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

## TL;DR

This study found that higher airborne mold spore levels in specific hospital units correlate with increased mold infections in high-risk patients.

## Contribution

The study demonstrates a unit-specific link between airborne mold spores and mold infections in hematology/oncology patients.

## Key findings

- An increase of 1 CFU/m3 in local airborne mold spores was associated with a 1.48-fold increase in mold infections among hematology/oncology patients.
- Aspergillus spores showed a 15.9-fold increase in infection risk per CFU/m3 in high-risk units.
- No significant association was found between outdoor air mold spores and hospital infections.

## Abstract

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

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.

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.

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