Survival of Clostridium difficile spores on cotton during healthcare laundering

The transmission of Clostridium difficile infection (CDI) is mediated by spores, which are highly resistant to heat and disinfectants. The healthcare laundry policy, Health Technical Memorandum 01-04 Decontamination of linen for health and social care, provides minimum disinfection conditions and microbiological standards for laundered linen: no bacteria on previously sterile de-sized textiles, >5 log(10) reduction of a thermotolerant species of bacteria and <100 cfu with no pathogenic bacteria on sampled linen. Quantification of the survival of spores, from hospital sheets (100% cotton) naturally contaminated with C. difficile spores were laundered in a washer extractor (WE) at a commercial laundry; they failed the microbiological standards. Similar results were achieved in a simulated healthcare WE cycle. The industrial detergent used failed the test for sporicidal activity (BS EN 13704), with a 2.81 log(10) reduction in spores. The method of recovering spores from swatches was important; in the presence of soiling, agitation by vortexing (4.48 log(10) cfu/25cm2) was more effective than stomaching (4.2 log(10) cfu/25cm2, p≤0.05). Spore adherence to cotton occurred over time, with 0% (0 hours) and 51% (24 hours) adherence; adherence decreased to 34% (24 hours) after exosporium removal, suggesting a role in spore adherence to cotton. The possibility cannot be discounted that low-level spore survival on processed linen may be contributing to environmental contamination and asymptomatic carriage.