Aerobic bacterial microbiota of the conjunctiva in diabetic patients with normal and altered glycated hemoglobin levels in two regions in Brazil

Abstract

Purpose: To study the aerobic bacterial microbiota of the conjunctiva in diabetic patients with regard to the management of diabetes, assessed using glycated hemoglobin levels. Methods: A cross-sectional study was conducted using conjunctival smears of diabetic patients from both sexes and with different ages, residing in two different Brazilian cities (Sorocaba and Rio Branco). A control group of non-diabetic patients was also included. The diabetic patients were considered to have controlled diabetes when their glycated hemoglobin level was ≤7% and blood glucose level was ≤126 mg/dL. Patients with non-controlled diabetes were those with glycated hemoglobin levels >7% and blood glucose levels >126 mg/dL. The samples obtained were inoculated in Brain-Heart Infusion broth and in culture media for aerobic bacteria (blood and chocolate agars); bacterial growth was evaluated in a microbiology laboratory. Results: A total of 120 eyes of 120 patients were included in the present study. The percentage of cultures in which bacterial growth was observed was greater in diabetic patients, although the difference was not statistically significant (p=0.103). There was a greater trend toward bacterial growth in the conjunctiva of diabetic patients with altered fasting blood glucose. There was no difference in the frequency of bacterial growth on the conjunctiva between diabetic patients with normal or altered glycated hemoglobin levels. In Sorocaba, conjunctival bacterial growth was similar to that observed in Rio Branco. The microorganism most frequently detected in the present study was Staphylococcus epidermidis, followed by Staphylococcus aureus, Proteus mirabilis, and Escherichia coli. Conclusions: There was no difference between diabetic patients with normal or altered glycated hemoglobin levels. The microorganisms found were similar to those found in studies investigating the conjunctival bacterial flora of diabetic and non-diabetic patients.

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