The combination of Demodex folliculorum and Aerobic Bacteria in the Etiopathogenesis of Chronic Blepharitis

Abstract Aims: This study was conducted to investigate the presence of thecombination of Demodex folliculorum and aerobic bacteria in patients with chronic blepharitis. Material and Methods: Seventy-one patients diagnosed with chronic blepharitis were evaluated for the presence of D. folliculorumby light microscope examination of samples prepared from eyelashes collected by eyelash epilation. Culture samples were also obtained from patients’ eyelid margins. Bacterial strainsamong the predominant bacterial colonies grown in cultures were identified using the BD Phoenix identification system (BD Diagnostic Systems, Sparks, USA). Patients were divided into two groups, Demodex-positive and Demodex-negative,and compared according to bacterial production and bacterial strains produced. Results: D. folliculorumwas identified in 42 (59.1%) patients. Comparison between Demodex-positive and -negative groups revealeda statistically significant increase in Demodex positivity with age.There was no significant relationship between gender and Demodex positivity.The Demodex-positive group showed a statistically significantly higher bacterial growth in the culture samples than the Demodex-negative group.Both groups exhibited a predominance ofStaphylococcus epidermidis. S.epidermidis (38.1% vs. 31.0%), Staphylococcus aureus (19.0% vs. 10.3%), and Corynebacterium spp.(16.7% vs. 6.9%) were detected at higher rates in the Demodex-positive group than in the Demodex-negative group. There was no statistically significant difference between both groups regarding the presence of these bacterial species. Conclusions: Patients with chronic blepharitis could have a mixedinfection site with the combination of D. folliculorumand aerobic bacteria found in the normal eyelid flora