1141 - Composition of Placental Cultures and Correlation with Maternal and Infant Blood Cultures in Mothers with Suspected Chorioamnionitis

Background: Placental culture is often used in combination with placental pathology in pregnant women with suspected chorioamnionitis.  While multiple studies have looked at the correlation of placental cultures with neonatal outcomes, few have looked at the composition of placental cultures in terms of the number of organisms and their identification. Our study aims to describe such characteristics of placental cultures and to compare organisms found in placental cultures with those in maternal and infant blood cultures.

Methods: We performed retrospective chart reviews on mothers and infants for whom a placental pathology and culture was sent at Loyola University Medical Center between January 2017 and December 2019.  We separated the mothers based the results of their placental cultures and pathologies and on the number of organisms found in each culture.  We then analyzed the identification of organisms of the positive cultures and compared these organisms with positive infant and maternal blood cultures.

Results: A total of 208 placental cultures out of 279 sent (73.84%) were positive. 63 (30.29%) positive cultures were monomicrobial, while 145 (69.71%) cultures were polymicrobial.  The most prevalent organisms found in all placental cultures were coagulase negative staphylococcus (26.44%), Streptococcus anginosus (16.83%), Corynebacterium species (14.90%), Lactobacillus species (14.90%), and Gardnerella vaginalis (13.94%).  A small fraction of positive placental cultures was associated with positive infant and maternal blood cultures (4.33% and 3.85%, respectively). When comparing the organisms in placental cultures with those in maternal and infant blood cultures, 100% and 71% (respectively) of cases with both positive blood and placental cultures had shared organisms.Distribution of most common organisms found in monomicrobial and polymicrobial placental cultures.
Distribution of placental cultures based on number of organisms.
Correlation of placental cultures with infant and maternal blood cultures.


Conclusion: The data collected from this study helps provide a biological profile of organisms found in placental culture for patients with suspected chorioamnionitis. Additionally, the data suggests that the organisms found in these cultures are often consistent with those found in maternal and infant blood cultures. The overall incidence of positive infant and maternal blood cultures is low as compared to positive placental cultures.