Prevalence of Genes Encoding Aminoglycoside-Modifying Enzymes and armA among Acinetobacter baumannii Clinical Isolates in Alexandria, Egypt.

Introduction: Acinetobacter baumannii (A.baumannii) is a ubiquitous pathogen responsible for serious infections in hospitalized patients with a high propensity to develop resistance to antimicrobial agents. The study aimed to determine the antimicrobial resistance patterns and the prevalence of aminoglycoside resistance genes among A. baumannii clinical isolates from patients in different intensive care units (ICUs) in Alexandria, Egypt.

Methods: A total of 100 A. baumannii isolates collected from ICU patients were confirmed as A. baumannii by VITEK 2 and the presence of the blaOXA-51 gene has been reported. Antimicrobial susceptibility testing was performed and Multiplex PCR was done for the detection of aminoglycoside resistance genes.

Results: Most of the isolates (82%) were resistant to all tested aminoglycosides; resistance was higher for kanamycin and neomycin, followed by amikacin. The predominant AMEs were aphA6 and aphA1 in 86% and 67% of the isolates, respectively; aacA4 and aacC1 were detected in 37% and 8%, respectively, while aadA1 and aadB were present in 34% and 4%, respectively. Furthermore, the armA gene was detected in 83% of the isolates.

Conclusion: The results of this study revealed a high level carriage of armA and AMEs, which limit the usage of aminoglycoside as a treatment option for A. baumannii and make treatment extremely difficult.