INHIBITION OF CHLAMYDIA-TRACHOMATIS GROWTH IN MOUSE FIBROBLASTS BY LIPOSOME-ENCAPSULATED TETRACYCLINE

The in-vitro susceptibility of Chlamydia trachomatis to liposome-encapsulated tetracycline was determined and compared with free tetracycline. Anionic, cationic and neutral small unilamellar liposomes were used in this study. Chlamydia-infected mouse fibroblast monolayers were continuously exposed to varying concentrations of antibiotic, incubated for 48 h and Giemsa stained. The minimum inhibitory concentration (MIC) for anionic, cationic and neutral liposomes containing tetracycline were 0·38, 0·08 and 0·04 mg/L, respectively. This was approximately 2, 10, and 20 times more efficient than free tetracyline (MIC, 0·79 mg/L). Neutral liposomes displayed no visible toxic side-effects on the host cells. When compared with free tetracycline, neutral liposomes were the most efficient for the delivery of inhibitory concentrations of tetracycline to chlamydia-infected mouse fibroblast L cell cultures. ©1992 The British Society for Antimicrobial Chemotherapy.