WHY DO SPUTUM CULTURES FAIL TO YIELD PATHOGENS?

The simple procedures of sputum homogenization and incubation in a carbon dioxide enriched atmosphere markedly increased the isolation rates of sputum pathogens from 53 purulent specimens. Without these procedures, Haemophilus influenzae was recognized in 25% and pneumococci in 34% of specimens, whereas the yield increased to 66% and 49% respectively when the specimens were processed in this manner.