Molecular characterization of extended-spectrum beta-lactamases (ESBLs) produced by clinical isolates of Acinetobacter baumannii in Saudi Arabia

Abstract

BackgroundAcinetobacter baumannii is a common opportunistic pathogen that causes major nosocomial infections in hospitals. In this study, we hypothesized a high prevalence of A. baumanni ESBL (extended-spectrum beta-lactamase) among all collected isolates.MethodsA. baumannii isolates (n = 107) from ICU (Intensive care unit) of local hospitals in Makkah were phenotypically and genotypically characterized. The identity and antibiotic susceptibility of A. baumannii strains were determined using the Vitek-2 system. The identified ESBL producers were further analyzed by PCR and sequencing followed by MLST typing. blaTEM, blaSHV, and the blaCTX-M-group genes 1, 2, 8, 9, and 25 were investigated. Furthermore, blaOXA51-like and blaOXA23-like genes were also examined in the carbapenem-resistant A. baumannii isolates.ResultsOur data indicated a high prevalence of A. baumannii ESBL producers among the collected strains. Of the 107 A. baumannii isolates, 94 % were found to be resistant to cefepime and ceftazidime, and aztreonam using the Vitek 2 system. The genes detected encoded TEM, OXA-51-like and OXA-23-like enzymes, and CTX-M-group proteins 1, 2, 8, 9, and 25. MLST typing identified eight sequence type (ST) groups. The most dominant STs were ST195 and ST557 and all of them belong to worldwide clonal complex (CC) 2.ConclusionsThis study has shown that there is a high prevalence of antimicrobial resistance in A. baumannii. The diversity of STs may suggest that new ESBL strains are constantly emerging. The molecular diversity of the ESBL genes in A. baumannii may have contributed to the increased antimicrobial resistance among all isolates.

Prevalence of Extended-Spectrum β-Lactamases and Antibiotic Resistance Patterns in Acinetobacter baumannii Isolated from Clinical Samples in Kermanshah, Iran

“…Due to the widespread dissemination among nosocomial pathogens via plasmids and integrons, ESBL genes can cause further expansion of drug resistance, including MDR isolates (14,24). Various studies have reported frequencies of ESBL genes in A. baumannii ranging from 25% to 93.45% (25)(26)(27)(28). In the present study, among the 80 examined isolates of A. baumannii, 53.8% were ESBL producers, which is consistent with the results of previous studies.…”

Bacteriological profile and sensitivity pattern of microorganisms causing Urinary Tract Infection at a tertiary care center in eastern Uttar Pradesh

“…(84%) whereas, Alyamani et al, reported (94%). [25] The second higher producer of ESBL was Pseudomonas aeruginosa (73.07%), in contrast Shaikh et al, reported 25.13% ESBL prevalence, which is much lower than our finding. [26] This shows a rising trends of ESBL in these days and the reason may be indiscriminate and rampant use of cephalosporins for the treatment of common infections, as well as horizontal transmission of resistant genes among hospital acquired bacterial strains.…”

Occurrence and molecular characterization of metallo-β-lactamases (MBLs) among Acinetobacter baumannii isolates from cancer patients

“…The prevalence of imipenem-resistance among A. baumannii isolates was 99%. This rate is very high compared to resistance rates of clinical isolates reported few years ago from Jordan and neighboring countries which ranged between 90% to 64% [3,31,32,33]. A previous Jordanian study has also indicated that majority of Abaumannii isolates from environmental and clinical sources was multidrug resistant, except for colistin and tigecycline similar to the case in other countries such as Lebanon [3,32].…”