Molecular and Phenotypic Characterization of Gentamicin Resistance in Clinical Acinetobacter Isolate
الموضوعات : Biotechnological Journal of Environmental MicroorganismsMasoumeh Ravand 1 , Seyede Tooba Shafighi 2
1 -
2 - Islamic Azad University, Rasht Branch, Department of Microbiology
الکلمات المفتاحية: Acinetobacter, Gentamicin, Ghenotypic, Molecular, aac (3)-IV,
ملخص المقالة :
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.
Rynga, D., Shariff, M., & Deb, M. (2015). Phenotypic and molecular characterization of clinical isolates of Acinetobacter baumannii isolated from Delhi, India. Annals of clinical microbiology and antimicrobials, 14(1), 40.
D'Souza, R., Pinto, N. A., Phuong, N. L., Higgins, P. G., Vu, T. N., Byun, J. H., ... & Yong, D. (2019). Phenotypic and genotypic characterization of Acinetobacter spp. panel strains: a cornerstone to facilitate antimicrobial development. Frontiers in Microbiology, 10, 559.
Valentine, S. C., Contreras, D., Tan, S., Real, L. J., Chu, S., & Xu, H. H. (2008). Phenotypic and molecular characterization of Acinetobacter baumannii clinical isolates from nosocomial outbreaks in Los Angeles County, California. Journal of clinical microbiology, 46(8), 2499-2507.
Sewunet, T., Asrat, D., Woldeamanuel, Y., Aseffa, A., & Giske, C. G. (2022). Molecular epidemiology and antimicrobial susceptibility of Pseudomonas spp. and Acinetobacter spp. from clinical samples at Jimma medical center, Ethiopia. Frontiers in microbiology, 13, 951857.
Zahra, N., Zeshan, B., Qadri, M. M. A., Ishaq, M., Afzal, M., & Ahmed, N. (2021). Phenotypic and genotypic evaluation of antibiotic resistance of Acinetobacter baumannii bacteria isolated from surgical intensive care unit patients in Pakistan. Jundishapur J. Microbiol, 14(4), e113008.
Tilahun, M., Gedefie, A., Seid, A., Debash, H., & Shibabaw, A. (2025). Prevalence of phenotypic drug resistance profiles and multi-drug-resistant Pseudomonas and Acinetobacter species recovered from clinical specimens in Ethiopia: a systematic review and meta-analysis. BMC Infectious Diseases, 25(1), 737.
