Blepharitis is inflammation of which part of the eye?

• A. Streptococcus pneumoniae
• B. Staphylococcus epidermidis and Pseudomonas aeruginosa
• C. Haemophilus influenzae
• D. Staphylococcus aureus

Answer: (B)

Blepharitis is inflammation of the eyelid margin, usually driven by bacteria that colonize the lid skin. The eyelid flora is dominated by Staphylococcus species, especially Staphylococcus epidermidis, a common lid-margin commensal, and Staphylococcus aureus, which can contribute to more active infection. Pseudomonas aeruginosa can also appear in ocular infections, particularly in contact lens wearers, so this pair best captures the range of organisms that can underlie blepharitis. The other organisms listed are more characteristic of conjunctivitis or other eye infections rather than lid-margin inflammation, making the combination of Staphylococcus epidermidis and Pseudomonas aeruginosa the most fitting choice.