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Healthcare workers who wash their uniforms at home may unwittingly contribute to hospital-acquired infections (HAIs) and antimicrobial resistance, UK researchers warned.

An observational study by the Infectious Disease Research Group at De Montfort University, Leicester, found that domestic laundering may not sufficiently remove harmful microbes from healthcare clothing. 

Infection prevention measures often focus on hand hygiene and surface disinfection. However, the researchers explained that textiles can also serve as reservoirs for pathogens.

Pathogens Found on Curtains, Beds, and Scrubs

HAIs affect 10%-15% of hospitalised patients. Outbreaks have been linked to contaminated privacy curtains, surgical scrubs, medical equipment, mop heads, beds, and hospital linens. 

Studies have demonstrated that Pseudomonas aeruginosa, Escherichia coli, Enterococcus faecium, and Staphylococcus aureus can survive over 20 days on cotton. E faecium and S aureus remained viable for 7 days on polyester.

In the UK, hospital uniforms and linens are typically processed through in-house or industrial laundering systems designed to minimise microbial contamination. 

However, a recent study found that 86% of nurses in the UK washed their uniforms at home, where these infection control standards do not apply.

NHS Guidance for Home Laundering

NHS recommendations for domestic laundering include:

• Wash uniforms separately from other garments.
• Do not overload the washing machine.
• Wash at the highest possible temperature — 60°C for 10 minutes will kill almost all bacteria, and 30°C with detergent will kill methicillin-resistant S aureus (MRSA) and most other bacteria.
• Clean the washing machine regularly.

Limited Decontamination in Domestic Machines

Senior study author Professor Katie Laird noted that the United Kingdom is the only country in Europe where nurses routinely launder uniforms at home.

Her previous research showed that microorganisms can survive 40 °C washes and transfer between textiles during laundering.

“When healthcare workers launder their uniforms at home, they risk bringing microorganisms into their household environment,” she said. “[This]could be particularly serious if they live with vulnerable individuals,” Laird added.

To assess decontamination, researchers tested six domestic washing machines using E faecium bioindicators on contaminated fabric swatches under various wash cycles and detergent conditions. They used shotgun metagenomics to analyse bacterial communities and resistance genes. Detergent tolerance and antibiotic cross-resistance were tested in S aureus, Klebsiella pneumoniae, and P aeruginosa.

The study, published in PLoS ONE, found that only three of the six machines achieved sufficient decontamination (≥ 5 log₁₀ colony-forming unit reduction) at 60 °C during full-length wash cycles. Rapid cycles showed inconsistent results. 

Microbiome analysis revealed the presence of potentially pathogenic bacteria, including Mycobacterium, Pseudomonas, and Acinetobacter species. 

Resistance genes linked to efflux pumps and target modification were also detected.

Cross-Resistance Raises Further Concerns

The researchers found increased bacterial tolerance to detergents. Cross-resistance to antibiotics observed in S aureus and K pneumoniae, including to carbapenem and beta-lactam groups. 

Whole genome sequencing identified mutations in genes encoding efflux pump function following detergent exposure.

Call for Updated Laundering Standards

“Domestic laundering of healthcare uniforms may be insufficient for decontamination, posing risks for HAI transmission and antimicrobial resistance,” the researchers concluded. 

They said that owing to concerns about inadequate disinfection standards and the risks posed by biofilms in domestic washing machines, there was an “urgent need for stricter guidelines” and improved validation of washing parameters.

Alternatives such as on-site or industrial laundering should be considered to protect patient safety and reduce HAIs, they said.

The research was funded by De Montfort University and the Textile Services Association. 

Dr Sheena Meredith is an established medical writer, editor, and consultant in healthcare communications, with extensive experience writing for medical professionals and the general public. She is qualified in medicine and in law and medical ethics.