Distribution of antibiotic resistance genes in glacier environments

Abstract

Summary: Antibiotic resistance genes are biologically transmitted from microorganism to microorganism in particular micro‐environments where dense microbial communities are often exposed to an intensive use of antibiotics, such as intestinal microflora, and the soil microflora of agricultural fields. However, recent studies have detected antibiotic‐resistant bacteria and/or antibiotic resistance genes in the natural environment geographically isolated from such areas. Here we sought to examine the prevalence of antibiotic resistance genes in 54 snow and ice samples collected from the A rctic, A ntarctic, C entral A sia, N orth and S outh A merica and A frica, to evaluate the level of these genes in environments supposedly not affected by anthropogenic factors. We observed a widespread distribution of antibiotic resistance genes in samples from various glaciers in C entral A sia, N orth and S outh A merica, G reenland and A frica. In contrast, A ntarctic glaciers were virtually free from these genes. Antibiotic resistance genes, of both clinical (i.e. aac(3) , bla IMP ) and agricultural (i.e. strA and tetW ) origin, were detected. Our results show regional geographical distribution of antibiotic resistance genes, with the most plausible modes of transmission through airborne bacteria and migrating birds.