M. tuberculosis in a sputum smear is stained using fluorescent auramine with acridine orange counterstain

M. tuberculosis in a sputum smear is stained using fluorescent auramine with acridine orange counterstain; Mag.-950x.The auramine stain is absorbed by the Mycobacterium tuberculosis bacilli, which allows them to glow when view under the microscope using fluorescent lighting, and the acridine orange counterstain will promote visibility by reducing contrast.