Final answer:
Gonorrhea, caused by the bacterium Neisseria gonorrhoeae, is the STD that presents with inflammation of the urethra, prostate, rectum, or pharynx.
Step-by-step explanation:
The sexually transmitted disease (STD) that is caused by a gram-negative bacterium and manifests as inflammation of the urethra, prostate, rectum, or pharynx is gonorrhea.
Gonorrhea is caused by the bacterium Neisseria gonorrhoeae, which can infect the reproductive and urinary tracts resulting in symptoms such as urethritis.
If left untreated, it can lead to more serious complications including epididymitis, salpingitis, and pelvic inflammatory disease, and in serious cases, it can spread to the bloodstream and infect other sites in the body.
Furthermore, untreated gonorrhea may lead to an increased risk of acquiring or transmitting HIV.