Clean touch: germ-free plastics

Clean touch: germ-free plastics
Sports clubs, trams, public toilets: there is a risk of infection at any of the places that thousands of people frequent day in, day out.

A slimy coating (“biofilm”) containing what are sometimes pathogenic bacteria and fungi that reproduce readily develops on door and grab handles or sanitary fittings as a result of repeated skin contact.

A fleeting touch and the germs have already been passed on: unless hands are washed thoroughly, the germs get into the body and represent a particular danger to people with weakened immune systems – they face the threat of severe illnesses, from heavy diarrhoea to meningitis. So is it always necessary to reach for a disinfectant spray? A simpler solution is if the materials used have an integrated antiseptic, i.e. germicidal, function.

Hygiene is a serious problem, particularly in hospitals, where more and more extremely dangerous pathogens can be found, such as the multi-resistant bacterium Staphylococcus aureus (MRSA) that causes pneumonia and carditis and cannot be treated successfully with antibiotics any more. According to the European Centre for Disease Prevention and Control (ECDC), about 50,000 of the roughly three million infections that occur in European hospitals every year are fatal.

Clean touch: germ-free plastics

There are dangers everywhere. The U-shaped pipes (traps) located underneath the washbasins in patients’ rooms are an underestimated source of pathogens, for example.

The magazine “Management & Krankenhaus” warns that the liquid retained in the trap contains up to ten billion living germs per millilitre. It is reported that aerosol formation leads to the transfer of them to the hands of hospital staff, where Pseudomonas aeruginosa – which causes urinary tract infections, pneumonia and meningitis – survives for longer than an hour.

Enough time to be passed on to patients during care activities. Nosocomial infections (the term comes from the Greek words “nosos” = “illness” and “komein” = “care”) are also attributable to contaminated medical devices, drugs and food.

Killing germs and interrupting transmission channels is therefore the name of the game in hospital hygiene. All objects and surfaces on which biofilms can form – particularly when they are made of plastic, which has surfaces that are anything but smooth and which microorganisms find it easy to settle on – are candidates for physical and/or chemical disinfection measures, such as heating, irradiation, wet and dry sterilisation.

It proves to be a problem to fight contamination by conventional means, because disinfectants containing chlorine are very hard on polymer construction and other materials such as drinking water pipes: the surface of the material corrodes, roughens and repels dirt less effectively, creating an environment in which bacteria can thrive particularly well.

Since plastic is so versatile and economic that it can only be substituted by other materials to a very limited extent, it is not uncommon for different processes to be needed to guarantee freedom from germs.

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