The Effect of Hydrogen Sulfide and Reactive Sulfur Species on Bacterial Virulence and Antibiotic Sensitivity

Recent research has demonstrated the important role of hydrogen sulfide (H2S) and its derivatives, reactive sulfur species (RSS), as modulators of various redox-regulated physiological processes in bacteria. Bacterial cells are equipped with enzymes that synthesize and catabolize H2S and RSS, and sensors that control the expression of genes whose products ensure the maintenance of safe levels of these compounds in cells and the survival of bacteria in the host environment. With the rapid growth of resistant pathogens, the impact of H2S and RSS on bacterial virulence and antibiotic sensitivity is attracting increasing attention. The possibility of enhancing the efficacy of widely used antibiotics by artificially modulating H2S levels is being explored. This review summarizes current data on the sources and conditions of endogenous H2S and RSS production, the molecular mechanisms of action of various concentrations of exogenous and endogenous H2S, and the regulatory factors that control the expression of virulence and antibiotic resistance genes. Possible reasons for the conflicting results obtained by different research groups regarding the possibility of modulating bacterial sensitivity to antibiotics by altering the production of endogenous H2S are discussed.