Home washing machines fail to remove dangerous germs from textiles

Health care workers who wash their work clothes at home may inadvertently contribute to the spread of antibiotic-resistant infections in hospitals, according to a new study led by Katie Laird of De Montfort University published in the journal PLOS One.

Hospital infections are a major public health problem, in part because most cases involve antibiotic-resistant bacteria. Many nurses and health care workers wash their uniforms at home in regular washing machines, but some studies have shown that bacteria can be transmitted through clothing, raising the question of whether these machines can sufficiently prevent the spread of dangerous germs.

In the new study, researchers tested whether six models of household washing machines were successful in decontaminating health care workers’ uniforms by washing samples of contaminated fabric in hot water using a fast or regular cycle. Half of the machines failed to sanitize the clothing during the fast cycle, and one-third failed to clean the clothing sufficiently during the standard cycle.

The team also took biofilm samples from the inside of 12 washing machines. DNA sequencing revealed the presence of potentially pathogenic bacteria and antibiotic resistance genes. The research also showed that bacteria can develop resistance to household detergents, which also increases their resistance to some antibiotics.

The findings suggest that many home washing machines may not be effective enough to sanitize medical specialty clothing, which could contribute to the spread of hospital-acquired infections and antibiotic resistance. Researchers suggest revising the laundry guidelines given to healthcare workers to ensure that home washing machines are effective. Alternatively, healthcare facilities can use industrial machines to wash uniforms to improve patient safety and control the spread of antibiotic-resistant pathogens.

The authors add: “Our study shows that household washing machines often fail to disinfect textiles, allowing antibiotic-resistant bacteria to survive. If we are serious about transmitting infectious diseases through textiles and combating antimicrobial resistance, we must rethink how we wash our healthcare workers’ clothes.”