IN-VITRO ACTIVITY OF RP-59500, A NEW SEMISYNTHETIC INJECTABLE PRISTINAMYCIN AGAINST STAPHYLOCOCCI

We compared the in vitro activity of RP 59500, a new streptogramin, wi th that of vancomycin and ciprofloxacin against 130 strains of S. aure us and 117 strains of coagulase-negative staphylococci, using the agar dilution method. The antistaphylococcal activity of RT 59500 was simi lar to that of vancomycin. All staphylococcal strains were inhibited b y less than or equal to 2 mu g/mL, including 61 methicillin-resistant S. aureus, 28 methicillin-resistant S. epidermidis and 23 methicillin- resistant S. haemolyticus strains. In contrast to ciprofloxacin, the i n-vitro activity of RP 59500 as well as of vancomycin remained almost unchanged, irrespective of the resistance phenotype for methicillin.