Background & Aims : Aminoglycosides are powerful bactericidal agents used in combination with betalactams or gelicopeptitds, particularly in the treatment of staphylococcal infections. The main objective of this study was to investigate phenotypic and genotypic properties of aminoglycoside resistance in methicillin resistant S. aureus.

  Materials & Methods : During 8 months, out of 98 Staphylococcus isolates recovered from clinical samples, 53 cases were identified as MRSA. The sensitivity of these isolates to aminoglycosides investigated through disk diffusion method and MIC is determined. Presence of ant (4′)-Ia, aph(3′)-IIIa and aac(6′)/aph(2') genes were investigated through PCR method.

  Results : 77.3 and 26.4 percent of isolates were resistant to gentamicin and netilmicin, respectively. According to the PCR result, 77.3 percent of isolates have aac(6′)/aph(2′) genes,16.9 percent have aph(3′)-IIIa genes and 1.8 percent of them have ant(4′)-Ia genes. 16.9 percent of isolates have both aac(6′)/aph(2′ and aph(3′)-IIIa and 1.8 have all three kinds of genes.

  Conclusions : High MIC levels to aminoglycosides and high prevalence of aminoglycosides resistant genes were determined in s.aureus isolated from different wards indicates the aminoglycosides selection pressure resulted from high consumption of aminoglycosides in this hospital, which is an important point to be considered in the infection control policy.

  SOURCE: URMIA MED J 2014: 24(11): 893 ISSN: 1027-3727