Influence of different medium components on the in vitro activity of the growth-promoting antibiotic flavomycin against enterococci

The growth-promoting antibiotic flavomycin (also called bambermycin, flavop hospholipol and moenomycin) has a complex spectrum of activity against ente rococci, with some species being naturally resistant and others susceptible . In this study, proteins added to Mueller-Hinton ii medium had a strong de leterious effect on the activity of flavomycin, glucose had no effect and s tarch decreased the activity of flavomycin, The fatty substances Tween 80 a nd tributyrin increased the activity of flavomycin for several enterococcal species. Slight differences in the composition of the susceptibility test medium affected the MIC results obtained, indicating that strict standardiz ation of the test medium is necessary.