@article {901, title = {Impact of Sample Collection Order on the Diagnostic Performance of Metagenomic Deep Sequencing for Infectious Keratitis.}, journal = {Cornea}, volume = {41}, year = {2022}, month = {2022 Jan 01}, pages = {39-44}, abstract = {

PURPOSE: The purpose of this article was to evaluate the impact of sample collection order on the diagnostic yield of metagenomic deep sequencing (MDS) for determining the causative pathogen in infectious keratitis.

METHODS: We performed a cross-sectional diagnostic test evaluation among subjects with infectious keratitis at Aravind Eye Hospital in Madurai, India. All subjects underwent corneal scrapings of the affected eye to obtain potassium hydroxide smear, Gram stain, bacterial culture, and fungal culture, in this order. The order of MDS specimen collection relative to smear and culture samples was randomized and served as the primary predictor. Outcomes included the normalized copy number of pathogenic RNA detected by MDS, the proportion of MDS samples that were diagnostic, and the agreement of MDS results with cultures.

RESULTS: MDS samples from 46 subjects with corneal ulcers were evaluated. MDS was positive in 33 subjects (76\%) and had 74\% overall agreement with culture results. There was no association between order of MDS sample collection and normalized copy number of genetic material detected (P = 0.62) or the likelihood of MDS positivity (P = 0.46). However, the likelihood of agreement between MDS and cultures decreased when MDS corneal swabs were collected after other diagnostic corneal scrapings (P = 0.05).

CONCLUSIONS: The overall yield of MDS for detecting the cause of infectious keratitis was not affected by sample collection order. However, diagnostic agreement between MDS and cultures decreased when MDS samples were collected after other specimens. Additional investigation is warranted to determine whether this represents increased sensitivity of MDS compared with cultures or higher susceptibility to contaminants.

}, keywords = {Adolescent, Adult, Aged, Aged, 80 and over, Bacteria, Cornea, Cross-Sectional Studies, DNA, Bacterial, DNA, Fungal, Eye Infections, Bacterial, Eye Infections, Fungal, Female, Fungi, High-Throughput Nucleotide Sequencing, Humans, Keratitis, Male, Metagenome, Middle Aged, Specimen Handling, Young Adult}, issn = {1536-4798}, doi = {10.1097/ICO.0000000000002766}, author = {Redd, Travis K and Lalitha, Prajna and Prajna, N Venkatesh and Sikha, Misra and Gunasekaran, Rameshkumar and Hinterwirth, Armin and Chen, Cindi and Zhong, Lina and Liu, Zijun and Lietman, Thomas M and Keenan, Jeremy D and Doan, Thuy and Seitzman, Gerami D} } @article {916, title = {Very late onset LASIK flap Acremonium fungal keratitis confirmed by metagenomic deep sequencing.}, journal = {Am J Ophthalmol Case Rep}, volume = {25}, year = {2022}, month = {2022 Mar}, pages = {101294}, abstract = {

Purpose: To describe a unique case of LASIK flap fungal keratitis confirmed by next generation sequencing.

Observations: A 56-year-old female presented with refractory keratitis involving her LASIK flap 21 years after surgery. Confocal was positive for filamentous structures. The patient underwent immediate flap amputation followed by topical antifungal treatment. Corneal culture was positive for sp. Metagenomic deep sequencing confirmed as the primary source of infection and also identified as a likely contributor of a mixed fungal infection. Sequencing also identified hay as the likely source of the infection. Treatment resulted in eradication of the infection. The patient{\textquoteright}s final best corrected visual acuity was 20/30 with rigid contact lens overrefraction.

Conclusions: Metagenomic deep sequencing is a novel diagnostic tool that is increasingly being utilized for diagnosis of refractory keratitis. This case demonstrates the diagnostic potential of deep sequencing for identifying post-LASIK keratitis and reinforces the utility of LASIK flap amputation in the setting of tectonic flap instability due to keratolysis.

Importance: This case highlights several important clinical points for treating LASIK flap keratitis and highlights the emerging role metagenomic sequencing has in the diagnosis of infectious keratitis. This is first known case using next generation sequencing to diagnose a post-LASIK infectious keratitis.

}, issn = {2451-9936}, doi = {10.1016/j.ajoc.2022.101294}, author = {Greenwald, Miles F and Redd, Travis K and Doan, Thuy and McLeod, Stephen D and Seitzman, Gerami D} }