Preliminary studies on the effect of glutathione S-transferase from Providencia stuartii on the antimicrobial activity of different antibiotics.

Glutathione S-transferase has been isolated and purified from a Providencia stuartii CH 114 strain. The effect of the enzyme on the antimicrobial activity of amikacin, cefotaxime, cephalexin, ampicillin, nalidixic acid, and ofloxacin was tested. The efficiency of all antibiotics tested, except nalidixic acid and ofloxacin, is relevantly decreased by the presence of glutathione S-transferase in the medium culture, as proved by the increased value of MIC. The effect of glutathione S-transferase on the drugs is not significantly affected by the addition of exogenous glutathione. The possible mechanism of action of the enzyme is also discussed.