endosymbiont bacteria and Mycotoxin Profiles in Fusarium Keratitis Isolates.

Abstract

Purpose : To highlight the presence and diversity of endosymbiotic bacterial species (microbiota) and mycotoxigenic profile of Fusarium clinical isolates.

Methods : We used a combination of PCR, 16S metagenomic sequencing (Ion Torrent) and Whole Genome Sequencing (CosmosID) to identify and compare the prevalence and diversity of bacterial-associated communities of 8 clinical fusarium isolates

Results : Seven of eight isolates belonged to the Fusarium solani complex including Fusarium keratoplasticum and one Fusarium oxysporum. Fumonisin mycotoxins were identified in eight of the 7 (87.5%) isolates. Trichothecenes were detected in only one of the 8 (12.5%) of the
Fusarium host-associated bacterial communities (7/8, 87.5%) were unique and included 179 bacterial species and 5 different phylotypes. Proteobacteria (59.2%) were the most common phylotype, followed by Actinobacteria (27.4%) and Firmicutes (10.6%). Bacteriodetes and Fusobacterial genomic signatures were documented in less than (<1%) of the isolates. No core microbiome was identified among this group. Ralstonia (25.7%, 6 patients), Propionibacterium (17.6%, 7 patients), Staphylococcus (9.0, 7 patients), and Pseudomonas (3.5%, 6 patients) had the highest relative abundance and documented in at least 75% of the samples. This group of bacteria were also documented at high frequency in the mycotoxin negative patient. Both Fumonisin and Trichothecene mycotoxins were documented in the microbiome negative clinical isolate.

Conclusions : Identifying fungal associated microbiota and their possible contribution to mycotoxin production and pathology may offer a unique opportunity to provide a more effective strategy for the management of fungal keratitis.

This is a 2020 ARVO Annual Meeting abstract.