Distribution of Arsenic Resistance Genes in Prokaryotes

Abstract

Arsenic is a metalloid that occurs naturally in aquatic and terrestrial environments. The high toxicity of arsenic derivatives converts this element in a serious problem of public health worldwide. There is a global arsenic geocycle in which microbes play a relevant role. Ancient exposure to arsenic derivatives, both inorganic and organic, has represented a selective pressure for microbes to evolve or acquire diverse arsenic resistance genetic systems. In addition, arsenic compounds appear to have been used as a toxin in chemical warfare for a long time selecting for an extended range of arsenic resistance determinants. Arsenic resistance strategies rely mainly on membrane transport pathways that extrude the toxic compounds from the cell cytoplasm. The ars operons, first discovered in bacterial R-factors almost 50 years ago, are the most common microbial arsenic resistance systems. Numerous ars operons, with a variety of genes and different combinations of them, populate the prokaryotic genomes, including their accessory plasmids, transposons, and genomic islands. Besides these canonical, widespread ars gene clusters, which confer resistance to the inorganic forms of arsenic, additional genes have been discovered recently, which broadens the spectrum of arsenic tolerance by detoxifying organic arsenic derivatives often used as toxins. This review summarizes the presence, distribution, organization, and redundance of arsenic resistance genes in prokaryotes.

Co‐occurrence of antibiotic, biocide, and heavy metal resistance genes in bacteria from metal and radionuclide contaminated soils at the Savannah River Site

“…The zinc resistance gene zraR / hydH was the most abundant MRG subtype, and this along with copper resistance genes have been reported in the literature as being strong contributors to resistance traits, having direct correlations with as β‐lactamases, sulphonamides, macrolide‐lincosamide‐streptogramin and tetracycline resistance genes (Knapp et al , 2017). Arsenic associated resistance genes such as those in the ars gene clusters have been shown to be globally distributed and are suggested to have prominent roles in global arsenic biogeochemistry (Ben Fekih et al , 2018; Dunivin et al , 2019; Firrincieli et al , 2019). Iron and nickel resistance genes have also been shown to be significantly associated with ARGs such as multidrug, β‐lactamases, sulphonamides, macrolide‐lincosamide‐streptogramin, tetracycline, aminoglycosides and vancomycin resistance genes (Guo et al , 2014; Hu et al , 2017).…”

Transporters and Efflux Pumps Are the Main Mechanisms Involved in Staphylococcus epidermidis Adaptation and Tolerance to Didecyldimethylammonium Chloride

“…An important efflux system for the arsenic efflux pump (SE0334) showed an increase in 11.8-fold (Table 2). This efflux pump actively exports toxic arsenic compounds from cells [53]. The arsenic efflux system has multidrug-resistance members [54], and according to these data, we suggest that this system contributes to the active export of DDAC in SE11Ad, although further supporting evidence is needed.…”

“…Another multidrug efflux pump that was up−regulated was the arsenic efflux pump (arsB [SE0135], 5.97−fold). This energy−dependent efflux system belongs to the multi−drug−resistance protein family, which is involved in the active export of toxic compounds from cells [53,54].…”

“…In SE11Ad, SE0334 was up−regulated 11.8−fold, and in SE18To, arsB was up−regulated 6.0−fold ( Supplementary Table S2). There are many different arsenic efflux systems in cell membranes, and the ars operon is the most studied and known of these, although other novel arsenic efflux pumps have also been described [53]. Usually, these are considered as multidrug−resistance members of efflux systems [54].…”

A Novel Arsenate-Resistant Determinant Associated with ICEpMERPH, a Member of the SXT/R391 Group of Mobile Genetic Elements

“…The next putative gene codes for an Acr3-like protein. Acr3 is an arsenite efflux pump, which can pump inorganic arsenite from cells and is found in bacteria, archaea, fungi, and some plant species [86,87]. The final gene in this hotspot codes for a putative ArsR family transcriptional regulator.…”