First report and characterization of a plasmid-encodedblaSFO-1in a multi-drug resistantAeromonas hydrophilaclinical isolate

Antibiotic resistance remains one of the most pressing public health issues facing the world today. At the forefront of this battle lies the ever-increasing identification of extended spectrum beta-lactamases and carbapenemases within human pathogens, conferring resistance towards broad-spectrum and last-resort anti-microbials. This study was prompted due to the identification of a pathogenic Aeromonas hydrophila isolate (strain MAH-4) collected from abdominal fluid, which presented a robust resistance pattern against second, third, and fourth generation cephalosporins, ertapenem, ciprofloxacin, gentamicin, levofloxacin and moxifloxacin, and beta lactam/beta-lactamase inhibitor combinations. Whole genome sequencing was performed and identified a 328 kb plasmid (pMAH4) encoding 10 antibiotic resistance genes, including bla SFO-1, bla TEM-1, and bla OXA-1 of A. hydrophia MAH-4. This is the first report of beta-lactamase SFO-1 within a clinical strain of Aeromonas . Due to the remarkable sequence identity of pMAH4 to plasmids associated with Enterobacterales genera like Klebsiella , and the extensive capabilities of Aeromonas for horizontal gene transfer, our identification of a clinical isolate encoding SFO-1 on a plasmid suggests ARG mobility between Enterobacterales and non- Enterobacterales species.