Abstract

In this study, extended spectrum beta-lactamase (ESBL) genes among Acinetobacter baumannii isolated from hospitalized patients with burn infections were evaluated. From December 2016 to March 2017, sixty-five isolates (72.2%) of A. baumannii were obtained from 90 burn samples of patients which were hospitalized in two hospitals in Baghdad, Iraq. The identification of A. baumannii strains was conducted by API 20NE and the presence of bla_OXA-51gene. Kirby-Bauer disc diffusion method was used for antibiotic susceptibility test. The frequency of ESBL producers was evaluated by double disk synergy test (DDST) and prevalence of bla_TEM, bla_SHV, bla_CTX-M genes were assayed by PCR. The results revealed that bla_OXA-51gene was found in all A. baumannii isolates as a species-specific gene. Of sixty-five isolates, 40 (61.53%) A. baumannii were ESBL producers according to DDST. High rates of resistance to cefotaxime, ceftazidime, piperacillin, and cefepime antibiotics were detected among ESBL producingA. baumannii isolates. The rate of resistance to other antibiotics was as the follows: 29(72.5%) to meropenem, 32(80%) to imipenem, 30 (75%) to piperacillin/tazobactam, 26 (65%) to ampicillin/sulbactam. The prevalence of bla_TEM, bla_CTX-M, bla_SHV genes among ESBL producing A. baumannii isolates was 30 (75%), 18 (45%) and 11 (27.5%) respectively. Our results demonstrated the role of bla_TEM gene in the resistance of beta-lactam antibiotics in the local strains of burn infections. The high rate of resistance in ESBL producing A. baumannii strains detected in this study highlights the necessity for the quick detection of ESBL isolates and the antimicrobial management, particularly in burn units.

Keywords

A. baumannii, ESBL genes, burns, ICU, DDST, CTX-M-type genes, sixty-five isolates, beta-lactam antibiotics, enterobacteriaceae, TEM-type, cephalosporins, carbapenems, oxacillin, trypticase soy broth, piperacillin/tazobactam, antibiogram disks