The roles of hydrogen sulfide and reactive sulfur species in bacterial life within the human body

We summarize current knowledge on the roles of hydrogen sulfide (H 2 S) and reactive sulfur species (RSS) in bacterial strategies for survival and colonizing within the human body. Bacteria inhabiting the human body utilize H 2 S, derived from their host environment, as an electron donor or signaling molecule, while others generate and directly use H 2 S through the metabolism of sulfur-containing organic and inorganic compounds. The intracellular levels of H 2 S and RSS are tightly controlled by various mechanisms, enabling bacteria to acquire antibiotic resistance and obtain iron from their hosts. These processes are driven by transcription factors that specifically sense RSS, some of which are derived from H 2 S. The polysulfidation of specific cysteine residues in these transcription factors plays a key role in regulating the expression of related genes, thereby governing the interactions between bacteria and their hosts. The synthesis of H 2 S and RSS by bacteria not only affects their pathogenicity but can also influence overall health of the human host.