IN VITRO AND IN VIVO STUDIES ON ANTIBACTERIAL ACTIVITY OF FCE22250
Zhang Shu-hua,Ou Zhen-rong and Jin Yu-fang (Department of Pharmacology, Sichuan Ind Inst of Antibiotics, Chengdu 610051)
Results showed that FCE22250 had activityg aainst Gram-positive and Gram-negative bacteria in-vitro and in-vivo, especially Staphylococcus aureus. At a concentration of 0.005 to 0.125 μg/ml, FCE22250 inhibited 73.96% and 100% of the isolates of S. aureus and S. epidermidis respectively; and was active aainstg both Me-thicillin resistant and Penicillin resistant strains of S. aureus. At a concentration of 2 μg/ml and 5 μg/ml, it could inhibit 50% of Streptococcus spp. and Streptococcus faecalis tested. At 32 μg/ml., 80% of Pseudomonas aeruginosa and all of Escherichia coli, E. aerogenes and E.cloeceai and at 0.25 -16μg/ml, 100% of Shigella sppiand Salmonella spp. could be inhibited. In-vitro the activity of FCE22250 was similar to Rifapentine, and was less active than Rifampicin and Rifandin. It showed excellent therapeutic activity in experimental mice infected by Staph. aureus when the animals were treated by oral or subcutaneous route, the ED50 of FCE 22250 was 0.1 and 0.07mg/kg respectively. The antibacterial activity of FCE 22250 in-vivo is slightly less than that of Rifampicin.