Will a Non-antibiotic Metalloid Enhance the Spread of Antibiotic Resistance Genes: The Selenate Story

Abstract

The rapid emergence of antibiotic resistance genes (ARGs) has become an increasingly serious threat to public health. Previous studies illustrate the antibiotic-like effect of many substances. However, whether and how commonly used or existing non-antibiotic metalloids (e.g., selenate) would enhance ARG spread remains poorly known. Here, we tracked the long-term operation of a bioreactor continuously fed with selenate for more than 1000 days. Metagenomic sequencing identified 191 different ARGs, of which the total abundance increased significantly after the amendment of selenate. Network analyses showed that ARGs resisting multiple drugs had very similar co-occurrence patterns, implying a potentially larger health risk. Host classification not only indicated multidrug-resistant species but also distinguished the mechanism of ARG enrichment for vertical transfer and horizontal gene transfer. Genome reconstruction of an ARG host suggested that selenate and its bioreduction product selenite could stimulate the overproduction of intracellular reactive oxygen species, which was confirmed by the direct measurement. Bacterial membrane permeability, type IV pilus formation, and DNA repair and recombination were also enhanced, together facilitating the horizontal acquirement of ARGs. Overall, this study for the first time highlights the ARG emergence and dissemination induced by a non-antibiotic metalloid and identifies ARG as a factor to consider in selenate bioremediation.

Mobile Antimicrobial Resistance Genes in Probiotics

“…Moreover, as ARGs were found in the vast majority of the samples tested, not a negligible proportion of them, it is possible that the presence of ARGs in bacteria may also play a role in their probiotic effect. ARGs play a role in defence against antibiotics and may provide general fitness against specific toxic effects for bacteria [ 98 , 99 ]. One may make an analogy with earlier practice.…”

Mobile antimicrobial resistance genes in probiotics

“…ARGs play a role in defence against antibiotics and may provide general fitness against specific toxic effects for bacteria. 81,82 One may make an analogy with earlier practice. In livestock farming, antibiotics have been widely used as feed supplements for yield enhancement on a purely empirical basis.…”

A mixed blessing of viruses in wastewater treatment plants

“…To identify ARGs, gene sequences predicted from viral genomes were searched against the Comprehensive Antibiotic Resistance Database (CARD, v3.1.1) using DIAMOND v0.9.25.126 [112][113][114] , with e-value ≤10 -5 and identity ≥50%. Predicted viral ARGs were compared to their host MAGs to find a sequence homology, using BLASTn with nucleotide identity ≥70% and sequence coverage ≥80%.…”