This patient has a CURB-65 score of 4 (C), indicating a severe pneumonia and a mortality risk of 15-50 per cent.

Organisms in atypical pneumonia

3 D From the list of answers above, H. influenzae (E) and S. pneumoniae (C) are organisms which are usually responsible for community-acquired pneumonia. S. aureus (A) and Pseudomonas spp. (B) are usually found in patients with hospital-acquired pneumonia. L. pneumophilia (D), along with Chlamydia spp. and Mycoplasma pneumoniae, are the atypical pneumonia-causing organisms. A urinary antigen test is routinely used for the detection of Legionella spp. Serological tests can be used for the detection of Mycoplasma and Chlamydia spp. and also Legionella spp.