Ascending group B streptococcal genital infection in the rabbit model.
OBJECTIVE
We investigated in a pregnant rabbit model the effects of intravaginal inoculation of type la group B streptococci and antibiotic intervention.


METHODS
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.


RESULTS
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.


CONCLUSIONS
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.
McDuffie
R S
RS
Department of Obstetrics and Gynecology, Kaiser Permanente and University of Colorado School of Medicine, Denver, USA.
Gibbs
R S
RS
D000667:Ampicillin / Q000627:therapeutic use; D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D004195:Disease Models, Animal; D004359:Drug Therapy, Combination / Q000627:therapeutic use; D005260:Female; D005831:Genital Diseases, Female / Q000188:drug therapy; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000188:drug therapy; D011256:Pregnancy Outcome; D011817:Rabbits; D013290:Streptococcal Infections / Q000188:drug therapy; D013292:Streptococcus agalactiae; D013407:Sulbactam / Q000627:therapeutic use
D000900:Anti-Bacterial Agents; D000667:Ampicillin; D013407:Sulbactam