Molecular Epidemiology of Extensively-DrugResistant Acinetobacter baumannii Sequence Type 2Co-Harboring blaNDM and blaOXA From ClinicalOrigin

Background: The therapeutic management of carbapenem-resistant Acinetobacter bauman-nii (CR-AB) represents a serious challenge to the public health sector because these patho-gens are resistant to a wide range of antibiotics, resulting in limited treatment options. Thepresent study was planned to investigate the clonal spread of CR-AB in a clinical setting.Methodology: A total of 174 A. baumannii clinical isolates were collected from a tertiarycare hospitals in Lahore, Pakistan. The isolates were confirmed by VITEK 2 compact systemand molecular identification of recA and blaOXA-51. Antimicrobial profile and the screeningof carbapenem-resistant genes were carried out using VITEK 2 system and PCR, respec-tively. The molecular typing of the isolates was performed according to the Pasteur scheme.Results: Of the 174 A. baumannii isolates collected, the majority were isolated from sputumsamples (46.5%) and in the intensive care unit (ICU, 75%). Among these, 113/174 (64.9%)were identified as CR-AB, and 49.5% and 24.7% harbored blaOXA-23 and blaNDM-1, respec-tively. A total of 11 (9.7%) isolates co-harbored blaOXA-51, blaNDM-1, and blaOXA-23.Interestingly, 46.9% of the CR-AB belonged to sequence type 2 (ST2; CC1), whereas15.9% belonged to ST1 (CC1). All of the CR-AB isolates showed extensive resistance toclinically relevant antibiotics, except colistin