Posted: July 24th, 2017

A 30-year-old man comes to the clinic because of a painful ulcer on his penis for the past week. He has had multiple sexual partners, including commercial sex workers. Physical examination shows lymphadenopathy in the inguinal region and a 1-cm tender ulcer with no induration located on the frenulum. A culture of the ulcer grows colonies on supplemented chocolate agar. A Gram stain of the colonies shows gramnegative coccobacilli. Which of the following is the most likely causal organism?

A 30-year-old man comes to the clinic because
of a painful ulcer on his penis for the past week.
He has had multiple sexual partners, including
commercial sex workers. Physical examination
shows lymphadenopathy in the inguinal region
and a 1-cm tender ulcer with no induration
located on the frenulum. A culture of the ulcer
grows colonies on supplemented chocolate agar.
A Gram stain of the colonies shows gramnegative
coccobacilli. Which of the following is
the most likely causal organism?
(A) Haemophilus ducreyi
(B) Herpes simplex virus
(C) Neisseria gonorrhoeae
(D) Treponema pallidum
(E) Trichomonas vaginalis