SANITARY WATER

Monitoring of sanitary water quality in healthcare establishments and public buildings

Legionella and Pseudomonas aeruginosa – the principle waterborne sanitary risks

Presence of vulnerable population in healthcare establishments makes water quality extremely important, particularly concerning contamination by pathogenic microorganisms, such as Legionella and Pseudomonas aeruginosa. 
Legionella, an aquatic bacteria present in all water installations, is the responsible agent of Legionella disease, a severe pneumonia with 10% mortality rate. The disease is contracted through the inhalation of aerosols containing Legionella bacteria. The people at risk are immune-compromised patients. The contamination in health-care establishments is often due to the use of contaminated showers and taps.  
Pseudomonas aeruginosa is a bacteria present in all environments: soil, wet matrices and all types of water. This bacterium is resistant to disinfections and is found frequently in hospitals. Pseudomonas aeruginosa is the causative agent of diverse more or less severe pathologies (infections of wounds, lungs, eyes) and complications are encountered in immune-compromised patients. The bacteria can be present in water networks, but patients or water users can contaminate the water installation by touching taps and showers (this event is called retro-contamination).
Different sanitary risks linked to water lead to the implementation of control measurements and survey plans of microbial proliferation on the different parts of sanitary water networks in hospitals or public buildings.

Surveillance of water quality using QGA™ kits

Mastering microbial risks (Legionella, Pseudomonas aeruginosa) in sanitary water networks requires the implementation of surveillance schemas based on fast and reliable technologies. 2^nd generation ATP-metry kits allow measurement of total viable flora in water samples in only 3 minutes. Quench-Gone Aqueous (QGA) kits quantify living microorganisms by the measurement of only Intracellular ATP. All living cells contain ATP- aerobic or anaerobic bacteria, protozoa, amoeba, and algae.  
Surveillance plans based on ATP-metry include microbial mapping of the water installation and the selection of critical points (critical zones include presence of biofilm, stagnant water, corrosion) to be controlled on regular basis as preventive actions.
The principal interest of this technology for health-care establishments is the reactivity for anticipating microbiological drifts even before Legionella isolation from  water samples  by classical culture –based techniques. Efficiency of disinfection actions can be immediately verified on all microorganisms, viable and cultivable but also on viable non cultivable microorganisms.  Corrective actions can be validated several days before reference methods deliver a result. Fragile patients in hospitals are thus better protected from waterborne pathogens.

Methodology for biological mapping of a water installation using QGA kit:

1. Establishment of the simplified architecture of the sanitary water network
2. Microbial mapping for localization of the critical zones for proliferation of microorganisms
3. Samples are collected on the totality of the water network – starting from the city network point of delivery up to the end users points – showers and taps. Only an exhaustive plan of the installation leads to an efficient methodical analysis of risks.  

This biological mapping will answer a very important question when a microbial disorder is detected: should the disinfection required be on the totality of the installation, one part of the installation or only on a specific terminal part?

1. Implementation and optimization of corrective disinfection actions
2. Evaluation of the efficiency of corrective actions

Results are immediately available (3 min per sample) and new decisions for treatment- disinfection can be undertaken during the same day for securing the installation.
After the validation of all the corrective actions, critical points are controlled on regular basis using QGA kit for early detection of new degradation or drift in microbial quality of water and securing water network.