Demodex Folliculorum and Bacterial Co-Infection in Patients With Blepharitis

Abstract

Background Demodex mites are obligate ectoparasites found in the pilosebaceous follicle and sebaceous gland of many mammals. The aim of the study was to examine prevalence of bacterial infection in Demodex folliculorum infected patients with blepharitis. Methods The study included patients with a diagnosis of blepharitis with D. folliculorum (n=128) and healthy volunteers (n=103). Patients were questioned about their age, sex, social habits, and literacy status and per capita income. The examination consisted of examining the vision of the patient with and without ocular correction, tonus in both eyes and a careful examination of the anterior segment of both eyes. The bacterial culture of the conjunctival sac was obtained by inoculating the samples on Columbia agar with 5% sheep blood and identified based on morphological characteristics and stained by the Gram method. Species identification was performed by coagulase test or VITEK Compact. ResultsPhysiological flora was found in 8.7% participants from uninfected and all infected with D. folliculorum patients. We isolated Staphylococcus aureus, Acinetobacter baumannii, Streptococcus pneumoniae, Klebsiella oxytoca, and Bacillus spp. in the conjunctival sac only in patients infected with D. folliculorum. In patients with D. folliculorum infection mean intraocular pressure and visual acuity were lower than in uninfected participants. ConclusionsPatients infected with D. folliculorum should also undergo microbiological examination of conjunctival swabs. The treatment of each patient should be individualized, adapted to the clinical condition, and in cases of bacterial co-infection.