Antibiotic perturbation of the murine gut microbiome introduces inter-individual susceptibility to arsenic.

Arsenic is a Group 1 human carcinogen and at least 200 million people around the world are exposed to unsafe levels of arsenic, predominantly through contaminated drinking water. Arsenic has also been used for hundreds, if not thousands, of years as an intentional poison due to its odorless/tasteless properties and the general lack of technology required to identify it. Both acute and chronic arsenic-related health outcomes are highly variable among similarly exposed individuals even after controlling for important factors, like host genetics, making the mechanisms underlying this often-made epidemiologic observation difficult to experimentally address and not fully understood. Here, we describe an experimental model of arsenic exposure in C57BL/6 mice that recapitulates key aspects of inter-individuality in disease observed in humans. We show that co-administration of the antibiotic, cefoperazone, and high-level arsenic (100 ppm, inorganic sodium arsenate) results in incomplete mortality with a ratio of 60 % lethality to 40 % survival, and that survival, at least in part, depends not only on an intact microbiome but also a regulated response involved with water transport. This work provides an experimental framework for identifying critical pathways involved in generating inter-individual variability in disease outcome following arsenic exposure.