O066: Thermal disinfection of bedpans: European ISO 15883-3 guideline requirements are insufficient to ensure elimination of ARE and OXA-48 outbreak-strains
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KeywordsInfectious Disease Bacterial Suspension Enterococcus Faecium Viable Count European Guideline
During 2012, our hospital was faced with a vancomycin-resistant Enterococcus faecium (VRE) outbreak. Washer-disinfectors are used for the cleaning and thermal disinfection of bedpans. The European guideline NEN-ISO 15883-3 (ISO) states that washer- disinfectors have to achieve a minimum A0 value of 60 for appropriate disinfection of bedpans (≈ 80 °C for 60 seconds or 90 °C for 6 seconds). However, previous data have shown that some E. faecium strains survive 60 seconds at 80 °C. Following ISO, the A0 measurement should include a cold (a minimum interval of 60 minutes since the machine was last used) and hot start.
We determining the A0 value of the VRE outbreak-strain and the outbreak-strain of the OXA-48 K.pneumoniae outbreak in another Dutch hospital during 2011. Moreover the impact of a cold start measurement on the A0 value was evaluated.
The minimum A0 value that results in the killing of all isolates was determined for both strains. Bacterial suspensions were heated at 65, 75 and 80 °C and samples for viable counts were obtained after 1,2,3 and 10 minutes at each temperature. VRE PCR and cultures were performed on bedpan swabs after disinfection; hot and cold start measurements were compared.
Adequate killing required a minimum A0 value of 180 for the VRE outbreak strain and 120 for the OXA-48 K.pneumoniae. The cold start resulted in a 30% lower A0 value, than the hot start. All washer-disinfectors in our hospital functioned in agreement with the European guideline, although the lowest A0 value was 73, only just above 60. Swabs taken from bedpans processed in these washers with low A0 values , were VRE-positive by PCR and cultures.
Both outbreak strains survived the A0 value of 60 required in the ISO. VRE were identified by PCR as well as cultures of bedpans that had been disinfected by these washer-disinfector. We suggest to increase the minimal acceptable A0 value of washer-disinfectors to at least 180. Furthermore, the cold-start is needed for adequate A0-value measurement.
Disclosure of interest
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.