Gamma-aminobutyric acid (GABA) production by eight common bacterial pathogens

Gamma-aminobutyric acid (GABA) is a potent amino acid neurotransmitter that suppresses normal neuronal activity in the central nervous system. Recently it has been suggested that GABA may play an important role in the pathogenesis of hepatic encephalopathy. In the present study GABA production by 8 common bacterial pathogens was measured during mid-log, stationary and mid-death phases of growth. All bacteria produced some GABA (range: 160-50 250 pmole/ml) with the majority of GABA production occurring during the mid-death phase of growth. These results suggest that the depressed levels of consciousness seen in patients with overwhelming sepsis or advanced liver disease and extraintestinal infection may in part be secondary to increased bacterial GABA production.