Abstract
Purpose :
Lacrimal canaliculitis is an uncommon inflammation of the lacrimal canaliculi usually resulting from canalicular concretions that can cause infections of the lacrimal canaliculi. Pathogen identification is important for proper diagnosis of lacrimal canaliculus. Recently, metagenomic analysis using next-generation sequencing has been used to detect pathogens directly from clinical samples. We report cases of successful pathogen detection by metagenomic analysis in patients with canalicular concretions.
Methods :
This study included 13 eyes of 12 patients (average age, 77.5 years) with lacrimal canaliculitis from which canalicular concretions were obtained from nine eyes using lacrimal endoscopy and four eyes using curettage between February 2015 and July 2017. The right upper lacrimal punctum was affected in five eyes, the left upper lacrimal punctum in four eyes, and the left lower lacrimal punctum in four eyes. The institutional review board approved the study. The shotgun sequencing library was prepared from the extracted DNA from the resected samples. We performed 150-base pair single-end metagenomic shotgun sequencing using the MiSeq platform (Illumina) and the human genome sequences were subtracted. The resulting sequences were subjected to a MegaBLAST search against the GenBank NT and Whole Genomic Shotgun databases followed by taxonomic classification using the MEGAN5.
Results :
Metagenomic analysis detected bacteria in all samples but no fungus or virus. The following anaerobic bacteria were found in the 13 eyes: Actinomyces genus in 13 (100%); Propionibacterium genus in 12 (92.3%); Parvimonas genus in 10 (76.9%); and Prevotella genus, Campylobacter genus, and Corynebacterium genus in seven (53.8%) eyes each. The following aerobic bacteria were found: Streptococcus genus in 13 (100%) and Streptomyces genus in 10 (76.9%).
Conclusions :
Pathogens were identified successfully using metagenomic analysis in patients with canalicular concretions. Both anaerobic and aerobic bacteria are found in the canalicular concretions.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.