Preventing nosocomial water- borne infections by controlling water and water systems. Leif Percival Andersen Head of Infection Control Copenhagen University Hospital, Rigshospitalet Denmark

 External water supply:  surface water  ground water  Internal water supply:  taps,  showers  supply to equipment. Water supply

 External water supply  Public,  Private  Surface water, lakes, rivers etc.  Ground water, wells etc. External water supply

 External water supply  Intent to have a low microbial content.  Differs considerable around the world.  The quality of the internal water supply is not better than the quality of the external water supply. External water supply

External water supply. Surface water

External water supply. Ground water.

External water supply. Bottle water.

 Internal water supply  Tap water,  Showers,  Water for equipment  dental units,  dialyze units  ice cube machines  Water coolers  etc. Internal water supply

Complexity of water supply.

 Internal water supply have two phases:  1) Liquid phase with planktonic bacteria.  2) Semisolid phase with microbial biofilm. Internal water supply

 Planktonic phase is free-living bacteria that does not adhere to surfaces.  This is the total germ count and Legionella germ count is measured routinely. Planktonic phase

 Biofilm consist of planktonic microorganisms that have adhered to surfaces (pipes, taps, aerators etc.) and produce a matrix of glycoproteins, that protect the dormant forms of microorganisms. Semisolid phase: biofilm.

Biofilm formation.

 Microorganisms in external water supply.  Water flow.  Construction of pipe system.  Material of pipes.  “Dead ends” What increases biofilm formation.

 Low water flow increases biofilm formation.  Taps acts as ”dead ends” when they are closed.  In ”dead ends” both planktonic and biofilm microorganisms are increased considerable. Water flow

 Valves, bows etc. increases the turbulence in the water system.  Turbulence increases the formation of biofilm. Construction of pipes.

 Stainless steel and PVC causes the lowest biofilm formation.  Results with copper are variable.  All other materials seem to increase the biofilm formation. Material of pipes.

Water systems.

Constructions and dead ends.

 Construction of taps.  Aerators on taps.  Shower tubes.  Shower heads.  Attachment of machines and equipment. End-point for water.

Taps, aerators and showers.

 Drains have a high content of biofilm and different bacteria both from water, patients and staff including pathogenic bacteria.  These bacteria can be released when the drain is washed down or used. Drains

 Aerators on taps  Even though P. aeruginosa is absent in water samples, it can often be found in imprints of aerators because of biofilm formation.  Shower tubes  Germ count in showers increases 1-4 log 10 within two days because of biofilm formation in shower tubes. Examples of increased germ count.

 Most commonly it is bacteria that form biofilm in water systems, but parasites may be in- cooperated in the biofilm.  Sequencing of biofilms has revealed more than 100 different bacteria in the same biofilm. Which microorganisms form biofilm?

 Most bacteria spp. are able to produce biofilm.  Not all bacteria are equally good in formation of biofilm.  Not all strains of the same bacteria species are equal good in biofilm formation. Which microorganisms form biofilm?

 Water-borne bacteria that most often causes human infection:  Legionella spp. primary L. pneumophilae  Pseudomonas aeruginosa  Acinetobacter spp.  Stenotrophomonas maltophilia Which water-borne micro- organisms cause human infection?

 Other species may occasionally cause infection in immune compromised patients:  Sphingomonas spp.  Brevibacterium spp.  Methylobacterium spp.  Xanthamonas spp. Other water-borne microorganisms that may cause human infection.

 Is traditional water sampling reliable or should germs in biofilm also be measured?  More than 90% of bacteria in water are viable, but non-culturable.  Germ count in biofilm need molecular techniques such as sequencing. Water sampling

 Most human-pathogenic bacteria are culturable, but does the number corresponds with the amount that may be released from biofilm?  In our experience we do not see infections in patients when total germ count is less than 5,000 germ/L and Legionella germ count is less than 1,000 germ/L. Water sampling

 Never use water supply from old buildings.  There are several descriptions of water supply to new hospital buildings that are connected to water systems in old buildings with high germ count.  Both cold and hot water supply should be taken from its own well or main water supply. How to prevent water-borne infections (systems).

 Keep a high water flow.  Both construction and frequent use of water systems are important.  A high water flow will reduce the thickness of the biofilm and thereby reduce liberation of planktonic bacteria. How to prevent water-borne infections (systems).

 Avoid ”dead” ends including showers and sinks that are not or rarely used.  Pipes without water flow, sinks/taps and showers that are never used will contain still water where bacteria will propagate and cause retrograde contamination of the water system. How to prevent water-borne infections (systems).

 Minimize side lines, connections and valves in the pipe line system.  Side lines, connection valves etc. will cause turbulence in the water system which increases the formation of biofilm.  Strait pipes will have a linear water flow and little biofilm formation. How to prevent water-borne infections (systems).

 Construction of taps should be simple.  Recently nosocomial infections with Pseudomonas aeruginosa have been described in relation to electronic forceps.  Complex constructed taps may increase biofilm formation. Mixed hot and cold water is in the taps. How to prevent water-borne infections (end point).

 Aerators should have a program where they are cleaned regularly.  Aerators have large surfaces and where there are still water all time when taps not are in use and large biofilm formation occur especially with P. aeruginosa.  Regular cleaning of aerators are very important. How to prevent water-borne infections (end point).

 Dialyse machines  Osmotic water supply with low germ count and low endotoxins.  Heat disinfection daily  Dental units  Several long thin tubes to the instruments  Regularly heat or chemical disinfection can be adapted Water for equipment and apparatuses.

 Water coolers  Several different models – some with built-in disinfection (filter, UV-light).  Regular cleaning outside and inside  Ice cube machines  Several different models  Regular cleaning outside and inside Water for equipment and apparatuses.

 Sterile filter on taps and in showers.  Sterile filter on the tap or showerheads with sterile filter prevent infections with water-borne bacteria.  At Rigshospitalet it is used when nosocomial infections with water-borne bacteria are seen in a ward or if the germ count is repeatedly high. How to prevent water-borne infections (end point).

Nosocomial Legionella infections at Rigshospitalet.

Nosocomial P. aeruginosa septicemia at Rigshospitalet.

Nosocomial P. aeruginosa, Acinetobacter spp and S. maltophilia septicemia.

 It is possible to reduce nosocomial infections caused by water-borne bacteria, but it needs a great complex of interventions. Conclusion

A wet thank you. Questions?