First identification of bla(NDM-1) carbapenemase in bla(OXA-94)-producing Acinetobacter baumannii ST85 in Spain

Abstract

Introduction: NDM-1 carbapenemase is spreading rapidly all over the world, but this metallo-beta-lactamase has just been detected for the first time in an Acinetobacter baumannii (Ab) isolate of the ST85 clone in Spain. The aim of this study was to characterize a NDM-1-producing carbapenem-resistant A. baumannii (CR-Ab) isolate submitted to the Andalusian PIRASOA [infection prevention program] referral laboratory.

Methods: Carbapenemases were detected by PCR and Sanger DNA sequencing. Whole genome sequencing was performed by NGS (Miseq, Illumina). Resistance genes were identified with RESfinder, while MLSTfinder was used for sequence typing (ST). The genetic location of bla(NDM-1) was determined by nuclease S-1/PFGE/hybridization with specific probe.

Results: The isolate was susceptible to amikacin and tigecycline and belonged to the ST85 clone. bla(OXA-94) and bla(NDM-1) were identified by PCR and Sanger DNA sequencing, respectively. The resistance genes aadB, bla(ADC-25), bla(NDM-1), bla(OXA-94), msr(E), mph(E) and floR, sul2 were identified by NGS. The chromosome of the isolate contained a defective Tn125 transposon with bla(NDM-1) flanked by the insertion sequences ISAbA125 and ISAba14. The bla(NDM-1) gene was only detected in the chromosomal DNA.

Conclusion: This is the first time that bla(NDM-1) has been detected and characterized in a bla(OXA-94)-producing CR-Ab isolate belonging to the ST85 clone in Spain