토끼에서 자궁경을 통한 대장균의 자궁내 주입으로 상행성 감염과 유사한 상황을 만들고 이에 따른 조산 발생 여부를 확인하고, 주입 균주에 민감한 항생제의 사용으로 이러한 감염이 어느정도 극복될 수 있는 지를 알아보고자 시도한 본 실험 결과 다음과 같은 결론을 얻었다. 대장균만을 투여한 군에서는 모두 조산이 일어났으며 생리식염수를 투여한 대조군에서는 한마리도 조산을 하지 않아 유의한 차이를 보였다. 항생제의 투여를 일찍 시작함에 따라 조산의 빈도도 유의하게 감소하는 경향을 보였으며 주산기 태아 예후를 증진시켰으며, 양수 배양검사 결과, 탈락막 배양검사 결과 및 조직학적 융모양막염의 발생도 마찬가지로 감소하는 경향을 보였다. 따라서 본 실험 결과 세균에 의하여 조산이 유발됨을 확인할 수 있었고, 이러한 세균에 의한 조산에서 항생제의 효과도 확인할 수 있었다.

Bacterial infection has been implicated in premature labor in human. But it is impossible to undergo human study of bacteria-induced preterm delivery. If we carry out animal experiment which simulate human preterm delivery induced by bacteria, studies for mechanism, diagnosis, and treatment of preterm delivery will be progressed rapidly. To elucidate mechanisms and potential intervention strategies in preterm pregnancy loss, we observed bacteria-induced preterm labor and the protecting effect of administration of antibiotics with hysteroscopy-guided intracervical inoculation of Escherichia coli. Sterile saline solution(group I, n=5) or 2x107cfu (colony-forming units) of E. coli bilaterally in the cervix of pregnant New Zealand White rabbits on day 20 or 21(70% of gestation) by hysteroscopy was inoculated and rabbits were assinged to ampicillin-sulbactam therapy beginning at 0hr(group II, n=4), 2 hr(group III, n=4), 4 hr(group IV, n=2), and 16 hr(group V, n=2) after inoculation with E. coli, or to no antibiotic therapy(group VI, n=3). Unasyn(ampicillin-sulbactam) was used and its daily dosage was 100 mg/kg/day. The occurrence of vaginal bleeding or preterm birth was observed every two hours. If one rabbit fetus was found to be delivered, exploratory laparotomy was done. Amniotic fluid culture on each sac, decidual culture on each uterine cavity, and pathologic examinations on each placenta were done. The results of experiments are as follows. In control group(0.2cc sterile saline inoculation only), there was no preterm labor and no bacterial growth in culture. In all three rabbits in group VI, preterm delivery occurred and the culture results were all positive in maternal blood, decidua, and amniotic sacs. Preterm delivery also occurred in group V, but results of maternal blood culture were all negative. Increased trend in the occurrence of preterm delivery was statistically significant in the order(p<0.05) : group I(0/5), group II(0/4), group III(0/4), group IV(0/2), group V(2/2), and group VI(3/3). Pregnancy outcomes on the basis of the number of living fetus, dead fetus, and macerated fetus, have significant trend in the above order. Amniotic fluid culture results also had significant relationship(p<0.05) : group I(0.20), group II(20/26), group III(18/30), group IV(10/11), and group VI(7/7). In group V, amniotic fluid fail to be obtained due to severe oligohydramnios. Decidual culture results also had an increased trend; group I(0/32), group II(21/29), group III(20/30), gorup IV(16/16), gorup V(11/11), and group VI(25/25). It is statistically significant(p<0.05) Incidence of histologic chorioamnionitis was also significantly increased from group I to VI. These results indicate that E. coli inoculation has induced preterm delivery and antibiotic therapy has somewhat prevented preterm birth , amniotic fluid infection , decidual infection, and histologic chorioamnionits. Antibiotic effects were attenuated in cases of delayed antibiotic administration.