Investigation of Retrograde group B Streptococci infection and still-birth in Rat

Introduction and Objectives: Group B Streptococcus (GBS) still catches infants live in the world. Ascending GBS infection during pregnancy involves bacterial trafficking from the vagina, ultimately leading to bacterial invasion of placental membrane, the amniotic cavity, and the fetus. It causes different complications like stillbirth and neonatal mortality. So, GBS experimental infection of rats was done and investigated their complications. Materials and Methods: Up to 24 female Wistar Rats were mated and intra vaginally infected after pregnancy.The control group was received intra-vaginally 100 uL sterile normal saline and treatment group was inoculated with 100 uL of 108 CFU/ml of GBS( ATCC 13813) in the third week after mating.Five rats were mated and infected but had normal delivery. Before delivery (20th day) uteruses were removed and pups were cultured in Thioglycolate broth. Microbiological identification were confirmed by Beta hemolytic on sheep Blood agar, Gram staining. Catalase test and CAMP test.Results: In the control groups there were 89 pups vs. infected group had 51 pups. Culturing showed negative (100%, 89/89) for control groups and 48 pups (from 51) 94.11% had positive culture and GBS were recovered consequence. Two of five mothers that were infected and normally delivered, did not have any pups. One rat delivered 2 pups and another three ones. After removing uterus, four dead pups in uterus branch of one mother was observed. Two rats delivered dead pups after 20th days of mating.Conclusion: These effects showed that GBS is still one of the delivery defects that causes abortion and can causes to infect the amniotic sac and embryo in the form of retrograde that results to fetus death. and this study confirmed the Vornhagenʹs study in 2017. Also, in the infected group as control, it was observed that GBS causeS to both preterm delivery and fetus death.

کلیدواژه ها:

GBS ، Experimental Infection ، Retrograde ، Stillbirth