Multiyear environmental surveillance in a pediatric teaching hospital: association between airborne mold spores and invasive mold infections.

Abstract

Background: The utility of routine environmental sampling to monitor the airborne fungal load (AFL) in healthcare settings is uncertain.

Methods: AFL was measured by monthly cultures at a tertiary-care pediatric hospital from November 2018 through October 2023 on eleven units caring for patients at risk for invasive mold infection (IMI). Surveillance for healthcare-associated IMI was conducted for all patients in the healthcare system using locally developed definitions for possible, probable, and definite hospital-onset infections. Poisson regression was used to analyze the association between AFL and monthly IMI rates.

Results: 78 cases of IMI were identified during the period of AFL monitoring. Of these, 51 infections were classified as healthcare-associated probable or proven IMI and were tested for association with AFL measurements. There was not a significant facility-wide association between the average monthly AFL and the overall IMI rate. On units where hematology/oncology patients were treated, however, an increase in average monthly local AFL for opportunistic fungal pathogens of 1 CFU/m³ was associated with a 1.48-fold increase in the IMI rate for these patients (95% CI 1.00-2.19, P = .05). The AFL for Aspergillus species on these units showed a particularly strong association with the hematology/oncology IMI rate (15.9-fold elevation for an increase of 1 CFU/m³ [95% CI 2.8-90.7, P = .002]). Neither hematology/oncology nor facility-wide IMI rates showed comparable associations with changes of the AFL in outdoor air.

Conclusions: Regular monitoring of AFL on targeted hospital units may identify periods when hematology/oncology patients are at increased risk for IMI.