Bus Water Storage Tank as a Reservoir of Legionella pneumophila

Anamarija Jurčev-Savičević, Nikola Bradarić, Vlado Ožić Paić, Rosanda Mulić, Dinko Puntarić, Kornelija Miše

Abstract


 

Health concerns associated with Legionnaires’ disease have been identified as an area of the increasing public and professional interest. Any natural water or man-made water systems worldwide might be reservoirs of Legionellae. We presented a sporadic, community-acquired case of Legionnaires’ disease caused by Legionella pneumophila serogroup 1 in a bus driver who used water for hand and face washing from a bus water storage tank. The history of any other usual place of exposure to Legionellae was negative. The water from the tank was dirty, filled with sediment and leaves, at the temperature of 22° C. The water was heavily contaminated with Legionella pneumophila serogroup 1 isolated from each sample with the concentration of 66,000, 16,000, 42,000, 56,000 and 34,000 CFU/L.

The disinfection of the bus water storage tank was made using hyperclorination with 50 mg/L of free residual chlorine. The control sampling one week after the disinfection yielded negative results.

So far, there are no recommendations on regular management or disinfection of water in bus storage tanks, but it seems to be reasonable to assume that passengers as well as bus drivers may be exposed to Legionella and therefore at risk of acquiring the infection. These recommendations should include regular empting, rinsing and filling the tank with fresh tap water, at least once a week.

Finally, we have to be aware that Legionella bacteria are ubiquitous and any potential mode of producing contaminated aerosol should not be overlooked during an epidemiological field investigation and proposed appropriate measures.

 


Keywords*


Legionellae, Legionella pneumophila, Legionnaires’ disease, bus, public transport, water storage tank, hyperclorination, prevention, Croatia

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