Introduction:

This webinar explores the role of domestic laundering machines (DLMs) in microbial decontamination and their potential contribution to hospital-acquired infections (HAIs) and antimicrobial resistance (AMR). In the UK & USA, it is common for healthcare worker uniforms to be washed at home, yet research indicates that many DLMs may not consistently eliminate harmful microorganisms.

The study assessed six domestic machines using Enterococcus faecium bioindicators under various wash cycles and detergent types. Only half of the rapid washes and a third of full washes achieved sufficient microbial reduction (≥5 log₁₀ CFU) at 60°C.

A key focus of this webinar is on the application of molecular techniques, especially shotgun metagenomics, to characterise the microbiome and resistome within DLMs. This revealed the presence of opportunistic pathogens such as Pseudomonas sp., Mycobacterium sp., and Acinetobacter sp., as well as resistance genes related to efflux pumps and target modification.

Further analysis demonstrated that detergent exposure increased bacterial tolerance and induced cross-resistance to critical antibiotics, including β-lactams and carbapenems. Whole genome sequencing identified mutations in efflux pump genes (MrgA, AcrB) following detergent stress.

These findings highlight the need to revisit healthcare uniform laundering guidelines, evaluate detergent efficacy, and consider centralised laundering to mitigate infection and resistance risks in healthcare environments.