| water-related nosocomial pneumonia caused by legionella pneumophila serogroups 1 and 10. | between august 1978 and november 1983, 21 cases of pneumonia caused by legionella pneumophila occurred in the leiden university hospital, mainly among immunocompromised patients. a new serogroup of l. pneumophila, designated serogroup 10 (prototype strain leiden 1), was isolated from bronchial secretions of four patients, and five patients had serological evidence of infection with this organism. nine patients had a culture-confirmed infection with l. pneumophila serogroup 1. l. pneumophila sero ... | 1985 | 4031547 |