Clonal Relatedness of bla_OXA-58-carrying Acinetobacter baumannii Clinical Isolates

Objecitve To investigate the clonal relatedness of local bla_OXA-58-carrying Acinetobacter baumannii clinical isolates. Methods Non-duplicated isolates of Acinetobacter baumannii were collected in West China Hospital and verified by recA sequencing. Acquired bla_OXA-58 gene and natural bla_OXA-51/66 genes were detected by PCR. Strain typing for bla_OXA-58-carrying Acinetobacter baumannii isolates was performed by Enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR), multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). Results A total of 115 Acinetobacter baumannii isolates were verified by recA gene and bla_OXA-51/66 detection. Among them, nine (7.8%) isolates carry bla_OXA-58 with reduced susceptibility to imipenem (MIC ≥ 2 mg/L) were observed. ERIC-PCR fingerprints of nine bla_OXA-58-carrying isolates were highly similar. MLST revealed that eight isolates were ST95 and one isolate was ST75. PFGE showed that eight isolates with the same sequence type were of the same fingerprint types, which were of two closely-related subtypes. Conclusion In West China Hospital, some Acinetobacter baumannii isolates with reduced susceptibility to carbapenem carried bla_OXA-58. The major spread way of bla_OXA-58-carrying isolates was clonal dissemination.