MIAMI--A fat molecule found in human breast milk may someday be used to prevent the transmission of chlamydia and perhaps other sexually transmitted diseases. The findings, presented here today at the American Society for Microbiology's annual meeting, could lead to an antibiotic cream to combat a bug that each year leaves 25,000 American women infertile.
Drug companies are now testing chlamydia-killing proteins or mild detergents that could be added to spermicidal lubricants. But Charles Isaacs, a microbiologist at the New York State Institute for Basic Research in Staten Island, thought he might find candidate drugs among a poorly understand group of antibiotics: fat molecules in breast milk.
Isaacs isolated four lipids from breast milk that had some antibacterial properties in cell culture and sent them to chlamydia researcher Mary Lampe at the University of Washington, Seattle. Lampe and her colleagues mixed each lipid with infectious chlamydia, then added the mixture to mouse skin cells in culture. After 2 hours, the bacteria had successfully infected skin cells bathed in three of the lipids; however, one lipid--2-O-octyl-Sn-glycerol--blocked the infection entirely. Images of the stymied chlamydia indicated that the lipid had punched gaping holes in the microbe's inner membrane.
"This is an exciting antibacterial approach," says Elizabeth Wagar, a microbiologist who studies antichlamydia proteins at the University of California, Los Angeles, School of Medicine. According to Lampe, preliminary results suggest that 2-O-octyl-Sn-glycerol also inhibits gonorrhea infection, indicating that it could perhaps serve as a broader spectrum antibiotic. Lampe's group is now trying to develop a lipid-bearing cream that could be tested in animals.