A Long-Term Study of the Diversity of OXA-48-Like Carbapenemase-Producing Bacterial Strains in Infected Patients and Carriers.

PURPOSE

Since their emergence at the beginning of the century, OXA-48 carbapenemases have spread in the community and in hospitals. To assess the diversity of OXA-48-producing bacterial strains and plasmids in the hospital setting, we studied the strains isolated from patients in three hospitals in the Paris area.

MATERIALS AND METHODS

All possible OXA-48-like strains were included in the study. OXA-48-like and extended-spectrum beta-lactamase-encoding genes were identified, and fingerprinting analysis was performed for all Escherichia coli and Klebsiella pneumoniae strains. The backbones and close genetic environments of bla were assessed by amplifying genes that were specific to the pOXA-48a plasmid and PCR, encompassing the junctions between bla and its direct genetic environment.

RESULTS

Overall, 68 strains from 30 patients were studied. These strains belonged to seven different enterobacterial species. OXA-48, OXA-204, and OXA-401 were identified in 62, 3, and 3 isolates, respectively. Additional broad-spectrum beta-lactamases were identified in 34% (23/68) of the strains. The strain diversity was high between and within patients. Identical patterns were observed only within individual patients or among epidemiologically related patients. Plasmid mapping was performed in the 62 OXA-48-producing strains and the 3 OXA-405-producing strains, resulting in the identification of 5 different patterns.

CONCLUSION

Because of their ability to transfer between strains, OXA-48 carbapenemases have a high risk of dissemination and may become endemic in France.