The assessment of novel antibiotics including daptomycin, linezole, quinopristin, and dalfopristin against methicillin-resistant Staphylococcus aureus isolated from the intensive care units of Sina Hospital, Tabriz

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) strains are frequently isolated from hospital infections. MRSA is resistant to multipe antibiotics, and limited options are available to treat infections caused by MRSA. Treatment using novel antimicrobial agets or using combiantion of two or more antibiotics is one of the therapeutic strategies to overcome MRSA. The aim of this study was to investigate the susceptibility to novel antibiotics daptomycin, linezolid, quinopristin and dalfopristin against MRSA collected from adult intensive care units (ICU) of Sina Hospital, Tabriz. Methods: Clinical specimens were inoculated on specific growth medium and bacterial isolates were identified using standard microbiology methods. Antibiotic resistance pattern of 12 investigated isolates was determined by disk diffusion method and minimum inhibitory concentration (MIC) was determined using E-test and microbroth dilution methods. The synergistic effects of the studied compounds were determined by determining the fractional inhibitory concentration index (FIC) using the Checkerboard method. Results: In the present study, high levels of antibiotic resistance were observed. None of the studied isolates were resistant to vancomycin, linezolid, daptomycin, quinopristin and dalfopristin. Significant synergistic effects were observed between vancomycin and rifampin, and cotrimoxazole and rifampin.