War Wound Treatment Complications Due to Transfer of an IncN Plasmid HarboringblaOXA-181from Morganella morganii to CTX-M-27-Producing Sequence Type 131 Escherichia coli
ABSTRACTA 22-year-old male developed a recurrent sacral abscess associated with embedded shrapnel following a blast injury. Cultures grew extended-spectrum β-lactamase (ESBL)-producing, carbapenem-susceptibleEscherichia coli. Ertapenem was administered, but the infection recurred after each course of antibiotics. Initial surgical interventions were unsuccessful, and subsequent cultures yieldedE. coliandMorganella morganii, both nonsusceptible to carbapenems. The isolates were Carba NP test negative, gave ambiguous results with the modified Hodge test, and amplified theblaOXA48-like gene by real-time PCR. AllE. coliisolates were sequence type 131 (ST131), carried nine resistance genes (includingblaCTX-M-27) on an IncF plasmid, and were identical by genome sequencing, except for 150 kb of plasmid DNA in carbapenem-nonsusceptible isolates only. Sixty kilobases of this was shared byM. morganiiand represented an IncN plasmid harboringblaOXA-181. InM. morganii, the gene was flanked by IS3000and ISKpn19, but in all but one of theE. coliisolates containingblaOXA-181, a second copy of ISKpn19had inserted adjacent to IS3000. To the best of our knowledge, this is the first report ofblaOXA-181in the virulent ST131 clonal group and carried by the promiscuous IncN family of plasmids. The tendency ofM. morganiito have high MICs of imipenem, ablaOXA-181substrate profile that includes penicillins but not extended-spectrum cephalosporins, and weak carbapenemase activity almost resulted in the presence ofblaOXA-181being overlooked. We highlight the importance of surveillance for carbapenem resistance in all species, even those with intrinsic resistances, and the value of advanced molecular techniques in detecting subtle genetic changes.