Atypical pneumonia.

PURPOSE OF REVIEW: We present the key advances in the infections that clinicians conventionally associate with atypical pneumonia: legionellosis, Mycoplasma pneumonia, Chlamydophila species pneumonia and Q fever.

RECENT FINDINGS: There have been significant developments in molecular diagnosis to include Mycoplasma pneumoniae and Chlamydophila pneumoniae in multiplex PCR of respiratory specimens. There are diagnostic challenges in distinguishing carriage from infection, which is recognized in C. pneumoniae and now also evident in M. pneumoniae. Macrolide-resistant M. pneumoniae has emerged in Asia. There are new antimicrobials on the horizon in the ketolide class with activity against typical and atypical pathogens and useful empirical agents.

SUMMARY: There are few advances in our knowledge of the epidemiology of atypical pathogens or the effectiveness of antimicrobial therapy--empirical or pathogen specific. However, if molecular testing becomes widely implemented, there will be an increased understanding of the epidemiology and presentation of atypical pneumonia and a shift to more targeted antimicrobial therapy.