Several days after an unprotected sexual encounter, a healthy 21-year-old male develops pain and pus on urination. A Gram stain reveals gram-negative diplococci. Which of the following structures is responsible for adherence of the offending microbe to the urethral mucosa?

Typical Neisseria are gram-negative diplococci. Neisseria gonorrhoeae contain pili, hair-like appendages that may be several micrometers long. They enhance attachment of the organism to mucous membranes, helping to make the organism more resistant to phagocytosis by WBCs. Gonococci isolated from clinical specimens produce small colonies containing piliated bacteria. Capsules appear to be less important in gonococcal infection than N. meningitidis infections. Flagella, peptidoglycan, LPS, and F pili do not significantly relate to pathogenesis, other than that LPS (endotoxin) release may become significant later in infection.N. gonorrhoeae showing pili and the three layers of the cell envelope