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Background: A topical microbicide should protect against acquisition of sexually transmitted infection during both vaginal and rectal intercourse. The rectal microflora of the Macaca nemestrina (pig-tailed macaque) and humans were examined, as well as the histopathology of rectal tissues. In a subset of macaques, a human rectal isolate of Chlamydia trachomatis was inoculated into the rectum to establish rectal chlamydial infection.Goal: To evaluate the comparability of the pig-tailed macaque rectal model with humans.Study Design: Rectal swabs were collected for microbiologic analysis to characterize normal microflora in pig-tailed macaques and humans. Subsequently, 10 macaques received a rectal inoculation with C trachomatis, serovar D, prepared from a clinical rectal isolate.Results: The rectal microflora of pig-tailed macaques (n = 80) were found to be comparable with the rectal flora of humans (n = 40). The prevalence of Lactobacillus in the rectum was higher in the macaques than in humans. Coliform and Enterococcus were decreased in the macaques, as compared with those of humans. In 9 of 10 macaques, rectal chlamydial infection was confirmed by culture or ligase chain reaction on days 2, 7, and 14 after inoculation. The test results were positive for rectal chlamydial infection by ligase chain reaction only for the remaining animal on day 14 after inoculation.Conclusions: The findings demonstrate that the rectal environment of the pig-tailed macaque is a useful model for further evaluation of newly developed topical microbicides for rectal use. Furthermore, such products can be evaluated for protection against rectal chlamydial infection in this model. [ABSTRACT FROM AUTHOR]

Background and Objectives: Nonoxynol-9, an intravaginal microbicide, is chlamydiacidal in vitro but also cytotoxic. This study examines the effects of nonoxynol-9 in vivo, using a pigtail macaque model of chlamydial cervicitis., Goals: To establish a minimum infectious dose of Chlamydia trachomatis in the macaque, and to observe the effects of a single dose of nonoxynol-9 on efficiency of chlamydial infection, vaginal microflora, and cervicovaginal irritation., Study Design: The effects of 4% nonoxynol-9, C. trachomatis (5,000 or 10,000 IFU) or both nonoxynol-9 application and chlamydial infection were studied in 17 macaques., Results: Following a single application of nonoxynol-9, chlamydial infection was prevented in 4 of 6 monkeys infected with 10,000 IFU; there 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 epithelial irritation, and may be useful for prevention of chlamydial infection.

Background and Objectives: Although it has been hypothesized that repeated infections with Chlamydia trachomatis result in an increased potential for the development of infertility, it is not know whether repeated chlamydial infection by the vaginal route will result in an increased incidence of upper tract pathology or enhanced pathology., Goal of This Study: To determine whether guinea pigs given two infections with the chlamydial agent of guinea pig inclusion conjunctivitis would experience an increased incidence of pathologic changes compared with animals having only a single infection., Study Design: Guinea pigs previously infected with guinea pig inclusion conjunctivitis were challenged with a fresh intravaginal inoculum 73-77 days after the primary infection. Oviducts were examined either nine or 30 to 37 days after the challenge infection for pathologic changes and compared with control unchallenged animals 75 to 85 days after a primary infection., Results: A significant increase in the number of animals with oviducts demonstrating marked tubal dilatation was observed in the challenged animals 30 to 37 days after the challenge infection. There was no association of increased antibody titer and chlamydial Hsp60 with the presence of tubal dilatation., Conclusion: These data strongly indicate that repeated infection via the natural vaginal route does increase the risk of tubal damage.

Background and Objectives: The role of spermatozoa in carrying microorganisms from the cervix to the fallopian tubes and promoting infection was examined in eight pig-tailed macaques., Goal of This Study: The aim of this study was to determine whether spermatozoa play a role in the transport of Chlamydia trachomatis into the upper reproductive tract and in the pathogenesis of chlamydial salpingitis., Study Design: Five monkeys were inoculated with Chlamydia trachomatis in the cervix and mated, and three other monkeys were infected in the cervix but not mated., Results: Culture positive results were obtained for cervical samples from all animals. After cervical inoculation, no mated animals and one unmated animal had positive culture results for samples from the fallopian tubes. After mating, no spermatozoa examined in samples taken from the upper tract or cul de sac had elementary bodies (EBs) on their surfaces, and only one sample obtained from the cervix showed C. trachomatis attached to the spermatozoa, as determined by fluorescent antibody (FA) staining. Two of the mated monkeys became pregnant; one spontaneously aborted late in gestation, and the other delivered a normal female infant. The fallopian tubes of all eight monkeys were challenged directly with serovar D and examined for evidence of salpingitis. Repeat laparoscopy was performed to monitor the inflammatory response. Tubal specimens for isolation and polymerase chain reaction (PCR) were obtained. Hysterectomies were performed between 3 and 4 weeks after tubal inoculation. Histopathologic examination of the fallopian tubes revealed widespread inflammation consisting of focal collections of lymphocytes and plasma cells in the submucosa. Peritubal adhesions were observed in four of five mated monkeys and in two of three unmated monkeys., Conclusion: This study failed to confirm that spermatozoa play a role in the pathogenesis of C. trachomatis infection.