Research for infection protection

NEWS: German Disinfectants Commission recommends hygienic microbiological checks of wipes dispensers used for surface disinfection

In its recent recommendation (March 2013), the Disinfectants Commission of the Association for Applied Hygiene (Verbund für angewandte Hygiene e.V./VAH) urges hygienic microbiological controls when applying dispenser systems for pre-soaked surface disinfection wipes in the clinical setting [1].

Wipes dispensers filled with surface disinfectants based on surface-active substances may develop biofilms inside when not reprocessed properly before reuse. The disinfection solution may become contaminated microbially, particularly with Gram-negative pathogens. (Background information on the safe reprocessing of wipes dispensers)


Recommendations for clinical risk areas

Against this background, the Disinfectants Commission of the German Association for Applied Hygiene (VAH) strongly recommends conducting hygienic microbiological checks when applying dispenser systems for pre-soaked surface disinfection wipes in the clinical setting. Solutions used in risk-area wipes dispensers, for example in neonatology, intensive care or burn units, should be subjected to laboratory examination (standardised method) once per year. After the specified period of use or after the tissues are used up, proceed as follows:

  1. Carry out a membrane filtration of 10 ml of the disinfection solution in the wipes dispenser (0.45 µm pore size)
  2. Afterwards, rinse with 100 ml of 0.9 % NaCl solution
  3. Use sterile forceps to place the membrane filter (preferably free from air bubbles) on casein peptone-soymeal peptone agar with an inhibitor validated in the product expertise (e.g. 3 % Tween 80; 3 % saponin; 0.1 % histidine; 0.1 % cysteine)
  4. Incubate for 72 hours at 37 °C

A hospital hygienist assesses the results. The threshold value for Gram-negative microorganisms is 0 CFU/10 ml; for airborne spore formers and other non-pathogenic ambient flora the value is 3 CFU/10 ml.


Recommendations for lower-risk areas

In areas involving lower risk of infection, it is, for the time being, sufficient to carry out random annual checks with dip slides. If the results indicate a growth of microorganisms, it has to be assumed that actual contamination is considerably higher. In this case, the reprocessing procedure for wipes dispensers needs to be adjusted (if necessary, new wipes dispensers have to be used).

The search for possible contamination sources should consider, for instance, the quality of the water used for preparing the solution, the disinfectant dosing device, the environment where dispensers are filled, and the reprocessing of the wipes dispensers.


Literature:
1. Desinfektionsmittel-Kommission im Verbund für angewandte Hygiene e.V.: Kontrollmaßnahmen bei der Anwendung von Tuchspendersystemen für die Flächendesinfektion in Abhängigkeit vom Risikoprofil. In: Hygiene & Medizin 2013, 38 (3): 108–109.

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Microbiological checks of dispensers for pre-saturated surface disinfection wipes