Review Question - QID 217295

This patient who presents with dysuria and purulent vaginal discharge most likely has Neisseria gonorrhea infection given the gram-negative diplococci seen on gram stain. This organism can be cultured using Thayer-Martin media.

Neisseria gonorrhea is a gram-negative diplococcus that commonly causes sexually transmitted infections. Patients will present with dysuria, purulent discharge, fever, prostatitis (men), endocervicitis (women), and urethritis. This organism is difficult to culture on normal media so Thayer-Martin media is used when this infection is suspected. Thayer-Martin is a selection media that contains vancomycin (which inhibits growth of gram-positive organisms), polymyxin (which inhibits growth of most gram-negative organisms), and nystatin (which inhibits growth of fungi). This combination of antimicrobial agents enables Neisseria gonorrhea to be one of the only organisms able to grow on this media.

Jacobs and Kraus compared the performance of Thayer-Martin media with translucent media alternatives for detecting Neisseria gonorrhea. They found that alternative selection media were equally effective and had marginally decreased rates of contaminants.

Figure/Illustration A is a gram stain showing clusters of "kidney-shaped" gram-negative diplococci (yellow circles) consistent with Neisseria species.

Incorrect Answers:
Answer 1: Chocolate agar is used to culture Haemophilus influenzae. This organism can present with otitis media, epiglottitis, cellulitis, and pneumonia but does not cause dysuria.

Answer 2: Eaton agar is used to culture Mycoplasma pneumoniae. This organism presents with subacute "walking" pneumonia rather than dysuria.

Answer 3: Löwenstein-Jensen media is used to culture Mycobacterium tuberculosis. This organism would present with fever, night sweats, and hemoptysis rather than dysuria.

Answer 4: MacConkey agar is used to culture lactose fermenting organisms such as Klebsiella pneumoniae. This organism would present with a productive cough and fever in patients who are at risk of aspiration (heavy alcohol users, patients with neuromuscular disorders). Klebsiella species can cause urinary tract infections, especially in older women, but do not cause cervicitis.

Bullet Summary:
Neisseria gonorrhea should be cultured on Thayer-Martin media, which contains vancomycin, polymyxin, and nystatin.