Abstract:

Objective To investigate the ocular surface microbial distribution characteristics of blepharitis patients, and analyze of the efficacy of antimicrobial therapy for blepharitis. Design Retrospective case series. Participants The study involved 101 patients with clinical diagnosis of blepharitis presented to Beijing Tongren Hospital between February 2015 to September 2015, and 85 normal controls. Methods Microbial samples of the ocular surface, including conjunctiva sac, eyelid, and Meibomian gland of blepharitis patients and normal controls were taken for culture and analyzed  for bacteria, anaerobic bacteria and fungi. The differences between the two groups were recorded analyzed. Furthermore, to analyze the effect of antimicrobial treatment, the blepharitis patients were divided into groups of non-antimicrobial group and antimicrobial group. The symptoms and ocular surface flora were compared before and two-weeks after treatment between the two groups. Main Outcome Measures Ocular bacterial test results, blood plate colony counting and blepharitis related symptoms and signs score. Results In blepharitis group, the Meibomian gland bacterial culture positive rate was 62%, while it was 53% in the control group (P=0.015). For anaerobic culture, the positive rate was significantly lower in blepharitis group and control group (19% versus 45%, P<0.001). Blepharitis and control group eyelid bacterial positive rate was 71% and 76% (P=0.533), conjunctival bacterial positive rates was 48% and 67% (P=0.062). The mean number of colonies on blood plate for eyelid, conjunctival and Meibomian gland was 15.78±5.25, 13.62±6.27 and 16.54±4.56 for blepharitis group respectively, which was significantly higher than the control group 6.13±3.40, 4.75±3.82 and 5.83±2.55 respectively, (all P<0.001). The proportion of Gram-positive cocci of the eyelid, conjunctival and Meibomian gland flora culture was 78.31%, 71.15% and 77.03% respectively, which was not significantly different from normal controls (76.71%, 82.14% and 76.74% respectively), blepharitis group of among Gram-positive cocci positive participants, the proportion of Staphylococcus positive rate was 81% and 88% for  conjunctival and Meibomian gland respectively for blepharitis patients, which was lower than the control group (96% and 100%, P=0.034 and 0.036 respectively). After two weeks of treatment or observation, the eyelid sterilization rate was 44% and 21% (P=0.034) for antimicrobial and non-antimicrobial treatment group respectively, and the difference between the two groups of symptoms and signs were also statistically significant (P=0.012). Conclusion The ocular surface bacterial positive rate in patients with blepharitis was not significantly different from control group, but the amount of bacteria carried on the ocular surface was higher in blepharitis patients, and the composition of Gram-positive cocci bacteria was different between the two groups. The amount of anaerobic bacteria contaminated Meibomian gland was lower in blepharitis patients than normal controls. Ocular antibiotic therapy can reduce the amount of bacteria carried, and improve patients' blepharitis related symptoms and signs. (Ophthalmol CHN, 2016, 25: 118-122)

Key words:  blepharitis；ocular bacterial flora；anaerobes, staphylococcus