Introduction / objectives
Hospital water systems have regularly been shown to serve as a reservoir for waterborne pathogens such as Legionella spp, Mycobacteria spp and fungi, all able to cause life-threatening infections especially in immunocompromised patients. In this study, the suitability of new point-of-use water filters was evaluated in a clinical setting.
During a routine control of hospital water, contamination with Legionella spp. was detected. To protect the patients from exposure to Legionella, shower heads were replaced by point-of-use shower filters (H2OK medical filters, Norit Filtrix, The Netherlands). The efficacy of 4 shower filters was tested during 5 weeks. Water samples were taken with and without use of the shower filter and were analyzed for the presence of Legionella, heterotrophic plate count (HPC), and fungi. After 5 weeks of use, shower filters were examined using scanning electron microscopy (SEM).
96% of the samples taken without the filter were positive for Legionella whereas all filtered water samples were Legionella free. Although other bacteria were present in the filtered water, the HPC was significantly reduced compared to the unfiltered water. Fusarium oxysporum and Fusarium solani were regularly detected in samples taken without shower filter but were never observed in filtered samples. SEM analysis showed a variety of structures on the inner side of the filter membranes while the outside of the membrane did not show any changes compared to an unused control filter.
The point-of-use filters proved to be highly effective in eliminating potentially pathogenic Legionella and Fusarium species from the showering water. The effects were seen over the complete 5 week study period.
Disclosure of interest