Limited genetic diversity and extensive antimicrobial resistance in clinical isolates of Acinetobacter baumannii in north-east Iran

Abstract

This study determined the mechanisms and patterns of antimicrobial resistance among the isolates obtained from different wards of a teaching hospital in the city of Mashhad in north-east Iran. Between January 2012 and the end of June 2012, 36 isolates of Acinetobacter baumannii were collected from different wards of Ghaem Hospital. Antimicrobial susceptibility testing and epsilometer testing (E-test) were performed. The genetic resistance determinants of A, B and D classes of b-lactamases, aminoglycoside modifying enzymes (AMEs), efflux pumps and ISAba1 elements were assessed by PCR. Repetitive extragenic palindromic element (REP)-PCR was performed to find the genetic relatedness of the isolates. Colistin was the most effective antibiotic of those tested, where all isolates were susceptible. E-test results revealed high rates of resistance to imipenem, ceftazidime and ciprofloxacin. The majority of isolates (97 %) were multidrug-resistant. OXA-51, OXA-23 and tetB genes were detected in all isolates, but OXA-58, IMP and tetA were not detected. The prevalence of OXA-24, bla TEM , bla ADC , bla VIM and adeB were 64, 95, 61, 64 and 86 %, respectively. ISAba1 was found to be inserted into the 59 end of OXA-23 in 35 isolates (97 %). Of the AMEs, aadA1 (89 %) was the most prevalent, followed by aphA1 (75 %). The band patterns reproduced by REP-PCR showed that 34 out of 36 isolates belonged to one clone and two singletons were identified. The results confirmed that refractory A. baumannii isolates were widely distributed and warned the hospital infection control team to exert strict measures to control the infection. An urgent surveillance system should be implemented.

Molecular characterization and genetic relatedness of clinically Acinetobacter baumanii isolates conferring increased resistance to the first and second generations of tetracyclines in Iran

“…Our results are also in agreement with a previous study by Farsiani et al [18] in 2015 who reported that the tetA gene was not found in any of the strains whereas tetB was detected in 100% of the strains. In our study, the increased level of resistance to tetracyclines was observed in spite of any detectable differences in prevalence of tetA and tetB in all of the isolates.…”

Evaluation of synergistic effect of tazobactam with meropenem and ciprofloxacin against multi-drug resistant Acinetobacter baumannii isolated from burn patients in Tehran

“…Our results indicated that all A. baumannii isolates were MDR and carbapenem resistant. The high prevalence of MDR A. baumannii strains is in accordance with the findings reported by Farsiani et al (97%) and Rynga et al (85%) in Iran and India, respectively [20], [21]. The global spread of MDR clones in healthcare settings has raised a great deal of concern, because carbapenem agents are commonly the first choice in the treatment of A. baumannii infections [22], [23].…”

Molecular mechanisms of antibiotic co-resistance among carbapenem resistant Acinetobacter baumannii

“…A study from China has reported the occurrence of tetA and tetB as 26.5% and 65.3% respectively [33]. A recent study from Iran has reported that tetA was not found and all 35 tetracycline-resistant A. baumannii isolates were found to possess the tetB gene [34]. Most of the trimethoprim-sulfamethoxazole resistant strains in this study i.e.…”