Effect of exposure to antibiotics on the gut microbiome and biochemical indexes of pregnant women

Abstract

Introduction: Exposure to antibiotics (ABX) during pregnancy can have a systematic effect on both fetal and maternal health. Although previous biomonitoring studies have indicated the effects on children of extensive exposure to ABX, studies on pregnant women remain scarce. To explore the effect on pregnant women of environmental exposure to ABX through accidental ingestion and identify potential health risks, the present study investigated 122 pregnant women in East China between 2019 and 2020.

Research design and methods: The presence of six categories of ABX (quinolones, sulfonamides, lincosamides, tetracyclines, amide alcohol ABX, and β-lactams) in plasma samples taken from the pregnant women was investigated using an ABX kit and a time-resolved fluorescence immunoassay.

Results: All six ABX were detected in the plasma, with a detection rate of 17.2%. It was discovered that the composition of intestinal flora in pregnant women exposed to ABX was different from that of pregnant women who had not been exposed to ABX. The intestinal flora of pregnant women exposed to ABX also changed at both the phylum and genus levels, and several genera almost disappeared. Furthermore, the metabolic levels of glucose and insulin and the alpha diversity of pregnant women exposed to ABX were higher than those of pregnant women not exposed to ABX.

Conclusion: Pregnant women are potentially at higher risk of adverse microbial effects. Glucose metabolism and insulin levels were generally higher in pregnant women exposed to ABX than in unexposed women. Also, the composition and color of the gut microbiome changed.

Keywords: antibodies; gastrointestinal tract; gynecology; nutritional sciences.

Figure 1

Richness and diversity of the gut microbiota in pregnant women who had been exposed to antibiotics (ABX) and those who had not. (A) Venn diagram of exposure to ABX in pregnant women; controls had not been exposed to ABX while detected ABX had. Detected ABX had more operational taxonomic units than controls. (B) Alpha diversity was calculated using QIIME2 V.2018.2 based on a sequence similarity level of 100%, including the Chao richness estimator, observed species, coverage, and the Shannon diversity index. Detected ABX showed higher alpha diversity than controls. Principal coordinates analysis based on the unweighted UniFrac matrix (C) and weighted UniFrac matrix (D) showed that the overall fecal microbiota composition was different between the two groups. Each point represents one sample of antibiotic exposure (red, controls, n=25; blue, detected ABX, n=12). The distances between different samples reflect the comparability of the two groups.

Figure 2

Composition of the gut microbiome at phylum and genera levels and several almost-disappeared genera in the second trimester. (A, B) The composition of the gut biome microflora of the two groups, indicating the dominant microflora. (C) The genera of Escherichia–Shigella, which are sensitive to sulfonamide antibiotics, almost disappeared in the gut microbiomes of pregnant women who had been exposed to antibiotics. (D) The phylum of Actinobacteria and (E) the genus of Barnesiella were sensitive to tetracycline antibiotics and declined or disappeared in pregnant women who had been exposed to antibiotics. (F) Ruminococcaceae UCG-014 was affected by both sulfonamides and tetracyclines and declined in women who had been exposed to antibiotics. ABX, antibiotics.