Distribution of Aminoglycoside Resistance Genes Among Acinetobacter baumannii Strains Isolated From Burn Patients in Tehran, Iran

Background: Acinetobacter baumannii is an important cause of nosocomial infections, particularly in burn patients. Hospital Infections caused by these bacteria are difficult to treat. Objectives: The present study aimed at determining the frequency of genes encoding aminoglycoside-modifying enzymes in A. baumannii strains isolated from burn patients in Shahid Motahari hospital. Methods: This study was performed on 100 A. baumannii strains collected from Shahid Motahari hospital in Tehran during 2013 and 2014. The bacteria were cultured and identified. Antibiotic susceptibility testing was performed by disk diffusion method according to the CLSI guidelines. PCR assay was done to find the genes encoding aminoglycoside-modifying enzymes. Results: In this study, highest resistance to antibiotic was reported for ceftriaxone, ciprofloxacin, and ceftizoxime (100%), whereas the highest susceptibility was observed for colistin (100%), followed by gentamicin, amikacin, and tobramycin with (93%), (90%), and (87%), respectively. In the total of 100 strains studied, aphA6, aadB, aacC1 and aadA1 genes were found in 657 221 and 37 of A. baumannii isolates, respectively; 8 isolates had aadB and aphA6 genes and 3 had aadB, aadA1, aacC1, and aphA6 genes. Conclusions: This study showed the high frequency aminoglycoside-resistance genes among A. baumanni strains. Thus, the implementation of appropriate programs to prevent the spread of the bacteria seems necessary in the Shahid Motahari hospital.