Retrospective study of 30 cases of Legionellapneumonia in the Kansai region

Thirty Legionellapneumonia cases were clinically investigated retrospectively from 1999 to 2005 at the Respiratory Medicine Department of Kyoto University and affiliated hospitals. Twenty-eight cases were sporadic and two cases were part of an outbreak. The patients consisted of 28 men and 2 women, with a mean age of 58.8 years (range 25–87). Nineteen cases were smokers and 19 had some underlying disease. The mean period from the disease occurrence to presenting at a hospital was 4.8 days (range 1–15). The mean period from presenting at hospital to Legionellapneumonia diagnosis was 4.6 days (range 0–22). Urinary antigen detection tests for Legionella pneumophillawere performed for 25 cases, and resulted in the diagnosis of 22 cases. Other diagnostic tests with positive findings were culture (buffered charcoal–yeast extract agar, BCYE), the polymerase chain reaction (PCR) test, and serological diagnosis (enzyme immunoassay and microagglutination test). Legionellaspecies diagnosis was obtained by culture and serology for 13 cases: 10 cases had Legionella pneumophilaserogroup 1, 2 cases had Legionella pneumophilaserogroup 6, and 1 case had Legionella longbeachea. Fluoloquinolones (Fq) are most often used for therapy, especially in recent cases, and were predominantly the chosen treatment (70%). Death due to Legionellapneumonia occurred in 4 cases: 3 cases had severe underlying diseases, and 1 case took 18 days to diagnose (doctors' delay). To detect the majority of Legionellapneumonia cases, a combination of diagnostic examinations is still needed. Regarding the management of community-acquired pneumonia, both the cost and the indication of diagnostic examinations for Legionellainfection should be considered simultaneously.