Prenatal arsenic exposure and intestinal microbiota in Bangladeshi children

whole genome shotgun metagenomics Background: Arsenic has antimicrobial properties at high doses yet few studies have examined its effect on gut microbiota. This warrants investigation since arsenic exposure increases the risk for many diseases in which gut microbiota have been shown to play a role. Objective: To examine the role of arsenic exposure early in life on the composition of intestinal microbiota using a nested case-control study of children exposed to low and high arsenic exposure during development (N=50). Methods: Arsenic exposure was measured in maternal drinking water collected <16 weeks gestational age using inductively coupled plasma mass spectrometry. Composition of gut microbiota was evaluated using 16S rRNA gene sequence and shotgun sequencing was performed to evaluate the genomics content of gut microbiota. Results: The gut microbiota in the high arsenic exposure group had increased abundance in Proteobacteria compared to the low exposure group. Furthermore, we identified 332 bacterial genes that were enriched in the high arsenic exposure group and positively correlated with arsenic concentration in drinking water including genes that are involved in virulence and multidrug resistance. Furthermore, over 80% of these genes corresponded to Escherichia coli and Salmonella enterica suggesting that these species were enriched in the high arsenic exposure group. Conclusions: This study provides preliminary data indicating that arsenic exposure early in life was associated with altered gut microbiota in Bangladeshi children. Given the importance of gut microbiota to human health, further studies are needed to confirm this finding and determine the contribution of gut microbiome to arsenic-related diseases.