Microbiological aspects of bacterial lower respiratory tract illness in children: atypical pathogens.

'Atypical' lower respiratory tract pathogens often cause a distinct identifiable syndrome in adults, but in children the clinical presentation of atypical, typical and viral pneumonia is less well differentiated. Specific microbiological investigations are usually required, but an understanding of their strengths and weaknesses is necessary to make interpretation possible. This review examines clinical presentation, microbiology and current evidence surrounding diagnostic techniques for Mycoplasma pneumoniae, Chlamydophila pneumoniae, Chlamydophila psittaci, Bordetella pertussis and Legionella species. Applying an understanding of the investigations to the diagnosis of pneumonia in children may lead to more appropriate patient management by ensuring that they clarify rather than further obscure the diagnosis.