By Stan Deresinski, MD, FACP, FIDSA
Clinical Professor of Medicine, Stanford University
Dr. Deresinski reports no financial relationships relevant to this field of study.
SYNOPSIS: Mucorales were found to commonly contaminate linen delivered to 15 transplant and cancer centers in the United States.
SOURCE: Sundermann AJ, Clancy CJ, Pasculle AW, et al. How clean is the linen at my hospital? The Mucorales on unclean linen discovery study of large United States transplant and cancer centers. Clin Infect Dis 2019;68:850-853.
In response to prior reports of hospital outbreaks of Mucorales infection associated with contaminated linen, Sundermann and colleagues set out to examine the frequency of such contamination at 15 U.S. transplant and cancer centers. Members of their group met linen delivery trucks at each hospital and immediately performed contact cultures. Healthcare linens (HCL) from a laundry were considered “hygienically clean” if Mucorales were not recovered from > 90% of items tested.
Visual contamination with lint, hair, insects, or other material was detected on five (33%) HCL on their arrival at the hospital, while this was true of three (20%) laundry carts. Mucorales was detected by culture of newly delivered HCL at seven (47%) hospitals. HCL were deemed not to be hygienically clean for these organisms based on the 90% rule at three (20%) hospitals. The proportion of contaminated HCL at individual hospitals ranged from none to 12/49 (24%). Culture positivity was associated with visually evident contamination and with high ambient relative humidities.
Repeat cultures over a seven-month period at a single hospital found that a median of 14% (range: 3-27%) of HCLs tested were positive. Other fungi recovered included, in decreasing order of frequency, Aspergillus, dematiaceous molds, and Fusarium. A marked decrease in frequency of Mucorales recovery was observed after routine cleaning of HCL carts and lint control measures were introduced.
At least three hospital outbreaks of Mucorales infections traced to contaminated HCL and/or carts have been reported, with infections involving the respiratory tract and skin. Nonetheless, as Sundermann and colleagues indicated in their discussion, the CDC has concluded that, while contaminated fabrics and textiles can be a source of infection, “the overall risk of disease transmission during the laundry process likely is negligible” and they do not recommend routine microbiological testing of HCL.
However, some third-party certification programs currently require performance of microbiological testing by hospital laundries. Whether the decrease in contamination was causally related to implementation of the measures described by Sundermann et al is uncertain, given the known variability of prevalence of Mucorales and other filamentous fungi.
California has taken a different approach, recently encoding in law (Title 22, Subsection 70825) a requirement that hospital linens be washed with an effective soap or detergent and rinsed thoroughly to remove soap or detergent and soil. Linens shall be exposed to water at a minimum temperature of 71 degrees C (160 degrees F) for at least 24 minutes during the washing process. Whether this would be effective in preventing outbreaks of fungal infections is uncertain.