Ocular Surface Microbiota in Contact Lens Users and Contact-Lens-Associated Bacterial Keratitis.

Our objectives were to investigate whether the conjunctival microbiota is altered by contact lens wear and/or bacterial keratitis and to explore the hypothesis that commensals of conjunctival microbiota contribute to bacterial keratitis. Swab samples from both eyes were collected separately from the inferior fornix of the conjunctiva of non-contact-lens users (nparticipants = 28) and contact lens users (nparticipants = 26) and from patients with contact-lens-associated bacterial keratitis (nparticipants = 9). DNA from conjunctival swab samples was analyzed with 16S rRNA gene amplicon sequencing. Pathogens from the corneal infiltrates were identified by cultivation. In total, we identified 19 phyla and 283 genera; the four most abundant genera were Pseudomonas, Enhydrobacter, Staphylococcus, and Cutibacterium. Several pathogens related to bacterial keratitis were identified in the conjunctival microbiota of the whole study population, and the same bacteria were identified by both methods in the conjunctiva and cornea for four patients with contact-lens-associated bacterial keratitis. The overall conjunctival microbiota profile was not altered by contact lens wear or bacterial keratitis; thus, it does not appear to contribute to the development of bacterial keratitis in contact lens users. However, in some individuals, conjunctival microbiota may harbor opportunistic pathogens causing contact-lens-associated bacterial keratitis.

Ocular surface microbiota in patients with aqueous tear-deficient dry eye.

PURPOSE: An altered ocular surface microbiota may contribute to the pathophysiology of dry eye disease. The aim of the study was to explore potential differences in microbiota diversity and composition in aqueous tear-deficient dry eye (with and without ocular graft-versus-host disease) compared with controls. METHODS: Swab samples from the inferior fornix of the conjunctiva were obtained from patients with aqueous tear-deficient dry eye with and without ocular graft-versus-host disease (n = 18, n = 21, respectively) and controls (n = 28). Isolated bacterial DNA from swabs were analyzed with 16S rRNA gene amplicon sequencing. RESULTS: Decreased microbiota diversity was observed in patients with aqueous tear-deficient dry eye (p ≤ 0.003) who also showed a difference in microbiota composition compared with controls (p = 0.001). Although several genera were less abundant in aqueous tear-deficient dry eye, a minimal core ocular surface microbiota comprising five genera was shared by >75% of the study participants: Enhydrobacter, Brevibacterium, Staphylococcus, Streptococcus and Cutibacterium. Pseudomonas was identified as a bacterial biomarker for controls and Bacilli for patients with aqueous tear-deficient dry eye. CONCLUSIONS: Ocular surface microbiota in patients with aqueous tear-deficient dry eye was characterized by an aberrant microbiota composition in comparison to controls, with decreased diversity and reduced relative abundances of several genera. Additionally, a few genera were present in most of the study population, indicating that a minimal core ocular surface microbiota may exist.

Use of topical ocular antibiotics in young children: a Scandinavian drug utilization study.

PURPOSE: Acute infectious conjunctivitis is a common disease. While usually self-limiting, children often receive treatment to be accepted back into nursery, day care or school. We aimed to describe trends in the utilization of topical ocular antibiotics in young children aged 0-4 years in Denmark, Norway and Sweden. METHODS: Using individual-level data from the Danish National Prescription Registry (2000-2015), we provided detailed descriptions of treatment patterns at the individual level, stratified by age (0-1 years, 2-4 years) and antibiotic substance. Aggregate-level data for Danish, Norwegian and Swedish children (0-4 years) were obtained from publicly available data sources (2000-2016). RESULTS: We identified 107 581 Danish children aged 0-4 years receiving 271 980 treatment episodes. The incidence rate was relatively stable between 2000 and 2010 (on average, 637 and 283/1000 person-years for 0- to 1- and 2- to 4-year-olds, respectively), after which it dropped by 37% until 2015. In the aggregated data, a markedly higher use was seen in Denmark (211/1000 children in 2016) compared with Sweden (42) and Norway (151). The decrease from 2010 onwards was observed in all three countries. Chloramphenicol and fusidic acid were the most commonly used topical ocular antibiotics across Scandinavia. Tobramycin was rarely used in Norway and Sweden (≤1/1000 children in 2016) compared with Denmark (24/1000 children). CONCLUSION: Considerable variation is seen in the utilization of topical ocular antibiotics among children in Scandinavia, with Denmark having the highest use. Across the Scandinavian countries, however, a decline was noted from 2010 onwards.