Mobile class A β-lactamase gene bla _GMA-1

Despite increasing reports, class A β-lactamases of environmental bacteria remain very poorly characterized, with limited understanding of their transmission patterns. To address this knowledge gap, we focused on a recently designated GMA family β-lactamase gene, bla _GMA-1, found in marine bacterial genera such as Vibrio. This study shows that gammaproteobacterial mobile class A β-lactamase is specialized for penicillin degradation, and bla _GMA-1 is frequently linked to strand-biased circularizing integrative elements (SEs) in sequences in the RefSeq/GenBank database. Evidence for the implication of SEs in β-lactamase environmental transmission provides insights for future surveillance studies of antimicrobial resistance genes in human clinical settings.