Molecular Detection of blaOXA-type Carbapenemase Genes and Antimicrobial Resistance Patterns among Clinical Isolates of Acinetobacter baumannii

Abstract

Acinetobacter baumannii is a bacterium found in most places, especially in clinics and hospitals, and an important agent of nosocomial infections. The presence of class D enzymes such as OXA-type carbapenemases in A. baumannii is proven to have a key function in resistance to carbapenem. The aim of the current study is to determine the blaOXA-type carbapenemase genes and antimicrobial resistance among clinically isolated samples of A. baumannii. We assessed 100 clinically isolated specimens of A. baumannii from patients in intensive care units of educational hospitals of Hamadan, West of Iran. The A. baumannii isolates' susceptibility to antibiotics was performed employing disk diffusion method. Multiplex polymerase chain reaction was used to identify the blaOXA-24-like , blaOXA-23-like , blaOXA-58-like , and blaOXA-51-like genes. The blaOXA-23-like , blaOXA-24-like , and blaOXA-58-like genes' prevalence were found to be 84, 58, and 3%, respectively. The highest coexistence of the genes was for blaOXA-51/23 (84%) followed by blaOXA-51/24-like (58%). The blaOXA-51/23- like pattern of genes is a sort of dominant gene in resistance in A. baumannii from Hamadan hospitals. The highest resistance to piperacillin (83%) and ciprofloxacin (81%) has been observed in positive isolates of blaOXA-23-like . The A. baumannii isolates with blaOXA-58-like genes did not show much resistance to antibiotics. Based on the results of the phylogenetic tree analysis, all isolates have shown a high degree of similarity. This study showed the high frequency of OXA-type carbapenemase genes among A. baumannii isolates from Hamadan hospitals, Iran. Thus, applying an appropriate strategy to limit the spreading of these strains and also performing new treatment regimens are necessary.

Emergence of NDM-1-producing Raoultella ornithinolytica from reservoir water in Northeast Thailand

“…bla SHV is recognized as the most prevalent ESBL gene that confers antibiotic resistance to pathogenic bacteria worldwide, primarily in E. coli and Klebsiella spp. [28][29][30][31], whereas bla OXA is typically identified in Pseudomonas aeruginosa [32] and Acinetobacter baumannii [33]. However, R. ornithinolytica harboring bla SHV and bla OXA has been isolated from a patient in China [34].…”

Sulbactam-durlobactam: A Step Forward in Treating Carbapenem-Resistant Acinetobacter baumannii (CRAB) Infections

“…Carbapenem resistance in A. baumannii is primarily caused by the horizontal acquisition of class D (OXA-type) carbapenemase genes [ 8 ]. Other mechanisms of carbapenem resistance include the acquisition of class B (VIM-, IMP-, and NDM-type) carbapenemases, loss of the outer membrane protein CarO, and modifications of the AdeABC resistance nodulation division efflux pump [ 9 ].…”