[Bacterial profiles in conjunctival sac of middle-aged and elderly Qiang with dry eyes and normal eyes]

Abstract

Objective: To compare the bacteria profiles in conjunctival sac of Qiang aged 40 years and over between those with dry eyes and those with normal eyes.

Methods: This survey was undertaken with a standardized protocol in Beichuan county. Ophthalmological examinations were performed on 54 individuals with dry eyes (108 eyes) and 52 individuals with normal eyes (104 eyes). The secretion of the inferior palpebral conjunctival sac was embrocated and inoculated on blood plate for 48-72 hours. The bacteria was separated and identified.

Results: Positive cultural results were found in 57.4% (62/108) of dry eyes and 61.5% (64/104) of normal eyes. The difference was not statistically significant (P=0.540). No gender and occupational differences in positive cultural results were found (P>0.05). Both the dry eyes and normal eyes were dominated by Gram-positive bacteria, with corynebacterium, staphylococcus epidemids and sphingomonas paucimobilis as main bacteria. Samples taken from the dry eyes produced 73 strains bacteria, 52 (83.8%) with a single strain of bacteria and 10 (16.2%) with co-existed strains of bacteria. The samples taken from the normal eyes were more likely to have co-existed strains of bacteria (P=0.000). Of the 87 strains of bacteria, 64.0%, were single strain and 36.0% were coexisted strains. Fifteen species of bacteria were cultivated from the dry eyes, significantly less than the number of species (24) cultivated from the normal eyes (P=0.027).

Conclusion: There is no difference in bacterial positive rate in the conjunctival sac between dry eyes and normal eyes of Qiang aged 40 years and over. Gram-positive bacteria is the dominant bacteria. Normal eyes are more likely to have multiple coexisted bacteria compared with dry eyes.