The value of the sputum gram's stain in community-acquired pneumonia.

Expectorated sputum Gram's stain was correlated with clinical presenting data, cultures, serological data, and response to antibiotic therapy in 89 patients admitted with community-acquired pneumonia. The finding of Gram-positive diplococci on Gram's stain correlated with brief antecedent illness, Streptococcus pneumoniae growing from cultures, and a rapid response to single-agent antibiotic therapy. Patients with no predominant pathogen on Gram's stain were clinically indistinguishable from those with Gram-positive diplococci except for a longer antecedent illness, lack of growth of pathogens from cultures, and more prolonged response to antibiotic therapy. Sputum cytological findings and transtracheal cultures were useful in patients with no Gram-positive diplococci on Gram's stain. The sputum Gram's stain is proposed as a sensitive and reliable indicator to guide therapy and predict outcome in adults with community-acquired pneumonia.