Quantitative Analysis of the Bacteria in Blepharitis With Demodex Infestation

Abstract

Bacterial infection or Demodex infestation has been reported to contribute to chronic blepharitis. The association between Demodex mites and bacterial flora in this disease remains to be elucidated. Fifty-six consecutive patients diagnosed with chronic blepharitis and 46 healthy volunteers were recruited for this study. Using specimens of three epilated eyelashes and lid margin swabs, Demodex were identified microscopically and bacteria were determined by cultures, followed by colony counting and mass spectrometry. We found 191 Demodex mites, 161 D. folliculorum and 30 D. brevis, in 45 patients. Correspondingly, 101 Demodex, 63 D. folliculorum and 38 D. brevis, were found in 21 controls (p < 0.05, both). Bacterial culture-positivity was obtained in samples (eyelashes, lid margins, or both) from 54 patients and in eyelashes from 37 controls. The total colony counts and the incidences and colony counts of Propinibacterium acnes and Staphylococcus aureus from patients’ eyelashes were significantly higher than that of the controls. Furthermore, bacterial colony counts in blepharitis patients’ eyelashes with D. folliculorum were higher than that of controls with D. folliculorum (p < 0.01). Similarly, P. acnes colonies increased significantly in patients’ eyelashes with D. folliculorum (p < 0.05). These results suggest that D. folliculorum and P. acnes have a role in the occurrence of the chronic blepharitis. Further studies are required to reveal the relationship between these two organisms in blepharitis.

Association Between Demodex Infestation and Ocular Surface Microbiota in Patients With Demodex Blepharitis

“…The most prevalent microbes on the ocular surface were similar to the skin flora. Previous studies reported that mixed skin microbial flora, including P. acnes , were found in blepharitis patients and healthy controls, but Staphylococcus and other skin microbial flora were not found in healthy controls ( 17 ). Lee et al reported that the relative abundances of Streptophyta, Corynebacterium , and Enhydrobacter were higher on the ocular surfaces of subjects with blepharitis ( n = 7) than in healthy subjects ( 16 ).…”

“…Thorough understanding of the characteristics of ocular microbial community associated with demodex is essential for the pathogenesis, prevention, and treatment of blepharitis. Zhu et al showed that the total colony counts from blepharitis patients' eyelashes were significantly higher than that of the healthy controls ( 17 ). Because bacterial culture methods have limitations in bacterial identification, we compared the conjunctival sac bacterial microbiota between subjects with and without demodex blepharitis using 16S rRNA gene sequencing in this study.…”

“…However, the correlation between demodex and ocular microbial community remains unclear ( 16 ). With the traditional cultivation, Propionibacterium acnes colonies increased significantly in eyelashes of demodex blepharitis patients ( D. folliculorum ), which laid a foundation for the study of demodex ( 17 ). More recently, Ocular bacterial communities have been studied with 16S rRNA gene sequencing in healthy subjects ( 18 ) and in patients with ocular diseases.…”

Demodex Folliculorum and Bacterial Co-Infection in Patients With Blepharitis

“…patients. Zhu et al [23] did not observe differences in colonies of S. aureus and S. epidermidis between Demodex spp. infected and uninfected patients.…”

“…promotes colonization of the conjunctival sac with microbiota. Zhu et al [23] found bacteria in 54 patients with blepharitis (45 of them were also infected with Demodex spp.) and 37 controls.…”