Antibiotic Resistance Hotspot: Comparative Genomics Reveals Multiple Strains of Multidrug-Resistant Citrobacter portucalensis in Edible Snails

Abstract

The demand for terrestrial snails as a food source is still on the increase globally, yet this has been overlooked in disease epidemiology and the spread of antimicrobial resistance. This study conducted genomic analyses of twenty Citrobacter portucalensis strains isolated from live edible snails traded in two hubs. The isolates were subjected to MALDI-TOF MS, antimicrobial resistance testing, whole genome sequencing, and analyses for in-depth characterization. The findings disclosed that seventeen strains across the two trading hubs were distinct from previously reported ones. Four isolates were found to share the same sequence type (ST881). Genome-based comparison suggests a clonal transmission of strains between snails traded in these hubs. All the isolates across the two hubs harbored similar variety of antimicrobial resistance genes, with notable ones being blaCMY and qnrB. Sixteen isolates (80%) expressed phenotypic resistance to second-generation cephalosporins, while eleven isolates (55%) exhibited resistance to third-generation cephalosporins. This report of multi-drug-resistant C. portucalensis strains in edible snails highlights significant concerns for food safety and clinical health because of the potential transmission to humans. Enhanced surveillance and stringent monitoring by health authorities are essential to evaluate the impact of these strains on the burden of antimicrobial resistance and to address the associated risk.