(773) Utility of maternal cultures In laboring patients with isolated maternal fever or suspected intra-amniotic infection

There are no guidelines regarding the practice of taking cultures in laboring parturients with isolated intrapartum fever or suspected intra-amniotic infection. The objective of this study was to determine the utility of maternal cultures in febrile parturients and to examine risk factors for positive cultures.

Study Design: In this retrospective cohort study from 2005-2015, all parturients at term at a tertiary medical center with a fever of ≥ 38°C during a trial of labor of a singleton fetus were included. In our institution, urine, blood, and vaginal cultures are routinely taken in all laboring patients with isolated intrapartum fever or suspected intra-amniotic infection. Clinical and demographic data, including results of cultures and neonatal results, were collected by chart review.  Routine statistical tests were applied and multivariable logistic regression was performed to identify risk factors for positive cultures.

Results: There were 1813 febrile patients included, with a mean maximum fever of 38.2°C; of these 1734 (95.6%) had blood cultures taken, 1327 (73.2%) had vaginal cultures, and 1612 (88.9%) had urine cultures, and 288 had placental cultures. Of the blood cultures, 1653 (95.3%) were negative and 25 (1.4%) were likely contaminated; leaving 56 (3.2%) positive cultures. Of the vaginal cultures, 1158 (87.3%) were negative; the majority of the positive cultures were GBS. Of the urine cultures, 1442 (89.4%) were negative, and the majority of the positive cultures were either GBS, Klebsiella, or E. coli. Neonatal cultures were taken in 1668 (92%) of cases, of these, 1645 (98.7%), were negative. In multivariable analysis, patients with higher fever were more likely to have positive blood cultures aOR 2.9 (95%CI 1.7, 5.2).

Conclusion:

The yield of maternal blood cultures in labors complicated by fever is extremely low. The organisms identified in the 10.6% of positive urine cultures are treated by the empiric antibiotics started in cases of suspected chorioamnionitis. The practice of routinely collecting maternal cultures in all labors complicated by fever is not supported by evidence.