Reducing the risk of Chlamydia trachomatis genital tract infection by evaluating the prophylactic potential of vaginally applied chemicals

The need to provide women with a partner-independent method of prophylaxisagainst sexually transmitted disease (STD) agents, including Chlamydia trachomatis, has led to a directed effort to developa vaginallyapplied,broad-spectrumantimicrobialpreparation that isbothsafeand effective. Usinga murine modelof C. trachomatis lowergenital tract infection,we tested the abilityof various vaginallyapplied chemicalsto alter the course of infectionin femalemicechallengedwith infectious doses ranging from 103 to 1W inclusionforming units of an oculogenital serovar of C. trachomatis. When administered in a methylcelluloselpropylene glycol-based gel 15 minutes prior to challenge, four widely used topical antimicrobials (benzalkonium chloride, chlorhexidine, nonoxynol-9, and polymyxin B) wereshown to protect against infection.These results support the possibility that this type of interventional method may be a clinically relevant means of prophylaxis against sexually transmitted infection with C. trachomatis, the most common bacterial STD agent. More than 20 years ago, Dr. Balwant Singh and his col-leagues at the University of Pittsburgh proposed the use of antimicrobial vaginal preparations as both prophylaxis for and treatment of venereal diseases, on the basis of in vitro studie