Bacterial infection in scarring trachoma

Victor H. Hu, Patrick Massae, Helen A. Weiss, Caroline Chevallier, Jecinta J. Onyango, Isaac A. Afwamba, David C. W. Mabey, Robin L. Bailey and Matthew J. Burton (2010, IOVS)
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Purpose. To assess whether non-chlamydial bacterial infection is associated with trachomatous scarring in adults. Methods. Case-control study of 360 cases with trachomatous scarring but without trichiasis, and 360 controls without scarring. All participants underwent clinical examination and a swab was taken from the inferior conjunctival fornix. Samples were inoculated onto blood and chocolate agar later that day. Results. Bacterial isolates were identified in 54.0% of cases compared to 34.6% of controls (p<0.001). A multivariable logistic regression model adjusting for age and lack of education showed that scarring was associated with the presence of commensal organisms (OR=1.46, 95%CI 1.01-2.09) and was strongly associated with the presence of pathogenic organisms (OR=4.08, 95%CI 1.59-10.45). There was an increasing prevalence of all bacterial isolates with increasing severity of scarring (p-trend<0.001). Conclusion. Trachomatous scarring is strongly associated with non-chlamydial bacterial infection compared to controls. The role of such infection with regard to scarring progression needs to be investigated and may have important implications for trachoma control strategies and blindness prevention.