title: Failure of Chlamydia trachomatis to pass transplacentally to fetuses of TO mice infected during pregnancy.
abstract: Mice (strain TO) were inoculated with a human strain of Chlamydia trachomatis (serovar E) either 14 days before the detection of a vaginal plug (day 1 of pregnancy), or from one to nine days thereafter. The organisms were given via the intraperitoneal route (ip) or intravenously with an additional intravaginal inoculum (iv + ivag). Mice were killed on day 18 of pregnancy and the contents of the uterus examined. Chlamydiae were isolated from at least one placental disk of about a quarter of the mice. Organisms given via the ip route established placental colonisation more effectively. Thus, placental colonisation was detected in five of 16 mice given chlamydiae by the ip route (in six of eight placentas in one mouse), whereas colonisation occurred in only a single placenta from one of nine mice infected via the iv + ivag routes. Chlamydiae were isolated from 13 (6.25%) of 208 placentas examined; the degree of colonisation was variable and the individual placentas were colonised independently. Chlamydiae were not recovered from fetal tissue, even when there was heavy placental colonisation. Nor were they isolated from maternal spleens, even though there was antibody to C. trachomatis in all maternal sera; the titres were in the range 4-2048, depending on the time of chlamydial challenge. These experiments show that C. trachomatis did not cross the placenta and that the pregnancy outcome in these mice was not affected.
mesh_terms: D000818:Animals; D002690:Chlamydia Infections / Q000382:microbiology / Q000635:transmission*; D002692:Chlamydia trachomatis / Q000254:growth & development* / Q000302:isolation & purification; D004195:Disease Models, Animal; D005260:Female; D005333:Fetus / Q000382:microbiology*; D008431:Maternal-Fetal Exchange; D051379:Mice; D010920:Placenta / Q000382:microbiology*; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000382:microbiology*; D013047:Specific Pathogen-Free Organisms