EFFECTS OF NONOXYNOL-9 ON VAGINAL MICROFLORA AND CHLAMYDIAL INFECTIONIN A MONKEY MODEL

Background and Objectives: Nonoxynol-9, an intravaginal microbicide, i s chlamydiacidal in vitro but also cytotoxic. This study examines the effects of nonoxynol-9 in vivo, using a pigtail macaque model of chlam ydial cervicitis. Goals: To establish a minimum infectious dose of Chl amydia trachomatis in the macaque, and to observe the effects of a sin gle dose of nonoxynol-9 on efficiency of chlamydial infection, vaginal microflora, and cervicovaginal irritation. Study Design The effects o f 4% nonoxynol-9, C. trachomatis (5,000 or 10,000 IFU) or both nonoxyn ol-9 application and chlamydial infection were studied in 17 macaques. Results: Following a single application of nonoxynol-9, chlamydial in fection was prevented in 4 of 6 monkeys infected with 10,000 IFU; ther e was a transient decrease in anaerobic gram-negative rods (P < 0.05) and Peptostreptococci (P > 0.05), but no change in Lactobacillus. Mild cervicovaginal irritation was observed in the monkeys. Conclusions: A single dose of nonoxynol-9 causes minimal vaginal flora and epithelia l irritation, and may be useful for prevention of chlamydial infection .