McDuffie R S, Gibbs R S
Department of Obstetrics and Gynecology, Kaiser Permanente and University of Colorado School of Medicine, Denver, USA.
Am J Obstet Gynecol. 1996 Aug;175(2):402-5. doi: 10.1016/s0002-9378(96)70153-9.
We investigated in a pregnant rabbit model the effects of intravaginal inoculation of type la group B streptococci and antibiotic intervention.
We inoculated 10(4) to 10(6) cfu of type la group B streptococci into the upper vagina hysteroscopically at day 21 to 27 of a 31-day gestation. Initially we studied the natural history in 23 animals and then allocated the next 31 animals to receive either no therapy or ampicillin-sulbactam intramuscularly beginning immediately after inoculation. Outcomes were delivery, fever, positive cultures for group B streptococci, any live fetuses, and maternal death.
Without antibiotic treatment upper vaginal inoculation led to frequent complications, namely, fever in 44% (15/34), delivery in 41% (14/34), positive endometrial cultures in 47% (15/32), and positive blood cultures in 26% (7/27). Live fetuses were present in only 53% (18/34). Animals treated with antibiotics were significantly less likely to have fever (p < 0.01), positive endometrial cultures (p < 0.01), or positive blood cultures (p = 0.03) and were more likely to have a live fetus (p = 0.04) than untreated animals were.
Upper vaginal inoculation with type la group B streptococci in the rabbit led to an ascending infection of the upper genital tract, causing serious adverse outcomes in 40% with bacteremia in 26%. Early antibiotic intervention significantly improved outcomes. The susceptibility of the rabbit to ascending perinatal group B streptococci infection makes it an appealing model for further work pertinent to human disease.
我们在孕兔模型中研究了经阴道接种B族链球菌1a型及抗生素干预的效果。
在妊娠31天中的第21至27天，通过宫腔镜将10⁴至10⁶cfu的B族链球菌1a型接种到阴道上段。最初我们研究了23只动物的自然病程，然后将接下来的31只动物分为两组，一组不接受治疗，另一组在接种后立即肌肉注射氨苄西林-舒巴坦。观察指标包括分娩、发热、B族链球菌培养阳性、存活胎儿数量及母体死亡情况。
未经抗生素治疗时，阴道上段接种导致频繁出现并发症，即44%（15/34）发热、41%（14/34）分娩、47%（15/32）子宫内膜培养阳性、26%（7/27）血培养阳性。仅53%（18/34）有存活胎儿。与未治疗动物相比，接受抗生素治疗的动物发热（p<0.01）、子宫内膜培养阳性（p<0.01）或血培养阳性（p = 0.03）的可能性显著降低，且有存活胎儿的可能性更大（p = 0.04）。
兔经阴道接种B族链球菌1a型可导致上生殖道上行感染，40%出现严重不良结局，26%发生菌血症。早期抗生素干预显著改善了结局。兔对围产期B族链球菌上行感染的易感性使其成为进一步研究人类疾病相关工作的有吸引力的模型。
