Staphylococcus aureus pneumonia is rare, accounting for 1% of community-acquired cases and 10% of hospital-acquired cases. Among community-acquired cases, we report those associated with the isolation of S. aureus strains producing a toxin that is very rarely characterized: Panton-Valentine leukocidin. This clinical entity, known as necrotizing staphylococcal pneumonia, is associated with acute necrotizing and hemorrhagic pneumonia, leukopenia, and a high mortality rate of 75%. Between 1986 and 1998 at the National Reference Center for Staphylococcal Toxemia (CNR-TS), the gene encoding Panton-Valentine leukocidin was identified in 22 S. aureus strains isolated from cases of pneumonia. Retrospective analysis of clinical records was possible for 8 cases. During a prospective study conducted in 1999 on S. aureus pneumonia, 119 strains associated with pneumonia were submitted to the CNR-TS by the consulted microbiologists: the gene encoding Panton-Valentine leukocidin was found in 16 of these strains, but complete clinical information was obtained for only 8 cases. In total, we report 16 clinical observations collected between 1986 and 1999. (adapted from the text)