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Hospital Outbreak of Pulmonary and Cutaneous Zygomycosis due to Contaminated Linen Items From Substandard Laundry
Vincent C C Cheng1,2, Jonathan H K Chen1, Sally C Y Wong1
1Department of Microbiology, Queen Mary Hospital.
Background:
Healthcare laundry-related infection is rare, and pulmonary zygomycosis due to contaminated hospital linens has never been reported.
Methods:
We reported an outbreak investigation of zygomycosis in a university-affiliated teaching hospital. Air samplers, sponge swabs and Replicate Organism Detection and Counting (RODAC) contact plates were used for environmental sampling. The fungal isolates from clinical and environmental samples were identified by morphology, MALDI-TOF MS, and ITS1-5.8S-ITS2 rRNA gene cluster sequencing.
Results:
From 2 June 2015 to 18 July 2015, 6 immunosuppressed patients developed pulmonary (n = 4) and/or cutaneous (n = 3) infection by a spore-forming mold, Rhizopus microsporus, through direct inhalation and skin contact of contaminated linen items supplied by a designated laundry. Seventy (27.8%) of 252 freshly laundered clothing and 15 (3.4%) of 443 nonclothing laundered linen items (pillow case, bed sheet, draw sheet) were contaminated by R. microsporus, which was significantly higher than those from other hospital laundries (0%, n = 451; P < .001) supplying linen to hospitals with no cases of zygomycosis reported during the same period. The fungal isolates from patients and linens were phylogenetically related. In sum, 61% of environmental samples and 100% of air samples at the designated laundry were also positive for zygomycetes, suggesting heavy environmental contamination. RODAC contact plates revealed mean total viable bacteria counts of freshly laundered items (1028 ± 611 CFU/100 cm(2)) far exceeded the "hygienically clean" standard of 20 CFU/100 cm(2) set by the US healthcare textile certification requirement.
Conclusions:
Suboptimal conditions of washing, drying, and storage contributed to the massive linen contamination and the outbreak of zygomycosis.
Insights
An outbreak of zygomycosis, a rare fungal infection, occurred in a hospital due to contaminated linens from a specific laundry. Suboptimal laundry practices led to widespread contamination and patient infections, highlighting critical hygiene failures.
Area of Science:
- Medical Mycology
- Hospital Infection Control
- Environmental Microbiology
Background:
- Healthcare laundry is rarely associated with infections.
- Pulmonary zygomycosis from hospital linens has not been previously reported.
Purpose of the Study:
- To investigate an outbreak of zygomycosis in a teaching hospital.
- To identify the source and transmission routes of the fungal infection.
Main Methods:
- Environmental sampling using air samplers, sponge swabs, and RODAC plates.
- Identification of fungal isolates via morphology, MALDI-TOF MS, and gene sequencing.
- Phylogenetic analysis of clinical and environmental fungal isolates.
Main Results:
- Six immunosuppressed patients developed zygomycosis (pulmonary and/or cutaneous) linked to contaminated hospital linens.
- Rhizopus microsporus was identified as the causative agent, found on 27.8% of clothing and 3.4% of non-clothing linen items from a designated laundry.
- The designated laundry showed significantly higher contamination rates (P < .001) and heavy environmental contamination (61% of environmental, 100% of air samples positive).
- Bacterial counts on laundered items exceeded the 'hygienically clean' standard (20 CFU/100 cm²).
Conclusions:
- Suboptimal washing, drying, and storage conditions at the laundry facility led to massive linen contamination.
- This contamination resulted in an outbreak of zygomycosis among vulnerable patients.
- The findings underscore the importance of stringent laundry hygiene standards in healthcare settings.
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