Prevalence of Aminoglycoside Resistance and Aminoglycoside Modifying Enzymes in Acinetobacter baumannii Among Intensive Care Unit Patients, Ismailia, Egypt

BACKGROUND: Acinetobacter baumannii is an opportunistic pathogen that rapidly develops antibiotic resistance against commonly prescribed antimicrobial agents in hospitalized patients worldwide. Aminoglycosides are commonly used in the treatment of A. baumannii health care-associated infections (HAIs). Aminoglycosides resistance mechanisms are varied and commonly involve production of aminoglycoside-modifying enzymes (AME) and efflux systems. AIM: This study aimed to provide an insight into the frequency of genes encoding AME in A. baumannii strains isolated from different clinical specimens in intensive care units (ICU). METHODOLOGY: A total of 52 multidrug-resistant (MDR) A. baumannii strains were isolated from ICU, Suez Canal University Hospitals. Species identification and antibiotics susceptibility testing were done by the automated system VITEK 2. The genes encoding AME were detected by PCR. RESULTS: Aminoglycosides resistance (amikacin, gentamicin and tobramycin) was observed in 35 isolates (67.3%). We found that aacC1 gene was the predominant AME resistance gene among A. baumannii isolates, detected in 14 isolates (40%), aphA6 in 11 isolates (31.4%) and addA1 in 5 isolates (14.2%). We found 5 isolates containing 2 AME genes, 3 of them with aacC1 and aphA6 and the remaining 2 with both aacC1 and aadA1 genes. Nearly, 5 isolates (14.2%) were negative for all AME resistance genes. CONCLUSION: Our study indicated that AME encoding genes are predominant in A. baumannii strains in our region which stressed on the importance of preventive measures to control spreading of resistance genes.