Aims: To study the effect of diethylsulphoxide (DESO) on Escherichia coli growth, survival and ionic exchange in comparison with dimethylsulphoxide (DMSO).

Methods and Results: Bacterial survival was estimated by counting colony-forming units and by the most probable number (five-tube) technique; the K+ and H+ transport and H2 formation were determined electrochemically. Diethylsulphoxide at concentrations between 0·01 and 0·5% (w/v) stimulated and above 5% decreased the anaerobic growth rate and survival. 2H: K+ exchange and H2 formation were lost at 5% DESO. At 0·05% DESO the kinetic characteristics of H: K+ exchange and H2 formation were typical for ΔμH+-dependent TrkA uncoupled with F0F1 under respiration.

Conclusions: Diethylsulphoxide at low concentrations serves as an electron acceptor for an anaerobic respiratory chain stimulating bacterial growth and survival through the modulation of H+ : K+ exchange and H2 formation activity. The effects of DESO were more pronounced than those of DMSO.

Significance and Impact of the Study: Diethylsulphoxide determines essential biological and therapeutic properties that make its application preferable.