An investigation of a laundry facility that services several Seattle-area hospitals suggests that soiled clinical linens may be a source of surface Clostridium difficile contamination. According to a paper published in FEMS Microbiology Letters (Clostridium difficile Environmental Contamination within a Clinical Laundry Facility in the USA), the study determined if C. difficile could be cultured from clinical laundry facility surfaces.

A total of 240 surface samples were collected from dirty areas, which handle soiled clinical linens, and from clean areas, which process and fold the clean linens, within the University of Washington Consolidated Laundry facility in 2015.

All samples were collected at a laundry facility in Seattle. This facility processes linens from six Seattle area hospitals, 30 local outpatient clinics and the Washington National Primate Research Centre. Each week about 300,000 pounds of laundry are processed. The facility is separated into two floors with the majority of the soiled linen handled on the second floor and the clean linen handled exclusively on the first floor.

All of the samples that tested positive were in areas where dirty linens are handled; no C. difficile contamination was found in areas where only clean laundry was handled.

Of the samples taken from surfaces in the dirty side of the laundry facility, 23% (25/120 samples) tested positive for C. difficile.

Only 2% (2/120 samples) of sampled surfaces from the clean side were positive for C. difficile.

The two surfaces that were positive for C. difficile both came from a small area where soiled linen is handled in small batches. While the area is distinct from where clean linen is dried, ironed, and folded, it is on the same floor as the clean side. This indicates that the dirty linens were the likely source of the environmental contamination in the laundry.

According to researchers, their data may be an underestimation of true prevalence and diversity of C. difficile on surfaces. The study is limited by the inherently poor recovery of microbes from environmental surfaces, difficulty in culturing C. difficile spores, differences in recommended incubation times and media used.

“This research supports the idea that its possible for the soiled hospital linens to contaminate the environment with C. difficile, which is the number one cause of hospital associated diarrhoea,” said study author Marilyn Roberts, PhD at the Department of Environmental and Occupational Health Sciences, University of Washington . “It's also extremely hard to remove from the environment. Due to this contamination, laundry facilities should be considered an extension of the healthcare environment when considering infection prevention and occupational health.”