Free Sh Groups in Microbial Response to Antibiotics

Glutathione (GSH) is the primary molecule responsible for maintaining homeostasis. It is a tripeptide made up of cysteine, glutamate, and glycine. The primary function in redox homeostasis is carried out by the unbound sulfhydryl (SH) group from glutathione (GSH). Microorganisms have swift responses to alterations in their environment, and the use of antibiotics can stimulate the development of bacterial resistance. Transcription factors such as SoxRS, OxyR, NFκB, AP-1, Nrf-2, and P53 are sensitive to variations in the redox state of cells, which is influenced by redox-reactive groups like thiols. Our study monitored alterations in the levels of free sulfhydryl (-SH) groups in E. coli and S. aureus following their exposure to streptomycin and amoxicillin. An observation was made that streptomycin reduces the concentration of free sulfhydryl (SH) groups in both E. coli and S. aureus. Conversely, amoxicillin enhances the concentration of free SH groups in E. coli, but further reduces the concentration of these groups in S. aureus. There is a significant difference between Gram-positive and Gram-negative bacteria in this regard. These findings improve comprehension of the function of -SH groups in rectifying redox state imbalance in bacteria induced by antibiotics.