The aim of the current study was to describe the occurrence of the
blaOXA-23 gene and the ISAba1 element in imipenem-susceptible
Acinetobacter baumannii
strains. By performing the polymerase chain reaction mapping using combinations of ISAba1 forward primers and the
blaOXA-23-like gene reverse primers, we demonstrated that the ISAba1 element did not occur upstream of the
blaOXA-23 gene in five of 31 isolates, which explained the lack of resistance to imipenem despite the presence of the
blaOXA-23 gene. All of the
blaOXA-23-positive isolates were susceptible to imipenem and meropenem with minimal inhibitory concentration ≤4 µg/mL. Pulsed-field gel electrophoresis analysis revealed four genotypes among the five
blaOXA-23-positive isolates. The current report of the
blaOXA-23 gene in imipenem-susceptible isolates provided evidence that this gene may be silently spread in a hospital environment and highlighted the threat of undetected reservoirs of carbapenemase genes.
