Legionella Pneumophila Contamination in Condensed and Cooling Water of CACS at Public Places in Southern Jiangsu in 2011-2014

Objectives  To understand the contamination of legionella pneumophila in cooling and condensed water from centralized air conditioning system in public places in southern Jiangsu.

Methods  Based on the methods in the Hygienic Specifications of Air Conditioning Ventilation Systems in Public Buildings (WS 394-2012), water samples were collected in 2011-2014 for the detection of legionella pneumophila.

Results  The situation of cleaning and disinfection for centralized air conditioning system in 98 public places surveyed in 2011-2014 were significantly different.The detection rate of legionella pneumophila in 179 cooling and condensed water samples was 22.9%; which was 30.4% in 2011, 36.4% in 2012, 8.7% in 2013 and 0% in 2014.The detection rates of 101 cooling and condensed water samples collected from hotels were 19.2% and 28.6%, respectively; and the detection rates of 78 cooling and condensed water samples collected from shopping malls or supermarkets were 21.9% and 35.7%, respectively.The detection rate of 137 cooling water samples and 42 condensed water samples were 20.4% and 31.0%, respectively.

Conclusions  Compared with those in 2011 and 2012, the detection rates of legionella pneumophila in 2013 and 2014 was reduced significantly.But there were still potential threats to the public health, the administration and management of centralized air conditioning system should continue to be strengthened.