Which organism is most likely identified by Gram-negative diplococci in ocular specimens causing conjunctivitis?

• A. Neisseria gonorrhoeae
• B. Moraxella catarrhalis
• C. Haemophilus influenzae
• D. Chlamydia trachomatis

Answer: (A)

Gram-negative diplococci in an eye discharge point to Neisseria gonorrhoeae. This organism is the classic cause of hyperacute conjunctivitis with copious purulent discharge, and its Gram stain appearance—Gram-negative cocci in pairs often seen inside neutrophils—strongly suggests gonococcal infection. Culture on chocolate or Thayer-Martin media can confirm and guide urgent treatment, since gonococcal conjunctivitis can rapidly threaten the cornea and vision. Other organisms listed don’t typically present as Gram-negative diplococci on a standard smear: Haemophilus influenzae are Gram-negative coccobacilli; Moraxella catarrhalis can look like diplococci but is less characteristically linked to this presentation; Chlamydia trachomatis isn’t visible as Gram-negative diplococci because it is an intracellular organism requiring special testing.