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Water with high mineral content is unsuitable for reprocessing flexible endoscopes and accessory items. It may reduce the efficacy of biocides and leave mineral deposits on equipment.
Water hardness is determined by the amount of calcium and magnesium ions present in the water. Water quality can be easily tested with test kits available from commercial manufacturers. Many health care facilities undertake a facility wide water treatment process.
For more information about your water quality contact the local water authority and also refer to the discussion of water quality in section two of AS/NZS 4187.
It is increasingly recognised that hospital tap water may be contaminated with a variety of microorganisms. Pseudomonas and related species, atypical mycobacteria and Legionella are the most important frequently detected contaminants.
Whether or not the hospital water is contaminated will depend on a wide variety of factors which include:
The principal risks of such contaminated water in endoscopy units are that:
This risk of clinical infection is likely to be extremely small and probably only significant where an invasive procedure, e.g. injection sclerotherapy or ERCP is undertaken or if the patient has a severely compromised immune system, (e.g. leukaemia,HIV infection).
Contamination of biopsy or culture specimens may also cause confusion by falsely suggesting that infection is present, (e.g. pseudo infection). This risk has prompted a call for filtration of all water used to wash and rinse endoscopes. Such a general usage is both difficult, expensive and may carry its own significant problems. Filters which are not changed and/or regenerated (for example by steam under pressure sterilisation) may in fact become a source of contamination themselves, increasing rather than reducing the problem. In general, however, persisting vegetative pathogens are unlikely to survive in a completely dry environment.
Bacteriological examination of tap water is not simple. The tap mouth should be flamed to eliminate surface gram negatives and at least a litre (preferably more) of tap water needs to be collected. Therefore, a practical alternative to monitoring water quality or filtering water is meticulous air drying of all channels following an alcohol flush after each case.
