The effect of antibiotic therapy on intrauterine infection-induced preterm parturition in rabbits.
OBJECTIVE
The purpose of this study was to determine whether early antibiotic administration to pregnant rabbits with intrauterine infection could prevent preterm delivery and perinatal mortality.


METHODS
Under hysteroscopic guidance, pregnant rabbits at 70% gestation (21 days) were allocated to three groups: (1) control group, transcervical inoculation of 0.2 ml phosphate-buffered saline (n = 16); (2) infection group, transcervical inoculation of 0.2 ml of 10(5) colony-forming units (CFU) of Escherichia coli (n = 21); (3) infection and antibiotics group, transcervical inoculations of 0.2 ml of 10(5) CFU of E. coli and ampicillin-sulbactam 150 mg/kg every 8 h intramuscularly (n = 32). To examine the consequences of treatment delay, animals in the latter group were subdivided to receive antibiotics at different time intervals of 0, 6, 11 and 18 h after bacterial inoculation. The intervals from bacterial inoculation to delivery and litter survival were documented. Systemic (rectal) temperatures were recorded at 4 h intervals through the first 36 h and every 12 h until delivery. A p value of < 0.05 was considered significant.


RESULTS
All rabbits inoculated with E. coli without antibiotic treatment delivered prematurely. The median inoculation-to-delivery interval was significantly shorter in the infected group than in the control group (median 32 h, range 14.9-76.5 h vs. median 219 h, range 173-246 h, respectively; p < 0.0001). Antibiotic administration within 12 h of inoculation, but not after 18 h, increased duration of pregnancy (by reducing the rate of preterm delivery) and neonatal survival (0% vs. 71%; p < 0.0001). The mean temperatures at delivery of animals whose treatments began at 6 and 11 h post-inoculation were significantly lower than those untreated with antibiotics or those treated at 18 h post-inoculation (p < 0.0001 for each comparison).


CONCLUSIONS
Antibiotic administration can prolong pregnancy and reduce perinatal mortality if administered early (within 12 h of microbial inoculation) in a rabbit model of ascending intrauterine infection.
Fidel
P
P
Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences, New Orleans, Louisiana, USA.
Ghezzi
F
F
Romero
R
R
Chaiworapongsa
T
T
Espinoza
J
J
Cutright
J
J
Wolf
N
N
Gomez
R
R
D000667:Ampicillin / Q000008:administration & dosage*; D000818:Animals; D001831:Body Temperature; D004195:Disease Models, Animal; D004359:Drug Therapy, Combination / Q000008:administration & dosage*; D004927:Escherichia coli Infections / Q000517:prevention & control*; D005260:Female; D005322:Premature Rupture of Fetal Membranes / Q000517:prevention & control*; D007273:Injections, Intramuscular; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000517:prevention & control*; D011817:Rabbits; D011897:Random Allocation; D013407:Sulbactam / Q000008:administration & dosage*
C035444:sultamicillin; D000667:Ampicillin; D013407:Sulbactam