KILLING OF CHLAMYDIA-TRACHOMATIS BY NOVEL ANTIMICROBIAL LIPIDS ADAPTED FROM COMPOUNDS IN HUMAN BREAST-MILK

The development of new methods for prevention of sexually transmitted Chlamydia trachomatis infection is a top public health priority. Topic al self-administered vaginal microbicides represent one such approach in which the organism is eradicated at the time of initial exposure. T o this end, we examined the activity of five synthetic lipids adapted from naturally occurring compounds found in human breast milk. C. trac homatis serovar D or F elementary bodies were added to serial dilution s of the lipids and incubated for various times. Aliquots were then cu ltured in monolayers of McCoy cells, and inclusions were counted. A 7. 5 mM concentration of 2-O-octyl-sn-glycerol completely prevented growt h of C. trachomatis after 120 min of contact with the organism. The re maining lipids, 1-O-octyl-, 1-O-heptyl-, 2-O-hexyl-, and 1-O-hexyl-sn- glycerol, showed less activity, On electron microscopic examination, t he lipids were shown to have disrupted the chlamydial inner membrane, allowing leakage of the cytoplasmic contents from the cell. Lipid acti vity was unaffected by the presence of 10% human blood or alterations in pH from 4.0 to 8.0, conditions reflecting those sometimes found in the vagina. Our results suggest that these lipids, especially 2-O-octy l-sn-glycerol, may be effective as topical microbicides in preventing the transmission of C. trachomatis. Further efficacy and toxicity stud ies with these lipids and assessment of their activity against other s exually transmitted disease pathogens are in progress.