The combination of vancomycin and floxacillin inhibits cell growth in methicillin-resistant Staphylococcus aureus

BACKGROUND AND OBJECTIVESMethicillin-resistant Staphylococcus aureus (MRSA) is a serious threat regarding to nosocomial infections. Methicillin resistant (mecA), aminoglycoside resistant (aacA) and erythromycin resistant ermA are antibiotic resistant genes for MRSA. The combination of vancomycin with floxacillin can improve clinical outcomes. This study aimed to evaluate the frequency of antibiotic resistant genes and examine the combination effects of vancomycin and floxacillin against MRSA isolated from hospitalized patients in Gachsaran, Iran.MATERIALS AND METHODSIn this cross-sectional study of MRSA isolated and identified from patients with urinary tract infections, we set out to describe the frequency of antibiotic resistant genes, their antibacterial susceptibility patterns and combination effects of vancomycin and floxacillin according to standard guidelines.RESULTS AND DISCUSSIONAmong the ۹۰ clinical isolates of S. aureus, ۲۴ isolates were identified as MRSA by standard laboratory methods. The frequency of antibiotic resistant genes, mecA, aacA and ermA were ۱۷/۲%, ۸۶/۲% and ۴۸.۳%, respectively. Based on the susceptibility results, we observed ۹۳/۱% susceptibility to vancomycin. We found the highest rates of resistance to cefoxitin, oxacillin and ampicillin, respectively. Vancomycin showed synergistic (۶۸.۹۷%), and additive (۳۱.۰۳%) interaction with floxacillin against clinical isolates of MRSA.CONCLUSIONOur studies may well confirm that aacA and ermA may influence the antibiotic resistant in MRSA. In addition, we identified a potentially therapeutically significant combination of the vancomycin and floxacillin in MRSA.

کلیدواژه ها:

Combination therapy ، Floxacillin ، MRSA ، Vancomycin