A review of the in-vitro activity of quinupristin/dalfopristin against intracellular pathogens and mycoplasmas.

Quinupristin/dalfopristin displays in-vitro bacteriostatic activity against all Legionella spp. (MICs = 0.06-2 mg/L), with Legionella pneumophila usually being at least two-fold more sensitive to quinupristin/dalfopristin than Legionella bozemanii, Legionella dumoffii, Legionella gormanii and Legionella micdadei (MIC = 0.

In-vitro and in-vivo antibacterial activity of quinupristin/dalfopristin.

Quinupristin/dalfopristin is a new water-soluble streptogramin antimicrobial agent comprising quinupristin and dalfopristin in a ratio of 30:70. The in-vitro spectrum of activity includes most multi-resistant Gram-positive aerobes, important Gram-negative aerobes, Gram-positive anaerobes and intracellular bacteria that are causal agents of respiratory, blood and cutaneous infections. Of particular note, quinupristin/dalfopristin is active against multidrug-resistant isolates of Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecium, and against penicillin-resistant and/or erythromycin-resistant Streptococcus pneumoniae.

In-vitro and in-vivo synergic activity and fractional inhibitory concentration (FIC) of the components of a semisynthetic streptogramin, RP 59500.

RP 59500 is a new semisynthetic injectable streptogramin antibiotic composed of two compounds which interact synergically, RP 57669 and RP 54476, derived from pristinamycin IA and pristinamycin IIB, respectively. The bacteristatic and bactericidal activities of RP 57669 and RP 54476 alone or combined in various proportions were tested by the chequerboard dilution technique. The fractional inhibitory concentration (FIC) index was determined for 14 Staphylococcus aureus isolates (including methicillin- and macrolide-resistant strains) and one culture collection strain.

Post-antibiotic effects of RP 59500 with Staphylococcus aureus.

The post-antibiotic effect (PAE) of the semisynthetic streptogramin RP 59500 was evaluated with four clinical isolates of Staphylococcus aureus (two strains susceptible to methicillin and to the macrolide-lincosamide-streptogramin B (MLSB) group and two strains resistant to these drugs). The PAE was defined as the time required for either the viable counts to increase by one log10 or for bacteria to regain their maximal rate of growth. Similar results were obtained regardless of which definition was used.