Research Information System
INDIAN JOURNAL OF MEDICAL MICROBIOLOGY, vol.47, pp.1-6, 2023 (SCI-Expanded)
Purpose: Vancomycin-Resistant Enterococci (VREs) have emerged and become a problem that threatens the health
of hospitalized patients. VRE can cause different serious infections of the urinary tract, the bloodstream, wound
and other body sites. VREs are resistant to multiple antibiotics and treatment options are very limited. We aimed
to investigate the efficacy of oritavancin and nisin alone and their combination against VRE strains.
Methods: VRE isolates from rectal swabs of hospitalized patients were identified by conventional and commercial
methods. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of oritavancin
and nisin against VRE strains were determined. The synergistic effect of both agent combinations was
examined by the Checkerboard test.
Results: All VRE strains were identifined as Enterococcus faecium. The MIC value of oritavancin was found in the
range of 0.015–0.24 μg/mL; in which 48 strains were susceptible (0.12 μg/mL) and two strains were resistant
(>0.12 μg/mL). The MBC of oritavancin was determined in the range of 0.06–3.84 μg/mL. The MIC of nisin was
found in the range of 12.5–100 μg/mL; in which 32 strains were susceptible (50 μg/mL) and 18 strains were
resistant (>50 μg/mL). MBC of nisin was determined in the range of 25–800 μg/mL. Two oritavancin resistant
strains were displayed indifference effect, whereas from 18 nisin resistant strains, 11 showed indifference, and
seven displayed synergistic effect. Thirty-eight out of 48 strains which were sensitive to oritavancin showed
indifference and 10 revealed synergistic effect, whereas 29 of 32 strains which were sensitive to nisin showed
indifference and three had synergistic effect.
Conclusions: A synergistic combination of oritavansin and nisin was detected in 20 strains (40%), Our study is the
first study in Turkiye.