Cysteine Hydropersulfide Inactivates β-Lactam Antibiotics with Formation of Ring-Opened Carbothioic S-Acids in Bacteria

Abstract

Hydrogen sulfide (H2S) formed during sulfur metabolism in bacteria has been implicated in the development of intrinsic resistance to antibacterial agents. Despite the conversion of H2S to hydropersulfides greatly enhancing the biochemical properties of H2S such as antioxidant activity, the effects of hydropersulfides on antibiotic resistance have remained unknown. In this work, we investigated the effects of H2S alone or together with cystine to form cysteine hydropersulfide (CysSSH) on the activities of antibacterial agents. By using the disc diffusion test, we found that CysSSH treatment effectively inactivated β-lactams of the penicillin class (penicillin G and ampicillin) and the carbapenem class (meropenem). These β-lactams were resistant to treatment with H2S alone or cystine alone. In contrast, cephalosporin class β-lactams (cefaclor and cefoperazone) and non-β-lactam antibiotics (tetracycline, kanamycin, erythromycin, and ofloxacin) were stable after CysSSH treatment. Chromatographic and mass spectrometric analyses revealed that CysSSH directly reacted with β-lactams to form β-lactam ring-opened carbothioic S-acids (BL-COSH). Furthermore, we demonstrated that certain bacteria (e.g., Escherichia coli and Staphylococcus aureus) efficiently decomposed β-lactam antibiotics to form BL-COSH, which were transported to the extracellular space. These data suggest that CysSSH-mediated β-lactam decomposition may contribute to intrinsic bacterial resistance to β-lactams. BL-COSH may become useful biomarkers for CysSSH-mediated β-lactam resistance and for investigation of potential antibacterial adjuvants that can enhance the antibacterial activity of β-lactams by reducing the hydropersulfides in bacteria.

Hydrogen Sulfide and Carbon Monoxide Tolerance in Bacteria

“…A new mode of antibiotic resistance mediated by sulfide was reported in pathogenic bacteria that involves inhibition of the oxidative stress imposed by ROS-generating antibiotics. Several studies described that the genes encoding H 2 S-releasing enzymes, such as CBS and CSE, in B. anthracis , P. aeruginosa , S. aureus , and M. tuberculosis, or 3-MST in E. coli , contribute to tolerance to gentamicin, ampicillin and nalidixic acid [ 31 , 33 ].…”

Chemical Biology of Reactive Sulfur Species: Hydrolysis-Driven Equilibrium of Polysulfides as a Determinant of Physiological Functions

“…Recent studies also suggested that reactive sulfur species can have potent anti-inflammatory activity in cells and in vivo ( 45 , 48 , 49 ). In bacteria, persulfides and polysulfides offer protection from external bactericidal insults caused by immune cell responses and antibiotics ( 29 , 36 ). Thus, bacteria-specific persulfide-producing machinery may become an attractive target for development of antibacterial drugs ( 29 , 36 ).…”

Metabolic and Structural Insights into Hydrogen Sulfide Mis-Regulation in Enterococcus faecalis

“…These cytoprotective properties attributed to H 2 S may well be the result of downstream, more oxidized sulfur species, collectively termed reactive sulfur species (RSS) [ 8 ]. One of these RSS is the organic persulfide (RSSH), which has enhanced nucleophilicity compared to its thiol counterpart and readily reacts with infection-relevant oxidants and β-lactam antibiotics [ 8 , 9 , 10 , 11 ]. Although much of the work on RSS has focused on mammalian systems [ 8 ], RSS biogenesis has been shown to be present in a number of bacteria [ 7 , 12 , 13 , 14 ].…”