Comparison of the Vitreous Fluid Bacterial Microbiomes between Individuals with Post Fever Retinitis and Healthy Controls

Abstract

Ocular microbiome research has gained momentum in the recent past and has provided new insights into health and disease conditions. However, studies on sight threatening intraocular inflammatory diseases have remained untouched. In the present study, we attempted to identify the bacterial microbiome associated with post fever retinitis using a metagenomic sequencing approach. For this purpose, bacterial ocular microbiomes were generated from vitreous samples collected from control individuals (VC, n = 19) and individuals with post fever retinitis (PFR, n = 9), and analysed. The results revealed 18 discriminative genera in the microbiomes of the two cohorts out of which 16 genera were enriched in VC and the remaining two in PFR group. These discriminative genera were inferred to have antimicrobial, anti-inflammatory, and probiotic function. Only two pathogenic bacteria were differentially abundant in 20% of the PFR samples. PCoA and heatmap analysis showed that the vitreous microbiomes of VC and PFR formed two distinct clusters indicating dysbiosis in the vitreous bacterial microbiomes. Functional assignments and network analysis also revealed that the vitreous bacterial microbiomes in the control group exhibited more evenness in the bacterial diversity and several bacteria had antimicrobial function compared to the PFR group.

Intraocular Microbiome in Diabetes and Diabetic Retinopathy: A Pilot Study

“…Ours is a limited preliminary analysis, and it is too early to answer such questions. However, intraocular microbiota may prove to be a pathology-defining discovery for DR, like the earlier reports of intraocular microbiome (bacterial, fungal and viral) in the vitreous fluids of normal (control) and post-fever retinitis [1][2][3] from our group.…”

“…Considering the gut-retina axis, an end-organ dysbiosis is closer to the eye condition than other human micro-environments and may reflect long-term gut changes compared with short-term local volatilities in the gut. However, at present, our data on the intraocular microbiome (including ours) is only preliminary, and such a hypothesis should be considered appropriately [1][2][3].…”

Intraocular Viral Communities Associated With Post-fever Retinitis

“…The concomitant abundance of bacteriophages was significantly altered in the PFR group samples compared with the control group. Furthermore, we looked in the literature for the likely association of the EBV and discriminative bacterial genera, i.e., Tannerella and Pimelobacter, that was reported in our earlier publication in the PFR cohort (13). The direct association between Tannerella and Pimelobacter and EBV was not reported.…”

“…In our earlier study, using the next generation sequencing (NGS) approach, changes in bacterial microbiome and mycobiome associated with PFR were demonstrated. However, in particular, no ocular bacterial or fungal pathogen was identified in the PFR group compared with the control group (13,14). Viromes have been previously characterized on the surface of the skin (15), blood (16,17), breast milk (18), cerebrospinal fluids (19), oral cavity (20,21), lower gastrointestinal tract (22)(23)(24), respiratory tract (25), bladder (26), and vagina (27,28).…”