Conjunctival Microbiota And Blepharitis Symptom Scores In Patients With Ocular Rosacea

Investigation of the relationship between blepharitis related symptom scores, tear film functions, and conjunctival microbiota in patients with ocular rosacea (OR) compared to healthy controls was aimed.

Departments of ophthalmology, dermatology, and microbiology in a single tertiary care referral hospital (Basaksehir Cam and Sakura City Hospital)

Consecutive 33 eyes of 33 patients with OR who were admitted from the dermatology clinic and age- and gender-matched 30 healthy controls without any ocular pathology between July 2021 and February 2022 were included in the study. Tear breakup time (TBUT), Schirmer’s score and blepharitis symptom score (BLISS) were recorded for each patient. For the bacteriological examination, bacterial culture was obtained by inoculating the samples on chocolate agar, blood agar, and fluid thioglycollate medium. After 24–48 hours of incubation at 37⁰C, the growth of different colonies of bacteria was identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

Bacterial culture positivity was observed in 13 eyes (39.4%) in the OR patients and 10 eyes (33.3%) in the controls (p=0.794). Patients with OR showed worse TBUT and Schirmer’s scores, and higher BLISS scores compared to the controls (p=0.005, p=0.007, and p=0.001, respectively). OR patients with conjunctival culture-positive results showed higher BLISS scores (8.0±4.7) compared to those with negative results (4.7±2.3; p<0.001). However, a similar significant difference in BLISS scores was not observed in the controls with culture-positive results (4.0±2.5) compared to those with negative results (3.8±2.2; p=0.606). The most frequent bacteria was Micrococcus luteus (18.2%) in OR patients and Staphylococcus epidermidis (20%) in the controls.

This pilot study showed that patients with OR had similar conjunctival culture positivity compared to healthy controls. However, the observation of different dominant bacterial species in conjunctival microbiota and the observation of worse BLISS scores in OR patients with positive culture without any worsened BLISS scores in healthy controls with positive culture results might suggest a potential role of conjunctival microbiota in the pathogenesis of OR. Further studies utilizing 16S rRNA-based identification methods may provide a better understanding of the role of conjunctival microbiota in the pathogenesis of OR.