Bacteriological profile of ocular surface flora in meibomian gland dysfunction

Purpose: To compare the bacteriological profile of meibomian gland secretion and conjunctival cul-de-sac in subjects with and without meibomian gland dysfunction (MGD).

Methods: This hospital-based study enrolled 201 eyes from 201 MGD patients and 84 eyes from 84 age- and gender-matched controls. Samples from the conjunctivae and meibomian gland secretion were obtained. Both aerobic and anaerobic cultures were performed. Differences in the culture-positivity and bacterial strains between two groups were compared.

Results: 36.9% and 10.7% of the control meibomian gland secretion recovered aerobes and anaerobes, respectively. A higher rate of aerobic (44.0%) and similar rate of anaerobic (10.7%) bacteria were isolated from the conjunctival cul-de-sac in these controls. Patients with MGD showed significantly higher positive culture rates from both the meibomian gland secretion (75.6% for aerobes and 34.3% for anaerobes) and conjunctival cul-de-sac (64.7% for aerobes and 30.8% for anaerobes). All p values were ≤ 0.001. In both groups and at either location, the predominant species isolated were Staphylococcus epidermidis (aerobes) and Propionibacterium acnes (anaerobes). Of note, the MGD patients harbor a much more complex bacterial profile than the controls.

Conclusion: Both aerobic and anaerobic bacteria can be isolated from the ocular surface of healthy subjects. Patients with MGD demonstrate significantly higher culture positivity and more complex bacterial profiles than the controls. Bacterial related cytotoxicity and/or inflammation may contribute to the pathological process of MGD.