Document Type : Original Article


1 Bayer School of Natural and Environmental Sciences, Duquesne University, Pittsburgh, PA, USA

2 Department of Epidemiology and Biostatics, Research Centre for Emerging and Reemerging Infectious Diseases, Pasteur Institute of Iran, Tehran, Iran

3 Department of Medical Bacteriology, Faculty of Medicine, Shahed University, Tehran, Iran

4 Biotechnology and Biological Science Research Center, Faculty of Science, Shahid Chamran University of Ahvaz, Ahvaz, Iran

5 Tehran Heart Center, Cardiovascular Diseases Research Institute, Tehran University of Medical Sciences, Tehran, Iran

6 Department of Molecular and Cellular Sciences, Faculty of Advanced Science and Technology, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran

7 Department of Food Microbiology, School of Allied Medical Sciences, Iran University of Medical Sciences, Tehran, Iran

8 Department of Biotechnology, Faculty of Advanced Sciences and Technology, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran

9 Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran


Staphylococcus aureus is one of the most common infectious bacterial species and one of the agents of community-acquired infections (CAIs) and hospital-acquired infections (HAIs). Aminoglycosides are potent antibactericidal agents often used together with Beta Lactams or Glycopeptides, especially in treating Staphylococcal endocarditis. The present research aimed to determine the frequency of the aac (6 ́)-le-aph (2 ́ ́) gene that encodes Aminoglycoside modifying enzymes using PCR on clinical isolates of S. aureus. 115 clinical isolates of S. aureus were collected at educational hospitals in Karaj during 12 months. They were first identified by using standard biochemical and laboratory methods and, following CLSI principles and procedures, antibiotic sensitivity patterns of all isolates were obtained using the disc diffusion method. Moreover, using agar dilution, the minimum inhibitory concentration was determined using the antibiotic powder Gentamycin. Finally, gene frequency was measured by employing PCR. The highest levels of resistance to Aminoglycosides were observed in Kanamycin (47.8%), Gentamycin (46.9%), and Tobramycin (46.9%), and Doxycycline and Ciprofloxacin with 50.4 and 49.5 percent respectively, were the non-Aminoglycoside antibiotics to which the highest levels of resistance were exhibited. The frequency of the aac (6 ́)-le-aph (2 ́ ́) gene was 39.1 percent. Rapid and timely detection of resistant strains seems to be necessary in selecting suitable treatment options and in preventing the spread of resistance. Furthermore, rapid identification of genes that encode AME enzymes using PCR enjoys special advantages such as high levels of precision and speed.

Graphical Abstract

Frequency of aac (6 ́)-le-aph (2 ́ ́) gene and resistance to Aminoglycoside antibiotics in Staphylococcus aureus isolates


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Dr. Hoda Sabati
Shahid Chamran University of Ahvaz

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