EXPOSURE TO ETHANOL UP-REGULATES THE EXPRESSION OF MYCOBACTERIUM-AVIUM COMPLEX PROTEINS ASSOCIATED WITH BACTERIAL VIRULENCE

Mycobacterium avium complex (MAC) organisms are the most common bacter ial cause of disseminated infection in patients with AIDS. MAC, facult ative intracellular bacteria, invade and multiply within macrophages. Treatment of MAC-infected macrophages with ethanol (10-100 mug/dL) is associated with increased intracellular multiplication of MAC. To inve stigate whether this enhanced growth is due to a stress-related respon se induced by nonlethal concentrations of ethanol, strain 101 (serovar 1) was exposed to ethanol, and the regulation of the expression of pr oteins was examined. Exposure of MAC to ethanol (range, 10-100 mug/dL) was associated with up-regulation of the expression of a number of ba cterial proteins, some of which (65 and 33 kDa) interfered with macrop hage functions, such as production of superoxide anion and killing of Staphylococcus aureus. Thus, exposure of MAC to small concentrations o f ethanol may induce a stress-related response with consequent increas e in the synthesis of proteins possibly associated with its ability to survive within macrophages.