Abstract

Background: Aminoglycosides are used as antibiotics in combination with beta-lactamas for many treatments of staphylococcal infections. Development of resistance in resistant strains can be done by enzymes produced by effective genes that cause the destruction of aminoglycoside antibiotics. The aim of this study was to investigate the prevalence of the aac (6 ') Ie / aph (2 "), aph (3') - IIIa1, ant (4 ') - Ia1 genes and mecA in staphylococcus strains which play an effective part in the resistance of aminoglycosides.

Materials and Methods: in this descriptive cross-sectional observation, 113 clinical samples including 68 isolate of Staphylococcus epidermidis and 45 isolate of Staphylococcus saprophyticus of 459 clinical samples were identified by biochemical and molecular tests. The antibiotic susceptibility pattern of isolates was determined using MIC method by E-test strips. Then, to determine the presence of genes responsible for resistance to aminoglycosides, gene-specific primers were used.

Results: Of 68 isolates obtained from saprophyticus Staphylococcus aureus, 39isolates(57.35%) were mecA gene. As well, 13 isolates (19.11%) have aac (6 ') Ie / aph (2 ") gene, 9 isolates (13.23%) have aph (3') - IIIa1 gene and 7 isolates (7.3%) have ant (4 ') - Ia1 gene. Of 45 isolates of Staphylococcus saprophyticus, 23 isolates(51.11%) have mecA genes, 8 isolates (17.77%) have aac (6') Ie / aph (2 ") gene, 4 isolates (8/8%) have aph (3 ') - IIIa1 gene and 2 isolates (4.4%) have gene ant (4') - Ia1 gen.

Conclusion: Statistical analysis showed that the prevalence of aminoglycoside genes is more among strains resistant to methicillin and this would suggest that methicillin-resistant strains are easy situation for the acquisition of resistance to other antibiotics.