Shewanella harboring antimicrobial and copper resistance genes in sea urchins (Paracentrotus lividus) from the Crozon peninsula (Brittany, France)

Abstract

Shewanella is a genus of aquatic non-fermenting Gram-negative bacteria with increasing numbers of reports of infections in humans and appearance of antimicrobial resistant strains. Cases of infection show a relatively strong association with seafood consumption or exposure to seawater. This study aimed to analyze Shewanella spp. isolated from the sea urchin Paracentrotus lividus collected from the Crozon peninsula (France) with the intention of obtaining insights into the role of this genus as a reservoir of antimicrobial and heavy metal resistance genes. Five among seven Shewanella isolates were resistant to antimicrobials, mainly to broad spectrum beta-lactams. Four isolates displayed multiple resistance to at least three of these antimicrobial classes: broad spectrum beta-lactams, aminoglycosides, macrolide, quinolones and/or tetracycline. Three antimicrobial resistance genes were detected in just one isolate encoding resistance to beta-lactam (blaSHV and blaTEM-1) and macrolide (ermB). In addition, the copper resistance gene cusB, was observed in this isolate which is also a plasmid carrier. Another copper resistance encoding gene, copA, was found among the isolates. These results indicate that the multidrug-resistant (MDR) Shewanella isolates and resistance genes could be potential risks to public health, due to the carrying of these MDR bacteria by sea urchins through human consumption.