biofilm shows resistance through unique genetic features rather than typical antibiotic resistance genes.

## Contribution

The study reveals novel resistance mechanisms in environmental Vibrio parahaemolyticus strains, emphasizing biofilm adaptation and mobilizable genetic elements.

## Key findings

- Vaw-5 lacks common resistance genes like blaCARB and qnr but uses chromosomal changes and efflux pumps for resistance.
- The strain contains 16 unique transposons, including Tn5501 and Tn5393, linked to resistance gene mobilization.
- Vaw-5 has genomic islands and a plasmid with aac(2′)-Ia, supporting environmental adaptation and resistance.

## Abstract

Background/Objectives: Biofilms are key in spreading antibiotic resistance in various ecosystems. This study employed comparative genomics to examine the resistance and adaptability mechanisms of the Vibrio parahaemolyticus strain Vaw-5, isolated from a seafood market biofilm. Methods: A comparative examination of Vaw-5 and 32 publicly available V. parahaemolyticus genomes identified a distinct set of genetic resistance characteristics. Results: Unlike clinical strains, Vaw-5 lacks acquired antimicrobial resistance genes like the blaCARB and qnr variations. Instead, its resistance potential is based on chromosomal alterations, efflux pump systems (vmeAB, vcmD), and a unique repertoire of 16 strain-specific transposons, including Tn5501 and Tn5393, which are well-known vectors for antibiotic resistance gene (ARG) mobilization. Although not multidrug-resistant, Vaw-5 possesses unique genomic islands that share negligible homology with those of clinical strains, enriched with gene clusters for environmental adaptation, such as exopolysaccharide production and a fully functional Type VI Secretion System. Vaw-5 carries a distinctive plasmid with the resistance gene aac(2′)-Ia. Conclusions: Biofilm adaptation promotes structural integrity, inherent processes, and resistance above standard ARG acquisition. This study focuses on how biofilm communities in the food chain can operate as covert incubators for mobilizable resistance determinants, emphasizing the significance of ecological monitoring within a One Health paradigm to reduce possible public health hazards.