Final answer:
The two diseases that should be of concern are gonorrhea and nongonococcal urethritis (NGU). Gonorrhea can be treated with antibiotics, while NGU is treated with tetracyclines and azithromycin.
Step-by-step explanation:
The two diseases that should be of concern in this case are gonorrhea and nongonococcal urethritis (NGU). The symptoms of dysuria and milky penile discharge, along with the presence of gram-negative diplococci in the urine, are indicative of these diseases.
Gonorrhea can be treated with antibiotics, but it is important to note that some strains have developed resistance to certain drugs. The recommended treatment is a combination regimen of ceftriaxone and azithromycin to cover for potential co-infection with C. trachomatis. It is also important to treat sexual partners to prevent reinfection and further spread of the infection.
NGU, on the other hand, is unrelated to gonorrhea and can be treated with tetracyclines (such as doxycycline) and azithromycin. Erythromycin is an alternative option. It is crucial to provide treatment for both diseases to alleviate symptoms and prevent complications.