Abstract
Purpose :
To investigate the profile of microorganisms in the storage media of human donor corneas using next generation sequencing (NGS).
Methods :
Seven samples from organ culture (OC) group (Cornea Max, Eurobio, France) with one control (sterile media without any cornea) and; seven samples from hypothermic storage group (Cornea Cold, Eurobio, France) with one control were used for this study. The corneas were placed in respective storage media for 14 days before collecting the samples. Storage media (2 mL) from each sample were collected in RNAase-free tubes and shipped for next generation sequencing (NGS). Simultaneously, another 1 mL media sample was used for conventional diagnostic method (CDM) using Bactec instruments.
Results :
In both, OC and hypothermic storage samples, the most abundant genera were Pseudomonas, Comamonas, Stenotrophomonas, Alcanivorax, Brevundimonasand Nitrobacter. Acidovorax, Acetobacterand Hydrogenophilus were detected mostly in the hypothermic storage group. The only fungal pathogens detected belonged to the genus Malassezia, and was abundant in both the storage conditions. CDM was negative for microorganism in all the samples. The positive results from the metagenomics group are assumed to be genomic material and not viable microbes.
Conclusions :
Using NGS, the media used to preserve human corneas has evidence of microorganisms not detected using CDM. It is unclear whether these microorganisms are not detected due to the inhibitory effect of the antimicrobials in the media, or whether these microorganisms are sequestered in the tissue from the antimicrobials or are non-viable. CDM may have to be performed to determine the presence of truly viable organisms along with metagenomic approach, which obtains full taxonomic and functional profiling of an organism. Metagenomics can serve as a full diagnostic approach especially to track infections caused by donated corneas. The antibiotic cocktail in the storage media for human donor corneas is efficient.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.