Bacterial Structure, Classification, And Virulence Practice Test

A 62-year-old patient with AIDS (CD4 count of 40 cells/μL) develops a disseminated infection with Mycobacterium avium complex (MAC). He presents with fevers, night sweats, weight loss, and diarrhea. The organism is found in high numbers within macrophages throughout his reticuloendothelial system.

A 35-year-old immigrant from Southeast Asia presents with a chronic cough, night sweats, weight loss, and hemoptysis. A sputum sample is collected and subjected to a special staining procedure, which reveals red-staining rod-shaped organisms against a blue background. The bacterium's ability to resist decolorization by acid-alcohol is a key diagnostic feature.