Occurrence of Legionella spp. in social welfare homes in Poland

Introduction and objective Legionellosis is a disease caused by water contaminated with Legionella bacteria. The quality of water is particularly important in in-patient health care facilities, as well as in facilities providing care for immunosuppressed patients, such as social welfare homes. The aim of the study was assessment of the occurrence of Legionella spp. in water systems of social welfare homes during 2014–2016. Material and methods The material for the study were water samples collected in the years 2014–2016 from 56 social welfare homes in Poland by employees of Sanitary-Epidemiological Stations. Samples were collected in accordance with the standard PN-EN ISO 19458: 2007, and tested in accordance with the standards in effect in Poland: PN-EN ISO 11731–2:2008 and PN-ISO 11731: 2002 [PN-EN ISO 11731–2: 2008]. Results The results of the study were divided into three groups, according to the number of bacterial colonies detected in water. During the analyzed period the highest percentage of social welfare homes from Group 3 (exceeding the standard) was found in 2014 and 2015 (3.5%), while in 2016 it was 1.7%. No statistically significant differences in the number of bacterial colonies in water were observed in the analyzed years. Conclusions High colonization of water with Legionella spp bacteria was found in the analyzed social welfare homes. The state of health of social welfare homes residents requires constant and frequent epidemiological supervision of the water systems.