This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
[{'content': 'Penicillin is effective against: \nSelect and explain. \nA. Neisseria meningitidis, B. Neisseria gonorrhoeae, C. Treponema pallidum, D. All of the above', 'role': 'user'}, {'content': 'Answer: D \nExplanation: PENICILLIN-G (BENZYL PENICILLIN)\nAntibacterial spectrum: PnG is a narrow spectrum antibiotic; activity is limited primarily to gram-positive bacteria, few gram negative ones and anaerobes.\nCocci: Streptococci (except viridans, group D or enterococci) are highly sensitive, so are many pneumococci. Staph.\xa0aureus, though originally very sensitive, has acquired resistance to such an extent that it must be counted out of PnG spectrum. Gram negative cocci-Neisseria gonorrhoeae and N. meningitidis are susceptible to PnG, though increasing number of gonococci have developed partial and other\xa0high degree resistance.\nBacilli: Gram-positive bacilli – majority of B. anthracis, Corynebacterium diphtheriae, and practically all Clostridia (tetani and others), listeria are highly sensitive, so are spirochetes (Treponema pallidum, Leptospira, and others), but Bacteroides fragilis is largely resistant.\nActinomyces israelii is only moderately sensitive.\nMajority of aerobic gram-negative bacilli, Mycobacterium tuberculosis, rickettsiae, chlamydiae, protozoa, fungi and viruses are totally insensitive to PnG.\nGonorrhea: PnG has become unreliable for the treatment of gonorrhoea.\nSyphilis: T. pallidum has not shown any resistance and PnG is the drug of choice. Early and latent syphilis is treated either with daily i.m.\xa0injection of 1.2 MU of procaine penicillin for 10 days or with 1-3 weekly doses of 2.4\xa0MU benzathine penicillin. For late syphilis, benzathine penicillin 2.4 MU weekly for 4 weeks is recommended. Cardiovascular and neurosyphilis requires sod. PnG 5 MU i.m 6 hourly for 10-14 days followed by the above regimen.\nReference: Essentials of Medical Pharmacology Eighth Edition KD\xa0TRIPATHI\xa0 page no 768,770', 'role': 'assistant'}]