Acinetobacter baumannii clonal lineages I and II harboring different carbapenem-hydrolyzing-β-lactamase genes are widespread among hospitalized burn patients in Tehran

Abstract

The aim of this study was to analyze antimicrobial resistance patterns and their encoding genes and genotypic diversity of Acinetobacter baumannii isolated from burn patients in Tehran, Iran. The presence of extended-spectrum beta-lactamase- and blaOXA-encoding genes among 37 multidrug resistant (MDR) A. baumannii strains isolated from patients hospitalized in a teaching hospital in Tehran was evaluated. Susceptibility to 7 antibiotics was tested by disk agar diffusion and to polymyxin B and colistin was tested by E-test, according to CLSI guidelines. All isolates were then analyzed by PCR for the presence of blaIMP, blaVIM, blaSIMblaOXA-23, blaOXA-24, and blaOXA-58-like carbapenemase genes, and blaOXA-51-like, blaTEM, blaSHV, blaPER, blaVEB, and blaGIM genes. Genotyping of A. baumannii strains was performed by repetitive sequence-based (REP)-PCR and cluster analysis of REP-PCR profiles. A. baumannii isolates were assigned to international clones by multiplex PCR sequence group analysis. Twenty-five A. baumannii isolates were classified as MDR, and 12 were classified as extensively drug resistant. All isolates were susceptible to colistin and polymyxin B. Eighty-one percent of the isolates was resistant to imipenem or meropenem and harbored at least one or both of the blaOXA-23-like or blaOXA-24-like carbapenemase genes. Co-existence of different resistance genes was found among carbapenem-resistant isolates. Multiplex PCR sequence group analysis most commonly assigned A. baumannii isolates to international clones I (18/37; 48.6%) and II (18/37; 48.6%). An alarming increase in resistance to carbapenems and the spread of blaOXA-23-like and/or blaOXA-24-like carbapenemase genes was observed among A. baumannii strains belonging to clonal lineages I and II, isolated from burn patients in Tehran.

Prevalence of carbapenem-resistant Acinetobacter baumannii from 2005 to 2016 in Switzerland

“…We confirmed the implication of carbapenem-resistant ACB complex isolates in the vast majority of clinical infections and nosocomial outbreaks that involved Acinetobacter isolates, as observed previously in Germany over a 5-year period [ 11 ]. Our findings were also in agreement with the known higher risk of infection by A. baumannii in burn patients in hospital settings, as already reported in Switzerland [ 12 ] and in other countries [ 13 , 14 ].…”

Phenotypic Detection of Β-Lactam Antibiotics, Methicillin and Inducible Clindamycin Resistance Among Bacterial Isolates in Patients with Otitis Externa

“…In this study, 41.7% of gram-negative bacteria, including A. baumannii, were MDR strains and 60% were positive simultaneously for metalo beta lactamase and AmpC production. Mahdian from Tehran and Khadidja from Aljazira reported that 70.3% and 93.6% of isolated A. baumannii from clinical specimens were found to be MDR strains (24,25).…”

Wide distribution of carbapenem resistant Acinetobacter baumannii in burns patients in Iran

“…Its infections have become critical challenge to health care systems due to increasing levels of resistance to antimicrobial agents in nosocomial isolates of A. baumannii ( Cai et al, 2012 ; Moradi et al, 2015 ). In developing countries, including Iran, the occurrence of carbapenem non-susceptinle A. baumannii (CNSAb) infections is a growing problem in hospitalized burn patients ( Mahdian et al, 2015 ; Zowawi et al, 2015 ). Inadequate management of the antibiotic therapy of CNSAb infections often leads to the emergence of extensive and pandrug resistant (XDR and PDR) CNSAb strains, which present significant health challenges by prolonging hospitalization, treatment failures, and increased mortality ( Liu et al, 2014b ).…”