Assessment of antibiotic sensitivity as single agent and combination of antibiotics against vancomycin-resistant Enterococci (VRE), isolated from clinical specimens collected from Sina Hospital, Tabriz during 2021-2022

Abstract

Enterococci are cocci and facultative anaerobes that are frequently isolated from hospital infections. Vancomycin-resistant Enterococcus isolates are resistant to most antibiotics, and limited options are available to treat infections caused by these strains. One of the treatment solutions to overcome vancomycin-resistant Enterococcus strains is to use a combination of two or more different antibiotics. The purpose of this study is to investigate the effects of combinations of rifampin and vancomycin and fosfomycin and vancomycin in laboratory conditions against vancomycin-resistant Enterococcus isolates. Methods: Clinical specimens were inoculated on specific growth medium and bacterial isolates were identified using standard microbiological methods. Antibiotic resistance patterns of isolates were determined by disk diffusion method, and minimum inhibitory concentration was determined by microbroth dilution method. The synergistic effects of the studied compounds were determined by determining the FIC index using the Checker Board method. Results: In the present study, high levels of antibiotic resistance were observed. None of the studied isolates were resistant to linezolid. Antimicrobial antagonism effects were not observed in any of the combination. The most synergistic effects were in the combination of fosfomycin and necomycin, followed by rifampin and vancomycin.