P-249. Diverse populations of viable pathogenic moulds and Candida, including C. auris, are commonly recovered from air samples at two tertiary care hospitals
Authors: Clancy Cornelius J , Driscoll Eileen , Cho Seong-Yoon , Wilkins Zachary , Hao Binghua , Cheng Shaoji , Sundermann Alexander , Snyder Graham M , Ayres Ashley , Nguyen Minh-Hong 
Published: January 2025

Abstract

Background
Airborne fungi are important nosocomial pathogens. However, there are scant data on populations of viable fungi in air from hospital environments.Table 1.Hospitals and units included in air sampling

Methods
We cultured air samples at least once/month beginning in May 2023 at 2 hospitals separated by 1.5 miles, 1 of which had new building construction [Table 1]. Air was collected with SASS 3100 (36,000 L/2 hrs onto dry filters) and SAS Super 100 (1,000 L directly onto MYE plates) samplers, at the following sites: Outside, lobby, nurse stations (NS) and rooms on units housing immunosuppressed hosts (protected (HEPA filter, positive pressure) and unprotected rooms). Processed filters (sonicated, un-sonicated) and plates were incubated at 30°C, and fungi identified by morphology and ITS sequencing.Table 2.Aspergillus positive air cultures at two hospitalsData from 2 hospitals are combined and presented as % of air samples with a given result.

Results
There was a hierarchy in air culture positivity for pathogenic moulds, which was similar at the 2 hospitals: outdoor cultures &gt; lobbies &gt; NS &gt; unprotected rooms &gt; protected rooms. The predominant fungus was Aspergillus fumigatus (68% and 6% of outdoor and protected room samples positive, respectively), followed by other Aspergillus spp [Table 2]. Other common moulds were Alternaria (48% outside +), Cladosporium (35% outside +), Fusarium (24% outside +) and Mucorales (17% outside +, including Rhizopus, Syncephalastrum racemosum and Mucor) [Table 3]. Candida was cultured at similar frequencies outside and inside hospitals ((overall + (range): 7% (3%-13%)); in rank order, spp. were C. glabrata (n=8), C. krusei (6), C. albicans (5), C. tropicalis (4), C. parapsilosis (3), C. auris (1). C. auris was recovered from a unit that was not known to house an infected pt.Table 3.Non-Aspergillus positive air cultures at two hospitalsData from 2 hospitals are combined and presented as % of air samples with a given result.

Conclusion
Potentially pathogenic fungi were commonly cultured from air samples inside and outside 2 hospitals in Pittsburgh, including within rooms housing immunosuppressed pts. Burdens were lower within hospitals than immediately outside. Fungi included moulds like Aspergillus spp., which are well-recognized airborne pathogens, and, surprisingly, Candida spp., which are not typically considered as such. Among the latter was C. auris, which was temporo-spatially distant from pts known to be infected at the hospitals. We are currently studying potential links between fungi recovered during surveillance and invasive fungal infections, including by whole genome sequencing.

Disclosures
Cornelius J. Clancy, MD, Cidara: Grant/Research Support|Gilead: Honoraria|Merck: Grant/Research Support|Scynexis: Advisor/Consultant|Shionogi: Advisor/Consultant|Venatorx: Advisor/Consultant Alexander Sundermann, DrPH, CIC, FAPIC, OpGen: Honoraria Graham M. Snyder, MD, SM, Infectious Diseases Connect: Advisor/Consultant