Detection of blaOXA-23 and blaNDM-1 carbapenemase among clinical isolates of A. baumannii in Tabriz, north-west of Iran

Objectives: During recent years, multidrug-resistant Acinetobacter baumannii strains have become a serious threat to global health. Furthermore, the appearance of new resistant markers, such as New Delhi metallo-beta-lactamase (NDM-1) with the ability to hydrolyze a wide range of beta-lactams has limited the treatment process. Aim: This cross-sectional study was aimed to detect bla(OXA-23) and bla(NDM-1) carbapenemase genes among A. baumannii clinical isolates in Tabriz, North-west Iran. Methods: A total of 100 A. baumannii isolates were collected from Imam Reza Hospital of Tabriz city. Isolates were recognized by standard biochemical tests and molecular detection of bla(OXA-51) gene. Antimicrobial susceptibility profile was examined via the disk diffusion method. The presence of bla(OXA-23) and bla(NDM-1) resistance genes was determined by PCR and sequencing. Results: Overall, the highest resistance rate was against ciprofloxacin (95%), aztreonam (90%) and imipenem (82%) whereas the highest susceptibility was detected to gentamicin (65%). The frequency of MDR and XDR strains was 76% and 30%, respectively. All of carbapenem resistant isolates were carrying bla(OXA-23 )gene and only one of them (1%) was positive for bla(NDM-1) resistance gene. Conclusion: Our results are indicating a high incidence of bla(OXA-23 ) like gene and the emergence of bla(NDM-1) gene as a resistance factor to almost all antibiotics among the carbapenem resistant A. baumannii strains in our study region.