Bacterial Infections and Aspiration

Patterns of lung involvement can vary, depending on the virulence of the organism and immune status of the host. The same organism can have different presentations in different hosts (for instance, MTB in immunocompetent patients and AIDS can have dissimilar imaging signs), whereas multiple different organisms may have similar imaging appearances depending on mechanism of injury and host response (for example, lobar consolidations commonly due to community-acquired Streptococcus pneumoniae, as well as from organisms such as Legionella and gram-negative bacteria such as Klebsiella).