A narrative review with grounded theory to evaluate the evidence for cleaning the filter body of point-of-use tap water filters

Background

Point-of-use filters are installed at tap/shower outlets in hospitals in response to either water-related outbreaks/incidents where water-borne pathogens (e.g. Pseudomonas aeruginosa) have been isolated in a patient or in the water supply, or as a prophylactic measure in areas of high risk where immunocompromised patients are being treated (e.g. intensive care or neonatal units).

Methods

This narrative review considers the evidence base for external cleaning of the body of these filters, and utilizes a unique approach by combining grounded theory with standard narrative review techniques. This was felt necessary and appropriate in order to extract relevant data from a limited evidence base.

Results

No studies met the criteria for inclusion in the narrative review process; however, the inclusion of grounded theory provided evidence of five key themes in the literature: retrograde contamination; cleaning; maintenance/training; system contamination; and flushing/sampling.

Conclusion

These themes provide a narrative structure where the evidence for each theme is discussed. Axial coding explores the evidence for links between these themes. Behavioural implications are raised, as is evidence of flaws in current studies, such as the significant risk of confounding due to a complex range of variables in the clinical setting. This approach has collated and defined the risks and likely factors related to filter body contamination, and provided clear questions regarding cleaning which must be answered through further scientific study.