Prevalence of genes encoding aminoglycoside resistant in methicillin-sensitive Staphylococcus aurous and coagulase-negative staphylococci isolated from hospital infectious

 Introduction: Staphylococci are the most common causes of nosocomial infections are considered. Aminoglycosides are often used in combination with B-lactamas and glycopeptides for the treatment of endocarditis and bacteremia caused by Staphylococci. The main mechanism of aminoglycoside resistance in staphylococci is drug inactivation by cellular aminoglycoside modifying enzymes. Materials and Methods: 50 isolates of methicillin-sensitive Staphylococcus aureus and 50 isolates coagulase-negative staphylococci, were collected from various clinical specimens and were identified by standard biochemical tests. The antibiotic susceptibility pattern of isolates using the disk diffusion method and Etest for determining aminoglycoside antibiotics and the frequency of gene aac(6')-Ie-aph(2"), aph(3')-IIIa and ant(4')-Ia was determined using PCR. Results: 26% of the samples showed resistance to at least one antibiotics.Genes aac(6')-Ie/aph(2") and aph(3')-IIIa were most abundant genes, respectively. Approximately 14% of these genes were two samples simultaneously, but in no instance a gene ant(4')-Ia were found. Conclusion: High prevalence of genes aac(6')-Ie-aph(2") and aph(3')-IIIa resistance genes among isloate were found. Proper antibiotic can be prescribed to prevent dissemination of resistant strains. Use phenotypic and genotypic methods simultaneously give us full information of aminoglycoside resistance