A patient consulted a stomatologist about purulent inflammation of his gums. What drug will be the most effective if it is suspected that a causative agent is an anaerobe?

Correct Answer: A

Rationale: The correct answer is A: Metronidazole. Anaerobic bacteria are sensitive to metronidazole due to its mechanism of action targeting their DNA. Metronidazole is often the drug of choice for treating infections caused by anaerobic bacteria. Gentamicin, Oxacillin, and Co-trimoxazole are not effective against anaerobes. Gentamicin is an aminoglycoside mostly used for aerobic bacteria, Oxacillin is a beta-lactam antibiotic effective against gram-positive bacteria, and Co-trimoxazole is a combination of sulfamethoxazole and trimethoprim mainly used for urinary tract infections and some respiratory infections.

Correct Answer: D

Rationale: The correct answer is D: Clostridium. Clostridium bacteria produce the neurotoxin responsible for botulism. Clostridium botulinum is specifically known for causing this disease. Staphylococcus (A), Klebsiella (B), and Salmonella (C) do not produce the neurotoxin associated with botulism. Staphylococcus typically causes skin infections, Klebsiella is often associated with pneumonia and urinary tract infections, and Salmonella is known for causing food poisoning. Therefore, the correct answer is Clostridium due to its specific association with botulism.

Correct Answer: A

Rationale: The correct answer is A: Immobilization. This technique is called the Treponema pallidum immobilization (TPI) test, used to diagnose syphilis. The rationale is as follows: 1. TPI test detects antibodies that prevent the movement of treponemas, causing their death. 2. By immobilizing the treponemas, it indicates the presence of specific antibodies against syphilis. 3. This test is highly specific for syphilis diagnosis as it directly targets the causative agent. Other choices are incorrect: B: Complement binding - Not specific to syphilis, more commonly used for other diseases. C: Agglutination - Detects clumping of particles, not specific to treponemas or syphilis. D: Precipitation - Involves the formation of a solid, not directly related to treponema movement or death.

Correct Answer: B

Rationale: Protein A is a virulence factor specific to Staphylococcus aureus. This protein binds to the Fc region of immunoglobulins, inhibiting opsonization and phagocytosis. Therefore, the correct answer is B. Coagulase negative staphylococcus (choice A) does not produce Protein A. Micrococcus (choice C) is a different genus and does not possess Protein A. Choice D is incorrect because Protein A is indeed found in Staphylococcus aureus.

Correct Answer: C

Rationale: Rationale: Schizogony is the process in protozoans where multiple nuclear divisions occur before cell division. This results in the formation of multiple daughter cells. - A: Budding is a form of asexual reproduction where a new organism grows from an outgrowth on the parent. - B: Mitosis is a type of cell division that results in two identical daughter cells. - D: Fragmentation is a form of asexual reproduction where an organism breaks into fragments, each developing into a new organism.

Correct Answer: A

Rationale: The correct answer is A: Streptococcus pneumoniae. This bacterium is a Gram-positive cocci that often appear in pairs and can have a capsule. It is a common cause of sore throat and fever, known as streptococcal pharyngitis. Staphylococcus aureus (B) is a Gram-positive cocci but does not typically form pairs. Neisseria meningitidis (C) is a Gram-negative diplococcus and is more associated with meningitis. Klebsiella pneumoniae (D) is a Gram-negative rod and not typically associated with sore throat and fever.

Correct Answer: A

Rationale: Acyclovir is an antiviral drug used to treat herpes infections, not influenza. Tamiflu, Amantadine, and Relenza are all antiviral drugs commonly used to treat influenza. Acyclovir works by inhibiting the replication of herpes viruses, so it is not effective against the influenza virus. Therefore, the correct answer is A.

Correct Answer: A

Rationale: The correct answer is A: Nystatin. Nystatin is specifically used to treat intestinal candidiasis because it targets and eliminates the Candida species responsible for the infection. It is not absorbed systemically, acting only locally in the gastrointestinal tract. Griseofulvin (B) is mainly used to treat fungal skin infections, not intestinal candidiasis. Undecyne (C) is an antifungal agent used for skin infections, not for intestinal candidiasis. Amphotericin B (D) is a potent antifungal agent used for systemic fungal infections, not specifically for intestinal candidiasis.

Correct Answer: C

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.