Final answer:
Syphilis is the STI that is successfully treated with penicillin. It is critical to treat syphilis early to prevent serious health complications.
Step-by-step explanation:
The sexually transmitted infection that is treated successfully with penicillin is syphilis. Penicillin, particularly long-acting benzathine penicillin G, is the recommended treatment and is highly effective in curing syphilis if administered early in the infection. A single intramuscular injection can cure primary, secondary, or early latent syphilis, while late latent or tertiary syphilis may require three doses at weekly intervals. Antibiotics, like penicillin, kill the syphilis bacteria and prevent further damage, but cannot repair damage that has already occurred. It is crucial to treat syphilis early to avoid serious complications, including damage to the heart, brain, and other organs, which can lead to death.
It's important to note that other options for syphilis treatment include tetracycline and doxycycline, especially for those who are allergic to penicillin. However, they are considered less effective. Furthermore, chlamydia is also a bacterial STI that is easily cured with antibiotics but not specifically with penicillin. Viral STIs like genital herpes and genital warts caused by HPV are not cured by antibiotics, though they can be managed with other treatments.