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Background Disease outbreaks in healthcare facilities (e.g., Bacillus cereus) have been linked to contaminated linen, highlighting the importance of decontamination of healthcare textiles and infection control measures to prevent recontamination. The COVID-19 pandemic has raised further concerns around textile hygiene. Methods for monitoring microbial kill during healthcare laundering and post-laundering contamination are not standardised across Europe, leading to potential variation in validation outputs. For example, EN14065 accreditation requires microbiological monitoring, however no standard method is prescribed. Microbial kill is commonly validated by laundering inoculated textiles. Post-laundering hygiene monitoring tests can be destructive (elution) or non-destructive (e.g., swabbing). This study aims to evaluate common methods for detection of microbial contamination on textiles and measuring kill during industrial laundering processes. Methods Recovery of Escherichia coli, Staphylococcus aureus, Enterococcus faecium or Bacillus cereus spores (108, 102 and 101 CFU/ml) from 100% cotton was evaluated using different elution buffers (phosphate buffered saline or maximum recovery diluent with and without polysorbate 80), agitation methods (vortexing, stomaching, shaking by hand or with glass beads) and recovery agar (selective or non-selective). Recovery was compared to swabbing, RODAC plates and dip slides. Survival of E. faecium during a cold industrial wash with and without detergent was compared between loose swatches and those enclosed within cloth bags. Results Recovery of all test species was significantly (p≤0.05) greater using elution methods than non-destructive methods, while RODAC plates and dip slides were unquantifiable at 108 CFU/ml. Recovery was not significantly different between elution buffers or recovery agar. Shaking by hand was generally marginally more precise and efficient in microbial recovery. E. faecium was significantly (p≤0.05) reduced by industrial laundering with and without detergent; there was no significant difference when enclosed in cloth bags. Conclusions Surface testing methods have limited sensitivity compared to elution methods, suggesting that destructive methods are most appropriate for hygiene monitoring of laundered healthcare textiles. Swatch testing is confounded by a loss of microorganisms to dilution and agitation in the wash; further tests need to be developed to monitor the kill of microorganisms in the wash in order to develop a standardised test methodology to be used throughout global industrial laundries.

Background: In the UK nurses’ uniforms are domestically laundered, posing a threat of cross contamination of healthcare-associated infections. The UK Department of Health recommends washing uniforms at 60ºC, however nurses most commonly wash them at 40ºC. Bacteria survive on textiles washed at low temperatures; 4.28-4.62 log10 Escherichia coli and Staphylococcus aureus survived washing at 40ºC and cross contaminated other textiles in the wash. Antimicrobial laundry supplements could sanitise textiles and limit cross-contamination. A supplement that deposits an antibacterial coating onto textiles could also reduce contamination between washes. This study aimed to investigate a silver-based antimicrobial textile coating product (Micro-Fresh 1911) as a dual-use antimicrobial laundry supplement and textile coating. Materials/methods: Polycotton inoculated with 108 CFU/mL E. coli or S. aureus (type and clinical isolates) were washed with 2% Micro-Fresh 1911 in a domestic washing machine (40°C) and surviving microorganisms enumerated. Washes were conducted with and without soiling and biological detergent. Control washes were water alone. The antimicrobial activity of polycotton washed with Micro-Fresh 1911 at 40°C was assessed against S. aureus and E. coli using ISO 20645 and ISO 20743 methods. Controls were polycotton washed in water and textile padded with Micro-Fresh 2611. Results: Washing with Micro-Fresh 1911 reduced E. coli and S. aureus by 7.14-8.08 log10. No cells were recovered from sterile textile, whereas washing with water alone reduced E. coli and S. aureus by 2.21-4.25 log10 and resulted in 3.13-4.01 log10 CFU cross-contamination. Combining Micro-Fresh 1911 with biological detergent reduced E. coli and S. aureus by 5.56-6.65 log10. Fabric washed with Micro-Fresh 1911 was antimicrobial against E. coli and S. aureus type and clinical isolates according to ISO 20645 and ISO 20743. The antimicrobial coating remained after washing the fabric in water once at 40°C and 73°C. Conclusions: Micro-Fresh 1911 exibits antimicrobial activity in a 40ºC domestic wash and deposits an antimicrobial layer onto polycotton. Micro-Fresh could be employed as an antimicrobial laundering product to reduce microbial contamination of healthcare laundry washed at low temperatures.