Investigation of a prolonged and large outbreak of healthcare-associated mucormycosis cases in an acute care hospital—Arkansas, June 2019–May 2021

Background Outbreaks of healthcare-associated mucormycosis (HCM), a life-threatening fungal infection, have been attributed to multiple sources, including contaminated healthcare linens. In 2020, staff at Hospital A in Arkansas alerted public health officials of a potential HCM outbreak. Methods We collected data on patients at Hospital A who had invasive mucormycosis during January 2017–June 2021 and calculated annual incidence of HCM (defined as mucormycosis diagnosed within ≥7 days after hospital admission). We performed targeted environmental assessments, including linen sampling at the hospital, to identify potential sources of infection. Results During the outbreak period (June 2019–June 2021), 16 patients had HCM; clinical features were similar between HCM patients and non-healthcare–associated mucormycosis patients. Hospital-wide HCM incidence (per 100,000 patient-days) increased from 0 in 2018 to 3 in 2019 and 6 in 2020. For the 16 HCM patients, the most common underlying medical conditions were hematologic malignancy (56%) and recent traumatic injury (38%); 38% of HCM patients died in-hospital. HCM cases were not epidemiologically linked by common procedures, products, units, or rooms. At Hospital A and its contracted offsite laundry provider, suboptimal handling of laundered linens and inadequate environmental controls to prevent mucormycete contamination were observed. We detected Rhizopus on nine (9%) of 98 linens sampled at the hospital, including on linens that had just arrived from the laundry facility. Conclusions We describe the largest single-center HCM outbreak reported to date. Our findings underscore the importance of hospital-based monitoring for HCM and increased attention to the safe handling of laundered linens.