LINEZOLID, QUINUPRISTIN/DALFOPRISTIN AND DAPTOMYCIN RESISTANCE IN VANCOMYCIN RESISTANT ENTEROCOCCI IN TEHRAN HOSPITALS

Background and Aim:This study aimed to determine the prevalence of linezolid, quinopristin/dalfopristin and daptomycin resistance among vancomycin resistant enterococci (VRE) isolated from various clinical specimens in selected Tehran hospitals.Methods:Between March 2015 and August 2017, 240 enterococci were isolated from different types of clinical specimens (urine (189), blood (32), abdominal fluid (10), CSF (5), wound (3) and others (11)). One hundred and seventy-four were enterococcus faecium (72.5%), 52 (21.7%) enterococcus faecalis and 14 were other species. E. faecium and E. faecalis isolates were tested for vancomycin resistance. The vancomycin resistant isolates were tested for linezolid, quinopristin/dalfopristin and daptomycin resistance by disk diffusion and micro-dilution methods.Results:Eighty (33.3%) of the isolates were resistant to vancomycin. All vancomycin resistant enterococci (VRE) were susceptible to both linezolid and daptomycin. Sixteen (9.1%) of vancomycin resistant enterococcus faecium (VREF) were resistant to quinopristin/dalfopristin (QD). Vat E gene which is the most common gene in QD enterococcal resistant strains was not detected. All E. faecalis isolates were resistant to QD, as expected.Conclusion:Although in this study, resistance to linezolid and daptomycin was not observed, but it must be administered with caution given that linezolid is used as the main treatment for VRE strains in our country, as a result of possible over-treatment, bacterial resistance is expected and the resistance to linezolid have been reported in neighboring countries. Thus clinicians may have to deal with linezolid resistant-VRE in the near future.

Keywords:

linezolid , VRE , enterococci