ISCR2 is associated with the dissemination of multiple resistance genes among Vibrio spp. and Pseudoalteromonas spp. isolated from farmed fish.

58 multiresistant strains representing diverse genera were isolated from farmed fish in an aquaculture facility. Resistant rates of strains harboring ISCR2, an insertion sequence type element, were higher than those in which this element was absent. Full genome sequencing of a Vibrio isolate containing ISCR2 confirmed that it is associated with multiple resistance genes, many of which are of clinical relevance. We describe the structural variation within ISCR2, and its distribution throughout multiple diverse aquatic genera, including Vibrio, Shewenalla, Pseudoalteromonas and Psychrobacter, suggesting the potential role of ISCR2 in disseminating antibiotic resistance. We also observe, and experimentally verify, a novel macrolide resistance gene that is also associated with ISCR2.