Almost everyone likes the scent of fresh linen. But this scent can be deceiving.
Because researchers have now proven: Even fresh laundry can be contaminated with germs. And the bacteria can spread to humans – even those that can pose a health hazard.
"We have demonstrated for the first time that a washing machine can also be used to transfer antibiotic-resistant germs to humans," explains Martin Exner, Director of the Hygiene Institute IHPH at the University Hospital Bonn. The researchers report on their study in the journal "Applied and Environmental Microbiology".
Specifically, the researchers have demonstrated the transmission of Klebsiella oxytoca pathogens in a children's hospital in a commercial washing machine. In routine clinical trials, a bacterium has been detected in newborns several times, which can lead to gastrointestinal or respiratory tract infections, even fatal blood poisoning. An antibiotic would have limited or even no help against the identified pathogen. Fortunately, the babies did not have an infection. But the hospital staff was at first puzzled how the germs could spread despite intensive hygiene measures. So the experts were added.
Because the type of bacteria was quite rare, the researchers were able to understand its distribution path well. And exclude that the parents and the staff had introduced the germ.
They finally found what they were looking for in the washing machine's washing compartment and in the door rubber, says Schmithausen. The germs had come over the gently washed Strickmützchen and socks to the infants. How the germs could get into the machine is still unclear. It is conceivable that they were stuck in the filled laundry or got in over the operator, for example, when this was carried on the hands.
It is clear that the trend to wash for environmental protection and energy saving short and at low temperatures, could be counterproductive for people sensitive to health. Because to kill germs, it needs at least 60 degrees, says Schmithausen. The addition of chemical disinfectants could be useful. In this case, the protection of people who are immune-defended has priority over environmental aspects.
The findings of the researchers also apply to the home. For healthy people who use a normal washing machine, but the result has no consequences, says study director Ricarda Schmithausen. Because: "For a person with an intact immune system, there is no danger from resistant pathogens, even if he should carry such a germ in his mucous membranes."
On the other hand, physicians see a potential risk for vulnerable groups: immune-compromised people, those seriously ill who have chronic wounds or who live with indwelling catheters, people with festering injuries or infections, and newborn babies.
Hygienist Christian Brandt considers the Bonn investigation a "milestone". It has long been suspected that multi-resistant pathogens are transferred via clean laundry from the washing machine to humans – now it has actually been proven, says the director of the Institute of Hygiene Vivantes clinics in Berlin.
Bacteria quickly die in drought, they thrive in moisture. High wash temperatures, dryers and irons are considered bacteria killers. "Unfortunately, many garments today are no longer washable at 60 degrees, a possible uncertainty factor," said Brandt. Even if you wash at 60 degrees, this temperature is often not reached in conventional machines in places such as drawer, pump or door, pathogens could possibly survive there.
For decades, hospitals and nursing homes have set high standards for the quality of washing procedures for hospital textiles, says the hygiene expert. There are usually washed with disinfectant detergents and high temperatures.
According to estimates from a "Lancet" study, multidrug-resistant germs cause 33,000 deaths per year across Europe, so that about 2,300 people die in Germany. If antibiotics are no longer effective, even minor infections can be life-threatening. About three-quarters of such illnesses occur in hospitals and other health care facilities, researchers write. Therefore, experts demand that patients should use antibiotics responsibly, and that the drugs should only be taken or prescribed when they are really needed. In addition, it requires more research on new resources, but this is complicated and expensive.