Definition of Mycobacterium avium complex in US English:

Mycobacterium avium complex

noun

Medicine
  • (More fully "Mycobacterium avium-intracellulare complex") mycobacteria of the closely related species Mycobacterium avium and M. intracellulare; (also) opportunistic infection caused by bacteria of this group, seen especially in AIDS patients. Abbreviated MAC, MAI.

Origin

1970s.