Domestic laundering of healthcare textiles: Disinfection efficacy and risks of antibiotic resistance transmission

Abstract

Hospital-acquired infections (HAIs) and antimicrobial resistance (AMR) are a major public health concern, with the evidence base for the potential role of textiles as fomites in microbial transmission growing. In the UK, domestic laundering machines (DLMs) are commonly used to clean healthcare worker uniforms, raising concerns about their effectiveness in microbial decontamination and role in AMR development. This study aimed to evaluate DLMs’ ability to decontaminate microorganisms and their potential impact on AMR. The performance of six DLMs was assessed using Enterococcus faecium bioindicators under various wash cycles and detergent conditions. Shotgun metagenomics was used to analyse the microbiome and resistome of DLMs. The minimum inhibitory concentrations of domestic detergents were determined for Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa, and detergent tolerance and antibiotic cross-resistance were assessed. Results showed only 50% (3/6) of DLMs achieved sufficient decontamination (≥5 log10 CFU reduction) at 60°C during full-length cycles, with rapid cycles performing inconsistently. Microbiome analysis revealed the presence of potentially pathogenic bacteria (e.g., Mycobacterium sp. Pseudomonas sp. and Acinetobacter sp.) and antibiotic resistance genes, including efflux pumps and target modification genes. Detergent tolerance assays showed increased bacterial tolerance to detergents, with cross-resistance to antibiotics observed in S. aureus and K. pneumoniae, including carbapenem and β-lactam groups. Whole genome sequencing identified mutations in genes encoding efflux pumps in S. aureus (MrgA) and K. pneumoniae (AcrB) after detergent exposure, which could impact efflux pump function. Findings suggest domestic laundering of healthcare uniforms may be insufficient for decontamination, posing risks for HAI transmission and AMR. Revising laundering guidelines to ensure effective DLM performance, detergent efficacy, and considering alternatives like onsite/industrial laundering are crucial to enhancing patient safety and controlling AMR in healthcare settings.