Journal of Research in Pharmacy Practice 1 1 2012 08 01 Double-disk synergy test for detection of synergistic effect between antibiotics against nosocomial strains of staphylococcus aureus 21 24 30082 EN . Rasool Soltani Department of Clinical Pharmacy and Pharmacy Practice, Isfahan University of Medical Sciences, Isfahan, Iran . Hossein Khalili Department of Clinical Pharmacy, Tehran University of Medical Sciences, Tehran, Iran . Fateme Shafiee Department of Clinical Pharmacy and Pharmacy Practice, Isfahan University of Medical Sciences, Isfahan, Iran Journal Article 2023 03 27 Objective: Synergistic effect between commonly used antibiotics against nosocomial <br />multidrug-resistant strains of Staphylococcus aureus, if present, could provide a viable <br />option as an alternative therapy for infections due to this pathogen. The aim of this study <br />was searching for any synergistic effect between several antibiotics against drug-resistant <br />strains of S. aureus with nosocomial origin using double-disk synergy test and to determine <br />the applicability of this test for such a purpose.<br />Methods: Over a 6-month period, strains of S. aureus isolated from clinical specimens <br />of hospitalized patients with documented nosocomial infection underwent disk diffusion <br />test using antibiotic disks of oxacillin, cephalothin, clindamycin, ciprofloxacin, vancomycin, <br />cotrimoxazole, rifampin, erythromycin, gentamicin and meropenem. Double-disk synergy test <br />was performed for all isolates resistant to at least two of applied antibiotics. Combinations <br />of all possible pairs of antibiotics (to which the microorganism was resistant) were tested <br />by placing antibiotic disks at distance of 20 mm from each other (center to center). After <br />16-20 hours of incubation, if synergistic effect was present among two antibiotics, an inhibition <br />zone was formed between their disks.<br />Findings: Among all of possible two-antibiotic combinations tested for 41 resistant isolates, <br />only two cases of synergistic effect were detected; both effects were among rifampin and <br />cotrimoxazole.<br />Conclusion: The combination of rifampin and cotrimoxazole could provide a viable option <br />for treatment of infections due to resistant strains of S. aureus; however, clinical trials are <br />needed before any new recommendation. Also, double-disk synergy test seems to be capable <br />of detecting the synergistic effect between antibiotics at in vitro level.<br /><br /> https://jrpp.mui.ac.ir/article_30082_28d89ee0086b8d5e875b59d3338f3d3a.pdf