THE VAGINAL MICROFLORA OF PIG-TAILED MACAQUES AND THE EFFECTS OF CHLORHEXIDINE AND BENZALKONIUM ON THIS ECOSYSTEM

Background and Objectives: To characterize normal vaginal microflora o f pig-tailed macaques and to evaluate two commonly used intravaginal c ompounds, chlorhexidine (CHG), a vaginal antiseptic (Surgilube, E. Fou gera, Melville, NY), and benzalikonium chloride (BZK) (spermicidal con traceptive) in this monkey model to assess effects on the vaginal micr oflora. Study Desigrl: Vaginal swabs were collected for microbiologic analysis to characterize normal flora. Subsequently, the vagina was ex posed to either CHG or BZK twice at 24-hour intervals. Results: The va ginal microflora of 26 pig-tailed macaques was found to be remarkably similar to the vaginal flora of the human with respect to frequency of vaginal colonization by H2O2-producing lactobacilli, Prevotella speci es, and several other microorganisms. After two vaginal applications a t 24-hour intervals, CHG had only small effects on the vaginal microfl ora of five animals. By contrast, BZK applied by the same protocol had profound adverse effects on the lactobacilli and Peptostreptococcus a nd more transient effects on vaginal Prevotella and viridans streptoco cci of six animals. Conclusions: These observations demonstrate that t he vaginal microflora of the pig-tailed macaque is a useful model in w hich to further evaluate newly developed intravaginal contraceptives t hat may be microbicidal and/or virucidal before widespread intravagina l use in women.