Molecular and Phenotypic Characterization of Gentamicin Resistance in Clinical Acinetobacter Isolate

Subject Areas : Biotechnological Journal of Environmental Microbiology

Masoumeh Ravand ¹ , Seyede Tooba Shafighi ²

1 -
2 - Islamic Azad University, Rasht Branch, Department of Microbiology & Genetic

Received: 2024-08-03 Accepted : 2024-08-24 Published : 2024-08-31

Keywords: Acinetobacter, Gentamicin, Ghenotypic, Molecular, aac (3)-IV,

Abstract :

Acinetobacter spp. are opportunistic nosocomial pathogens notorious for their multidrug resistance, complicating the treatment of infections such as bacteremia and pneumonia. The dissemination of aminoglycoside resistance genes, particularly via integrons, is a major therapeutic concern. This study aimed to characterize gentamicin resistance in clinical Acinetobacter isolates using phenotypic and molecular methods.
 Thirty Acinetobacter isolates were collected from medical centers in Lahijan and Amlash, Iran. Gentamicin resistance was phenotypically assessed by disk diffusion and macrodilution MIC methods per CLSI guidelines. Genotypically, the presence of the *aac(3)-IV* aminoglycoside resistance gene was detected by PCR following DNA extraction.
 Disk diffusion identified 40% of isolates as gentamicin-resistant. The macrodilution method confirmed resistance in 33.33% of isolates, with MIC values ranging from 7.81 μg/mL to 125 μg/mL. The *aac(3)-IV* gene was detected in 30% of all isolates.
 The high prevalence of the *aac(3)-IV* gene underscores its significant contribution to gentamicin resistance in these clinical isolates. Integrating molecular detection with phenotypic screening is crucial for surveillance and informs effective empirical therapy to combat multidrug-resistant Acinetobacter infections in the Guilan region.

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