Application study on aerosolreducing hygienic siphons


We experienced an outbreak of 4MRGN Pseudomonas aeruginosa (P. aeruginosa) on a phase B neurological rehabilitation ward. This multiphase outbreak had lasted several years and was sustained because of bacterial contamination from the waste water system. This is a concise report, highlighting the clinical findings from our comprehensive microbiological investigations conducted following the installation of the HygieneSiphon drain trap made by Aqua free GmbH.

Methods and Results:

All the patient basins on the ward had been barred from use. In November 2015 the action taken was to replace the horizontal corner waste pipes with conventional washbasins S-bend pipes and short variants of the HygieneSiphon trap were installed. To assess the new installation performance a clinical study was conducted in collaboration with the public health authority. It involved microbiological smears and direct contact tests of the traps, washbasins and aerators for 4 weeks following the installation of the HygieneSiphon traps. After 3 months the HygieneSiphon inserts were exchanged as specified by the manufacturer and these were also microbiologically tested. The microbiological investigation of the original installation (without the HygieneSiphon) showed that contamination of the washbasin occured from the original waste system after filling of the basin. Subsequent testing, once the HygieneSiphon had been installed and the pipework modifications made, showed no recurring contamination. However, after the service life of 3 months the HygieneSiphon inserts themselves became contaminated with pathogens brought in from the outside environment.


This study concludes that contamination of the washbasin and surrounding area with pathogens from the waste system can be prevented by the installation of the HygieneSiphon system. Therefore, in the event of an existing colonisation of the waste system with 4MRGN P. aeruginosa or other hygienically significant pathogens, we see the fitting of the HygieneSiphon as a cost effective, non-invasive method of preventing pathogenic contamination of the washbasin and surrounding area. Based on the results of this study, we believe that the HygieneSiphon can make an important contribution to reducing nosocomial colonisations/infections from sanitary installations.

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