Perinatal factors can shape fecal microbiome patterns among pregnant women and their infants. However, there is scarce information about the effect of maternal demographics and perinatal exposures on antibiotic resistance genes (ARG) and mobile genetic element (MGE) patterns in pregnant women and infants. We examined fecal samples from pregnant women during their third trimester of pregnancy (n = 51) and 6-month-old infants (n = 40). Of the 91 participants, 72 represented 36 maternal-infant dyads, 15 were additional pregnant women, and 4 were additional infants. We assessed the effects of demographics, pre-pregnancy BMI, smoking and parity in the pregnancy resistome and the effects of demographics, delivery mode, feeding habits and prenatal antibiotic treatment on the infancy resistome. ARG and MGE richness and abundance were assessed using a SmartChip qPCR-array. Alpha diversity (Shannon and Inverse Simpson index) and beta diversity (Sorensen and Bray-Curtis index) were calculated. The Wilcoxon and the Kruskal non-parametric test were used for comparisons. There is a high variability in shared resistome patterns between pregnant women and their infants. An average of 29% of ARG and 24% of MGE were shared within dyads. Infants had significantly greater abundance and higher diversity of ARG and MGE compared to pregnant women. Pregnancy and infancy samples differed in ARG and MGE gene composition and structure. Composition of the fecal resistome was significantly associated with race in pregnant women, with non-white women having different patterns than white women, and, in infants, with extent of solid food consumption. Our data showed that the pregnancy and infancy resistome had different structure and composition patterns, with maternal race and infant solid food consumption as possible contributors to ARG. By characterizing resistome patterns, our results can inform the mechanism of antibiotic resistome development in pregnant women and their infants.

Overuse of antibiotics causing antibiotic resistance, an increase in Clostridium difficile infections, and increased adverse drug reactions is a growing problem. To combat this growing threat, the Centers for Disease Control started a program to improve the appropriate use of antimicrobials that focuses on antimicrobial stewardship. In the neonatal intensive care unit (NICU) medically fragile infants are commonly exposed to antibiotics resulting in a growing interest in applying antimicrobial stewardship principles in this patient population. The lack of treatment guidelines and the relatively narrow spectrum of individual antibiotics used to make the NICU a unique environment requiring a specialized approach to antimicrobial stewardship. This article examines the current antibiotic treatment data for common NICU illnesses including early and late-onset sepsis, pneumonia, and necrotizing enterocolitis, then reviews current recommendations for antimicrobial stewardship.

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