A recent microbiological surveillance study found that >10% of linens tested positive for the fungi Mucorales at 20% of the hospitals included in the study. The data were published as a brief report in Clinical Infectious Diseases.
Mucormycosis is a life-threating condition caused by infection with Mucorales sp and is associated with mortality rates as high as 50%. Previous outbreaks have been linked with contaminated linens, prompting the investigation of linens from 15 transplant and cancer centers in the United States drawn largely from the Transplant Associated Infection Surveillance Network. Hospitals from each continental US time zone were represented in the survey.
Researchers established a dedicated team to meet healthcare linen delivery vehicles at each hospital between May and December 2017, and this team performed contact culturing on the linens immediately. Visual inspections noted that linens and laundry carts were unclean upon arrival at 33% and 20% of hospitals, respectively. These visual inspections showed evidence of hair, lint, insects, or other evidence of soiled cloth. Microbiologic testing found linens contaminated with Mucorales upon arrival at 47% of hospitals, and further testing found that at 20% of hospitals the linens were not sanitized of Mucorales. This result was based on the failure to attain a >90% culture negativity threshold. Findings at the individual centers showed that 0% to 24% of healthcare linens were culture positive for Mucorales sp. Factors that were significantly associated with Mucorales-contaminated linens were visibly soiled linens or carts and higher maximum temperatures and humidity in the vicinity of a laundry.
Longitudinal testing was performed at one center. In this test, linens did not meet the hygienically clean standard for Mucorales on 75% (6/8) of sampling dates between June 2016 and January 2017, and a median of 14% (range 3%-17%) of healthcare linens were contaminated. After this information was shared with the laundry and environmental remediation was enacted, all linens were hygienically clean for Mucorales, and no Mucorales were recovered on 83% (5/6) of subsequent sampling dates. On a single occasion, 2% (1/49) of linens were culture positive.
It should be noted that the study was not designed to determine the acquisition rate of fungii from hospital linens, but was rather a descriptive microbiologic study. No epidemiologic or clinical data were collected on mucormycosis or other fungal infections at the participating hospitals and linens were not tested for bacteria.
Follow-up studies will be needed to understand the significance of the findings, say investigators. Further, it is suggested that other priorities should include “developing practical and efficient microbiologic testing methods, criteria for interpreting culture results, and reasonable performance standards at laundries and in hospitals.” They also conclude that although it is impossible to eliminate infections from opportunistic environmental pathogens, “the objective for parties with a stake in this area is to work collaboratively to establish rational approaches to risk mitigation that optimize patient safety.”
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 [published online October 9, 2018]. Clin Infect Dis. doi: 10.1093/cid/ciy669