Rate of Legionella pneumophila colonization in hospital hot water network after time flow taps installation

In hospital water systems legionellae may be resistant to disinfectants in pipework, which is a problem particularly in areas where there is low flow or stagnation of water. We evaluated legionella colonization of a water network of an Italian hospital after time flow taps (TFTs) installation in proximity to dead legs. The water volume flushed was 64 L/day from May 2016, and 192 L/day from December 2016. Before TFTs installation, Legionella pneumophila sg2-14 was detected in all points (4 x 10(4) +/- 3.1 x 10(4) cfu/L). All sites remained positive (2.9 x 10(4) +/- 1.9 x 10(4) cfu/L) through November 2016. From December 2016 legionella persisted in one point only (2 x 10(2) to 6.8 x 10(3) cfu/L). TFTs with chemical disinfection may reduce legionella colonization associated with dead legs. (C) 2017 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.