Preprint Article Version 1 Preserved in Portico This version is not peer-reviewed

One-Step Soft Agar Enrichment and Isolation of Human Lung Bacteria Inhibiting the Germination of Aspergillus fumigatus conidia

Fabio Palmieri
* ORCID logo ,
Margo Magnin
,
Jérémy Diserens
,
Manon Gresse
,
Eric Bernasconi
,
Julie Pernot
,
Apiha Shanmuganathan
,
Aurélien Trompette
,
Christophe Von Garnier
,
Thomas Junier
,
Samuel Neuenschwander
,
Saskia Bindschedler
,
Marco Pagni
,
Angela Koutsokera
,
Niki Ubags
* ,
Pilar Junier
*
Version 1 : Received: 30 May 2023 / Approved: 31 May 2023 / Online: 31 May 2023 (12:52:50 CEST)

How to cite: Palmieri, F.; Magnin, M.; Diserens, J.; Gresse, M.; Bernasconi, E.; Pernot, J.; Shanmuganathan, A.; Trompette, A.; Von Garnier, C.; Junier, T.; Neuenschwander, S.; Bindschedler, S.; Pagni, M.; Koutsokera, A.; Ubags, N.; Junier, P. One-Step Soft Agar Enrichment and Isolation of Human Lung Bacteria Inhibiting the Germination of Aspergillus fumigatus conidia. Preprints 2023, 2023052247. https://doi.org/10.20944/preprints202305.2247.v1 Palmieri, F.; Magnin, M.; Diserens, J.; Gresse, M.; Bernasconi, E.; Pernot, J.; Shanmuganathan, A.; Trompette, A.; Von Garnier, C.; Junier, T.; Neuenschwander, S.; Bindschedler, S.; Pagni, M.; Koutsokera, A.; Ubags, N.; Junier, P. One-Step Soft Agar Enrichment and Isolation of Human Lung Bacteria Inhibiting the Germination of Aspergillus fumigatus conidia. Preprints 2023, 2023052247. https://doi.org/10.20944/preprints202305.2247.v1

Abstract

Fungi of the genus Aspergillus are widespread in the environment where they produce large quantities of airborne conidia. Inhalation of Aspergillus spp. conidia in immunocompromised individuals can cause a wide spectrum of diseases, ranging from hypersensitivity responses to lethal invasive infections. Upon deposition in the lung epithelial surface, conidia encounter and interact with complex microbial communities that constitute the lung microbiota. The lung microbiota has been suggested to influence the establishment and growth of Aspergillus spp. in the human airways. However, the mechanisms underlying this interaction have not yet been sufficiently investigated. In this study, we aimed to evaluate the presence of commensal bacteria antagonistic to Aspergillus in the lung. To this end, we enriched and isolated bacterial strains able to inhibit the germination of conidia from bronchoalveolar lavage fluid (BALF) samples of lung transplant recipients. We used a novel enrichment method based on a soft agar overlay plate assay in which bacteria are directly in contact with conidia and for which inhibition can be readily observed during enrichment. We isolated a total of five bacterial strains, identified as Pseudomonas aeruginosa, and able to inhibit the germination and growth of Aspergillus fumigatus in a soft agar confrontation assay, as well as in a high-throughput multiplate assay. Moreover, we also showed a strong inhibition of A. fumigatus growth on Calu-3 cell culture monolayers. However, the isolated P. aeruginosa strains were shown to cause significant damage to the cell monolayers. Overall, we validated this novel one-step enrichment approach for the isolation of bacterial strains antagonistic to A. fumigatus from BALF samples. This opens up a new venue for targeted enrichment of antagonistic bacterial strains against specific fungal pathogens.

Keywords

lung microbiome; bronchoalveolar lavage fluid (BALF); antagonistic bacteria; biocontrol; Pseudomonas aeruginosa; aspergillosis

Subject

Biology and Life Sciences, Immunology and Microbiology

Copyright: This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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