The conjunctival microbiome in health and trachomatous disease: a case control study

Abstract

BackgroundTrachoma, 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.MethodsWe 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.ResultsThe 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.ConclusionsOur results indicate that changes in the conjunctival microbiome occur in trachomatous disease; whether these are a cause or a consequence is yet unknown.Electronic supplementary materialThe online version of this article (doi:10.1186/s13073-014-0099-x) contains supplementary material, which is available to authorized users.

Azithromycin therapy during respiratory syncytial virus bronchiolitis: Upper airway microbiome alterations and subsequent recurrent wheeze

“…E4 PERMANOVA is a nonparametric method that tests whether the community structure is significantly different between groups. It uses a permutation test with pseudo F ratios to generate the P values.…”

“…At randomization, the airway microbiome community structure (bacterial composition and abundance), measured by permutational multivariate ANOVA test, 9 did not differ between the groups ( P = .7; Fig 1, A; and Fig E1 in this article's Online Repository at www.jacionline.org). The relative abundances of the most abundant bacterial genera are presented in Fig E1.…”

Glycerol Monolaurate Inhibits Lipase Production by Clinical Ocular Isolates Without Affecting Bacterial Cell Viability

“…Because more than 600 genera 43 have been identified from conjunctiva of healthy subjects, in vitro modeling of community interactions would be extremely complex. Whole community shotgun genomics or proteomics with in silico analysis of potential community interactions could offer a powerful alternative.…”

Development of a vaccine for Chlamydia trachomatis: challenges and current progress

“…50 However, in contrast to these findings, a more recent study of 105 Gambian participants with normal healthy conjunctivae has reported six genera found in at least 80% of participants, and these included Corynebacterium, Streptococcus, Propionibacterium, Staphylococcus, Bacillus, and Ralstonia, with Corynebacterium and Streptococcus higher in 115 participants with conjunctival scarring, and with Corynebacterium in even higher abundance in adults with clinical signs of scarring and trichiasis. 20 Despite the fact that indole-producing Corynebacterium is a predominant component of healthy eyes, this genus has also been reported in trachomatous eyes, 60 suggesting that changes in the normal conjunctival microbiome occur during trachomatous disease and also suggesting that non-chlamydial bacteria are associated with clinical signs of trachoma. 20 Interestingly, genital tract serovars of C. trachomatis can also cause inclusion conjunctivitis, a sexually transmitted disease that generally follows autoinoculation from contaminated …”

“…20 Despite the fact that indole-producing Corynebacterium is a predominant component of healthy eyes, this genus has also been reported in trachomatous eyes, 60 suggesting that changes in the normal conjunctival microbiome occur during trachomatous disease and also suggesting that non-chlamydial bacteria are associated with clinical signs of trachoma. 20 Interestingly, genital tract serovars of C. trachomatis can also cause inclusion conjunctivitis, a sexually transmitted disease that generally follows autoinoculation from contaminated …”