POTABLE WATER AND NOSOCOMIAL LEGIONNAIRES-DISEASE - CHECK WATER FROM ALL ROOMS IN WHICH PATIENT HAS STAYED

We studied 7 patients with nosocomial Legionnaires' disease to determi ne the relationship between isolates of Legionella pneumophila recover ed from potable water and those recovered from patients. Potable water was cultured from all rooms in which patients had stayed prior to the diagnosis of Legionnaires' disease. The 38 isolates of L. pneumophila (31 environmental, 7 patient) were resolved into 9 distinct patterns by pulse-field gel electrophoresis (PPGE), 3 by plasmid content and 2 each with monoclonal antibodies and conventional agarose gel electroph oresis of small fragments of DNA. Using PFGE it was determined that 4 of the 7 patients were infected with L. pneumophila identical to an is olate recovered from the potable water supply in one of the rooms each had occupied prior to the diagnosis of Legionnaires' disease. Patient s had resided in a mean of 3.57 rooms before a diagnosis of nosocomial Legionnaires' disease. We conclude that in the setting of contaminate d potable water and nosocomial Legionnaires' disease water from all th e rooms which the patient has occupied prior to this diagnosis should be cultured. PBGE of large DNA fragments discriminated best among the isolates of L. pneumophila.