Highlights
- •In built environments Legionella can establish a synergistic relationship with fungi.
- •Fungi can help in the dissemination of Legionella in indoor environments.
- •Legionella cells aerosolized with fungi are less prone to ultraviolet disinfection.
Background
The modern built environment (BE) design creates unique ecological niches ideal for
the survival and mutual interaction of microbial communities. This investigation focused
on the synergistic relations between Legionella and the fungal species commonly found in BEs and the impact of these synergistic
relationships on the survival and transmission of Legionella.
Methods
A field study was conducted to identify the types and concentrations of fungi in BEs.
The fungal isolates purified from BEs were cocultured with Legionella to study their synergistic association. Cocultured Legionella cells were aerosolized in an air-tight chamber to evaluate the efficacy of ultraviolet
(UV) to inactivate these cells.
Results
Aspergillus, Alternaria, and Cladosporium were the most common fungi detected in samples that tested positive for Legionella. After coculturing, Legionella cells were detected inside fungal hyphae. The microscopic observations of Legionella internalization in fungal hyphae were confirmed by molecular analyses. UV disinfection
of the aerosolized Legionella cells that were cocultured with fungi indicated that fungal spores and propagules
act as a shield against UV radiation. The shield effect of fungal spores on Legionella cells was quantified at >2.5 log10.
Conclusions
This study provides the first evidence, to our knowledge, of Legionella cell presence inside fungi detected in an indoor environment. This symbiotic relationship
with fungi results in longer survival of Legionella under ambient conditions and provides protection against UV rays.
Key Words
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Article Info
Footnotes
Funding/Support: Supported by EnviroPak and HKreation . Publication of this supplement is primarily supported by RB, Montvale, New Jersey , with additional support from MicroBioTest , a division of Microbac Laboratories, Inc., Sterling, Virginia. The City University of New York (CUNY) and the University of Ottawa, Ottawa, Canada, are academic sponsors. Editorial support was provided by Ashley O'Dunne, PhD; Shannon O'Sullivan, ELS; and Alanna Franchetti, ELS of Medergy (Yardley, PA), and funded by RB.
Conflicts of Interest: None to report.
Identification
Copyright
© 2016 Published by Elsevier Inc. on behalf of Association for Professionals in Infection Control and Epidemiology, Inc.
