Legionella spp. and legionellosis in southeastern Italy: disease epidemiology and environmental surveillance in community and health care facilities

Abstract

BackgroundFollowing the publication of the Italian Guidelines for the control and prevention of legionellosis an environmental and clinical surveillance has been carried out in Southeastern Italy. The aim of the study is to identify the risk factors for the disease, so allowing better programming of the necessary prevention measures.MethodsDuring the period January 2000 - December 2009 the environmental surveillance was carried out by water sampling of 129 health care facilities (73 public and 56 private hospitals) and 533 buildings within the community (63 private apartments, 305 hotels, 19 offices, 4 churches, 116 gyms, 3 swimming pools and 23 schools). Water sampling and microbiological analysis were carried out following the Italian Guidelines. From January 2005, all facilities were subject to risk analysis through the use of a standardized report; the results were classified as good (G), medium (M) and bad (B). As well, all the clinical surveillance forms for legionellosis, which must be compiled by physicians and sent to the Regional Centre for Epidemiology (OER), were analyzed.ResultsLegionella spp. was found in 102 (79.1%) health care facilities and in 238 (44.7%) community buildings. The percentages for the contamination levels < 1,000, 1,000-10,000, > 10,000 cfu/L were respectively 33.1%, 53.4% and 13.5% for samples from health care facilities and 33.5%, 43.3% and 23.2% for samples from the community. Both in hospital and community environments, Legionella pneumophila serogroup (L. pn sg) 2-14 was the most frequently isolate (respectively 54.8% and 40.8% of positive samples), followed by L. pn sg 1 (respectively 31.3% and 33%). The study showed a significant association between M or B score at the risk analysis and Legionella spp. positive microbiological test results (p < 0.001). From clinical surveillance, during the period January 2001 - August 2009, 97 cases of legionellosis were reported to the OER: 88 of community origin and 9 nosocomial. The most frequent symptoms were: fever (93.8%), cough (70.1%), dyspnea (58.8%), shivering (56.7%). Radiological evidence of pneumonia was reported in 68%. The laboratory diagnostic methods used were: urinary antigen (54.3%), single antibody titer (19.8%), only seroconversion (11.1%), other diagnostic methods (14.8%).ConclusionsOur experience suggests that risk analysis and environmental microbiological surveillance should be carried out more frequently to control the environmental spread of Legionella spp. Furthermore, the laboratory diagnosis of legionellosis cannot be excluded only on the basis of a single negative test: some patients were positive to only one of the diagnostic tests.

Legionnaires’ disease in Italy: results of the epidemiological surveillance from 2000 to 2011

“…is a ubiquitous intracellular microorganism colonising natural and artificial aquatic environments, which grows at temperatures of 25 to 42°C [1][2]. Presently, a total of 55 species and more than 70 serogroups has been classified [3]; Legionella pneumophila serogroup 1 (Lp1) is the most frequently reported aetiological agent in community-acquired legionellosis, although also other serogroups, especially Lp4 and Lp6, are frequently involved in hospitalacquired cases and outbreaks, as well as other species commonly indicated as Legionella species (L. anisa, L. bozemanii, L. dumoffii, L. longbeachae, L. micdadei) [4][5][6][7][8][9].…”

“…Individual risk factors such as long-term medical conditions, heavy smoking or alcohol abuse, and environmental risk factors may influence the likelihood to develop the infection. The problem is particularly relevant in contaminated healthcare facilities because the onset of the disease and its outcome are influenced by the patient's pre-existing pathologies and level of immunocompetence [9,10]. In addition, medical equipment, if not adequately treated, can also be a potential source of infection in hospitals (endoscopes, food or nasogastric tubes, devices for artificial respiration and oxygen therapy, dental tools, etc.)…”

“…the search for sources of infection, periodical controls of drinking water supply systems, and installation of effective disinfection systems, have become a priority [9][10][11][12][13][14][15].…”

“…Since then, the number of sporadic and epidemic cases has been growing constantly, but the increase seems due to better reporting and/or improved diagnosis rather than to an increased incidence of the disease [9,17,18].…”

Beyond Traditional Biosafety

“…Surveys of U.S. hospitals have detected Legionella in 60% to 100% of water distribution systems (Kool et al, 1999;Vickers et al, 1987). Internationally, surveys have shown high rates of contamination in hospitals, hotels, offices, schools, and apartments (Goutziana et al, 2008;Mouchtouri et al, 2007;Napoli et al, 2010).…”