Abstract
Purpose :
Precision of pathogen identification in patients with endophthalmitis may be enhanced using metagenomic analysis. Metagenomic analysis was performed on vitreous samples from patients with suspected endophthalmitis to better understand the diagnostic utility and microbial diversity in patients with endophthalmitis.
Methods :
Metagenomic analysis was performed on 20 vitreous biopsies recovered from patients with suspected endophthalmitis who underwent diagnostic and therapeutic pars plana vitrectomies. The frequency of unique microbes (bacteria, virus, fungi, and protozoan) and bacteriophages were analyzed. All samples were also sent for laboratory culture, 6 of which a pathogen was identified in culture.
Results :
Metagenomic results from only 1 of the 6 culture-positive samples identified a microbe of the same genus as that identified on laboratory culture. A mean of 3.25 (SD 2.95) unique microbes were found in each of the 20 samples. Microbes consisted of 25 unique bacteria (mean per sample = 1.6 SD 1.6), 11 unique viruses (mean per sample = 1.5 SD 1.7), and 3 unique fungi (mean per sample = 0.2 SD 0.5). Anaerobic bacteria, excluding Cutibacterium (a commensal pathogen of the ocular surface), was found in 5 of the 14 culture-negative samples. 26 unique bacteriophages were also identified (mean per sample = 1.95 SD 1.8). The most prevalent microbes identified (prevalence of n≥3) were Streptococcus sp. (n=8 of 20), Cutibacterium sp. (n=4 of 20), Rhinovirus (n=5 of 20), and Rosellinia necatrix partitivirus (n=10 of 20). Common recurrent bacteriophages included Streptococcus phage 20617 (n=6 of 20), Burkholderia virus phiE125 (n=4 of 20) and Moineuvirus (n=3 of 20). Torque teno virus was detected in 1 sample.
Conclusions :
Metagenomic testing is a sensitive tool that can identify microbial elements not present on routine lab culture and may be a useful adjunct to the diagnosis and treatment of endophthalmitis. In the small sample size of the current study, there was minimal correlation between microbes identified by laboratory culture compared to those identified in the genomic analysis. Identification of several microbes and bacteriophages per sample may suggest that endophthalmitis is a multifactorial process influenced not just by one pathogen.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.