Aminoglycoside Resistance Pattern among Hospital Acquired and Community Acquired Methicillin-Resistant Staphylococcus aureus

Abstract

Background: MRSA strains are now resistant many antibiotic groups, such as tetracyclines, aminoglycosides, and lincosamides, and become difficult to treat. Aminoglycosides are valuable antibiotics used for treatment of a variety of staphylococcal infections. Objectives: The aim of this study is to detect aminoglycoside resistance in various hospital acquired and community MRSA strain and to identify the genetic basis of this resistance. Methodology: MRSA strains were isolated and identified manually and VITEK 2 system, antibiotic susceptibility of the isolates was tested by VITEK 2 system and the MIC of various aminoglycosides was measured by E test. Conventional PCR was used to detect the genes responsible for aminoglycoside resistance among the isolates. Results: (33.3%) of CA- MRSA isolates were resistant to Amikacin, (20.8%) to Kanamicin and (37.5%) to Gentamicin, while (65.8%) of HAMRSA strains were resistant to Amikacin, (73.7%) to Kanamycin and (71.1%) to Gentamicin. the aac (6’)-Ie/aph (2”) gene was found in 58.3 % of the strains of CAIs and in 68.4% of the strains of HAIs. There is no significant difference between HAIs and CAIs harboring aac (6’)-Ie/aph (2”) gene (p value 0.419). While aph (3)-IIIa gene was found in 45.8% of the strains of CAIs and in 44.7% of the strains of HAIs. Conclusion: There was a non-significant difference between HAIs and CAIs harboring aph (3)-IIIa gene (p value 0.933). It is important to control development of aminoglycosideresistance in MRSA strains and to monitor the potential developing of new aminoglycoside resistant genes.