The bacterium that causes gonorrhea is?

• A. Chlamydia trachomatis
• B. Treponema pallidum
• C. Haemophilus ducreyi
• D. Neisseria gonorrhoeae

Answer: (D)

Gonorrhea is caused by Neisseria gonorrhoeae. This organism is a Gram-negative diplococcus that typically infects mucosal surfaces such as the urethra, cervix, throat, and rectum and is transmitted through sexual contact. The other organisms listed cause different conditions: Chlamydia trachomatis leads to chlamydia, an intracellular bacterium often co-present with gonorrhea but not the gonorrheal agent itself; Treponema pallidum causes syphilis; Haemophilus ducreyi causes chancroid, which presents with painful ulcers rather than the discharge seen with gonorrhea. Knowing the correct causative agent helps guide testing and treatment, and clinicians often screen for both gonorrhea and chlamydia due to frequent co-infection.