%0 English Abstract %T [Legionella spp. contamination in indoor air: preliminary results of an Italian multicenter study]. %A Montagna MT %A De Giglio O %A Napoli C %A Cannova L %A Cristina ML %A Deriu MG %A Delia SA %A Giuliano A %A Guida M %A Laganà P %A Liguori G %A Mura I %A Pennino F %A Rossini A %A Tardivo S %A Torre I %A Torregrossa MV %A Villafrate MR %A Albertini R %A Pasquarella C %J Epidemiol Prev %V 38 %N 6 %D Nov-Dec 2014 %M 25759346 %F 1.293 %R %X OBJECTIVE: To propose a standardized protocol for the evaluation of Legionella contamination in air.
METHODS: A bathroom having a Legionella contamination in water >1,000 cfu/l was selected in 10 different healthcare facilities. Air contamination was assessed by active (Surface Air System, SAS) and passive (Index of Microbial Air, IMA) sampling for 8 hours, about 1 m away from the floor and 50 cm from the tap water. Two hundred liters of air were sampled by SAS every 12 min, after flushing water for 2 min. The IMA value was calculated as the mean value of colony forming units/16 plates exposed during sampling (2 plates/hour). Water contamination was evaluated at T0, after 4 and 8 hours, according to the standard methods.
RESULTS: Air contamination by Legionella was found in three healthcare facilities (one with active and two with passive sampling), showing a concomitant tap water contamination (median=40,000; range 1,100-43,000 cfu/l). The remaining seven hospitals isolated Legionella spp. exclusively from water samples (median=8,000; range 1,200-70,000 cfu/l).
CONCLUSIONS: Our data suggest that environmental Legionella contamination cannot be assessed only through the air sampling, even in the presence of an important water contamination.