A recent study published in PLOS One revealed that home washing machines may not effectively eliminate dangerous bacteria from healthcare workers' uniforms, potentially contributing to the spread of antibiotic-resistant pathogens. The study found that one-third of the washing machines tested did not pass the hygienic washing test in the standard cycle.
"Hospital-acquired infections are a major public health issue, partly because they often involve antibiotic-resistant bacteria, including Pseudomonas aeruginosa, Enterococcus faecium, and Staphylococcus aureus," the study reported. These bacteria are known to cause severe infections and are classified as critical by the World Health Organization.
The researchers tested the washing machines using both quick and normal cycles, with and without biological detergents, to assess their decontamination capacity. The study found that domestic washing machines are particularly ineffective at eliminating these bacteria during short and low-temperature cycles. During quick cycles, three of the six machines did not exceed 44 degrees Celsius, and 50 percent of the machines failed to decontaminate the laundry. Moreover, none of the washing machines reached the 60 degrees Celsius recommended by the British National Health Service for the effective hygienization of uniforms, even in normal cycles.
"Prolonged exposure to household detergents may even reinforce this resistance, making them more difficult to eliminate," the researchers warned, according to Spektrum der Wissenschaft. They also discovered bacterial biofilms inside many of the washing machines, identifying 94 different microorganisms in these biofilms, one-third of which are considered potentially pathogenic to humans. DNA sequencing identified potentially pathogenic genera, particularly Mycobacterium, Pseudomonas, and Acinetobacter, and revealed the presence of antibiotic resistance genes.
"Enterococcus faecium can survive at least 20 days on cotton," the study noted. Bacteria within biofilms can transfer resistance genes to each other, further promoting antibiotic resistance.
"Relying exclusively on domestic washing machines is insufficient for preventing the spread of dangerous microbes among healthcare workers," emphasized Professor Katie Laird, a microbiologist involved in the study. "If detergents are used at levels lower than necessary to kill the bacteria, these microorganisms are exposed to a level of detergent to which they can become resistant," she explained, according to Agencia SINC.
As a solution, the study suggests that healthcare facilities should have industrial washing machines on their premises to wash uniforms. Using industrial washing machines could improve patient safety and control the spread of antibiotic-resistant pathogens. Unlike domestic washing machines, industrial washing machines are monitored to ensure that disinfection levels are met.
"If effective measures are not adopted, these bacteria will continue to spread silently, putting patients, professionals, and the community at large at risk," the researchers cautioned, according to Postal do Algarve. They propose that the washing guidelines given to healthcare workers be reviewed to ensure that home washing machines clean effectively or, preferably, that uniforms be washed in industrial machines.
The article was written with the assistance of a news analysis system.