Chapter 67 : Risk of Exposure in Hospitals Colonized with Legionellae

Abstract:

The incidence of Legionnaires' disease in Slovakia is low (0.2/million people), though underestimated; only a few sporadic cases have been documented. This chapter presents a study focused on an investigation of a potable water system for Legionella contamination and an evaluation of the risk of possible exposure, reflecting seroreactivity or even infection of nosocomial origin in patients of the hospital, where laboratory diagnostic tests for Legionella infection are not performed. The quantitative contamination of the water distribution system was 104 to 107 CFU/liter and was supported by the presence of legionellae in water from central and P3 tanks. Contamination was supported by legionellae surviving in the central tank, promoted by the nonadequate maintenance of the tank, especially in a temperature regimen (50 to 52№C) and hypochlorination. To assess the risk of exposure to contaminated tap water for inpatients, the authors did a serosurvey for antibodies in patients submitted to a normal treatment regimen from block A, colonized with legionellae in 20 to 45% from 1995 to 1999. A small group of patients suffering from pneumonia (more than 100) in the same hospital in which Legionella laboratory tests are not in routine use, was investigated in order to find another explanation for the absence of nosocomial legionellosis. There was a lack of convalescent-phase sera and samples for cultivation due to insufficient cooperation with clinicians and notably missing detection by Legionella urinary test. This test is widely recommended for active surveillance of legionellosis in colonized hospitals.