Legionella infection risk from domestic hot water.
We investigated Legionella and Pseudomonas contamination of hot water in a cross-sectional multicentric survey in Italy. Chemical parameters (hardness, free chlorine, and trace elements) were determined. Legionella spp. were detected in 33 (22.6%) and Pseudomonas spp. in 56 (38.4%) of 146 samples. Some factors associated with Legionella contamination were heater type, tank distance and capacity, water plant age, and mineral content. Pseudomonas presence was influenced by water source, hardness, free chlorine, and temperature. Legionella contamination was associated with a centralized heater, distance from the heater point >10 m, and a water plant >10 years old. Furthermore, zinc levels of <100 microg/L and copper levels of >50 microg/L appeared to be protective against Legionella colonization [corrected]. Legionella species and serogroups were differently distributed according to heater type, water temperature, and free chlorine, suggesting that Legionella strains may have a different sensibility and resistance to environmental factors and different ecologic niches.
Borella
Paola
P
Dipartamento di Scienze Igienistiche, Microbiologiche e Biostatistiche, University of Modena and Reggio E., Via Campi 287, I-41100 Modena, Italy. borella.paola@unimore.it
Montagna
M Teresa
MT
Romano-Spica
Vincenzo
V
Stampi
Serena
S
Stancanelli
Giovanna
G
Triassi
Maria
M
Neglia
Rachele
R
Marchesi
Isabella
I
Fantuzzi
Guglielmina
G
Tatò
Daniela
D
Napoli
Christian
C
Quaranta
Gianluigi
G
Laurenti
Patrizia
P
Leoni
Erica
E
De Luca
Giovanna
G
Ossi
Cristina
C
Moro
Matteo
M
Ribera D'Alcalà
Gabriella
G
D006801:Humans; D007558:Italy; D007875:Legionella / Q000302:isolation & purification*; D016952:Legionella pneumophila / Q000302:isolation & purification*; D007876:Legionellosis / Q000209:etiology*; D007877:Legionnaires' Disease / Q000209:etiology*; D008670:Metals / Q000032:analysis*; D011549:Pseudomonas / Q000302:isolation & purification*; D012307:Risk Factors; D014871:Water Microbiology; D014881:Water Supply / Q000032:analysis*
D008670:Metals