title: The conjunctival microbiome in health and trachomatous disease: a case control study.
abstract: BACKGROUND
  Trachoma, caused by Chlamydia trachomatis, remains the world's leading infectious cause of blindness. Repeated ocular infection during childhood leads to scarring of the conjunctiva, in-turning of the eyelashes (trichiasis) and corneal opacity in later life. There is a growing body of evidence to suggest non-chlamydial bacteria are associated with clinical signs of trachoma, independent of C. trachomatis infection.
  
  
  METHODS
  We used deep sequencing of the V1-V3 region of the bacterial 16S rRNA gene to characterize the microbiome of the conjunctiva of 220 residents of The Gambia, 105 with healthy conjunctivae and 115 with clinical signs of trachoma in the absence of detectable C. trachomatis infection. Deep sequencing was carried out using the Roche-454 platform. Sequence data were processed and analyzed through a pipeline developed by the Human Microbiome Project.
  
  
  RESULTS
  The microbiome of healthy participants was influenced by age and season of sample collection with increased richness and diversity seen in younger participants and in samples collected during the dry season. Decreased diversity and an increased abundance of Corynebacterium and Streptococcus were seen in participants with conjunctival scarring compared to normal controls. Abundance of Corynebacterium was higher still in adults with scarring and trichiasis compared to adults with scarring only.
  
  
  CONCLUSIONS
  Our results indicate that changes in the conjunctival microbiome occur in trachomatous disease; whether these are a cause or a consequence is yet unknown.
authors.affiliation: The Genome Institute, Washington University, St Louis, MO 63108 USA ; Department of Pediatrics, Washington University School of Medicine, St Louis, MO 63130 USA.
authors.forename: Yanjiao
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Department of Clinical Research, London School of Hygiene and Tropical Medicine, London, WC1E 7HT UK.
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Holland
authors.affiliation: Disease Control and Elimination Theme, Medical Research Council Unit, Fajara, POB273 The Gambia.
authors.forename: Pateh
authors.initials: P
authors.lastname: Makalo
authors.affiliation: Disease Control and Elimination Theme, Medical Research Council Unit, Fajara, POB273 The Gambia.
authors.forename: Hassan
authors.initials: H
authors.lastname: Joof
authors.affiliation: Department of Clinical Research, London School of Hygiene and Tropical Medicine, London, WC1E 7HT UK.
authors.forename: Chrissy H
authors.initials: CH
authors.lastname: Roberts
authors.affiliation: Department of Clinical Research, London School of Hygiene and Tropical Medicine, London, WC1E 7HT UK.
authors.forename: David Cw
authors.initials: DC
authors.lastname: Mabey
authors.affiliation: Department of Clinical Research, London School of Hygiene and Tropical Medicine, London, WC1E 7HT UK.
authors.forename: Robin L
authors.initials: RL
authors.lastname: Bailey
authors.affiliation: Department of Clinical Research, London School of Hygiene and Tropical Medicine, London, WC1E 7HT UK.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Burton
authors.affiliation: The Genome Institute, Washington University, St Louis, MO 63108 USA ; The Jackson Laboratory for Genomic Medicine, Farmington, CT 06030 USA.
authors.forename: George M
authors.initials: GM
authors.lastname: Weinstock
authors.affiliation: Department of Clinical Research, London School of Hygiene and Tropical Medicine, London, WC1E 7HT UK ; Disease Control and Elimination Theme, Medical Research Council Unit, Fajara, POB273 The Gambia.
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Burr