Which bacteria are responsible for causing bacterial meningitis?

Correct Answer: D

Rationale: The correct answer is D, "All of the above." Bacterial meningitis can be caused by Neisseria meningitidis, Haemophilus influenzae, and Streptococcus pneumoniae. These bacteria are common pathogens associated with meningitis. Each of them can lead to serious infections in the brain and spinal cord. Neisseria meningitidis is known for causing meningococcal meningitis, Haemophilus influenzae is a common cause of H. influenzae meningitis, and Streptococcus pneumoniae is responsible for pneumococcal meningitis. Therefore, since all three bacteria can cause bacterial meningitis, the correct answer is D. Choices A, B, and C are incorrect because each of these bacteria individually can cause bacterial meningitis; it is not limited to just one specific type.

Correct Answer: B

Rationale: The correct answer is B: cell wall. Lysozyme is an enzyme that targets the cell wall of bacteria by breaking down the peptidoglycan layer, leading to bacterial cell lysis. This action disrupts the structural integrity of the bacteria, ultimately causing their death. Choices A, C, and D are incorrect because lysozyme does not target the cytoplasm, nucleus, or capsule of bacteria. The primary function of lysozyme is to act on the cell wall, making option B the correct answer in this context.

Correct Answer: C

Rationale: The correct answer is C: Bacteriophages are viruses that infect bacteria. Firstly, bacteriophages are viruses, not white blood cells or bacteria. They specifically target and infect bacteria, not fungi. This is known as a bacteriophage cycle where the virus injects its genetic material into the bacterial cell to replicate and eventually lyse the cell. This process is specific to bacteria and distinguishes bacteriophages from other microorganisms. Therefore, the correct answer is C as it accurately describes the nature and function of bacteriophages.

Correct Answer: D

Rationale: The correct answer is D. Escherichia coli, Salmonella enterica, and Pseudomonas aeruginosa all produce endotoxins that can lead to septic shock. Endotoxins are part of the outer membrane of Gram-negative bacteria and can trigger a systemic inflammatory response if released into the bloodstream. E. coli and Salmonella are common causes of bacterial infections that can lead to septic shock, while P. aeruginosa is a known opportunistic pathogen that can produce endotoxins. Therefore, all three bacteria can cause septic shock by releasing endotoxins. Choices A, B, and C are incorrect because each of these bacteria individually can produce endotoxins that contribute to the development of septic shock.

Correct Answer: A

Rationale: The correct answer is A: Mycobacterium leprae. This bacterium is responsible for causing leprosy. Mycobacterium leprae is a slow-growing bacterium that affects the skin and nerves, leading to the characteristic symptoms of leprosy. Neisseria gonorrhoeae is a sexually transmitted bacterium causing gonorrhea. Streptococcus pneumoniae causes pneumonia and other respiratory infections. Clostridium perfringens is associated with food poisoning and gas gangrene. Therefore, the correct answer is A because Mycobacterium leprae specifically causes leprosy, while the other choices are associated with different diseases.

Correct Answer: A

Rationale: The correct answer is A: Streptococcus pneumoniae. This bacterium is a common cause of pneumonia and is characterized by being Gram-positive cocci arranged in pairs with a capsule, as described in the question. The presence of a capsule is a key characteristic of Streptococcus pneumoniae, distinguishing it from the other choices. Staphylococcus aureus (B) is a Gram-positive cocci, but it typically forms clusters, not pairs. Klebsiella pneumoniae (C) is a Gram-negative rod, not a Gram-positive cocci. Enterococcus faecalis (D) is a Gram-positive cocci, but it does not typically present with a capsule in the same way Streptococcus pneumoniae does.

Correct Answer: D

Rationale: The correct answer is D: Primaquine. Primaquine is used for individual chemoprophylaxis of malaria caused by Plasmodium vivax and Plasmodium ovale. It is effective in preventing the relapse of these malaria species by eliminating the liver forms of the parasites. Chingamin (A) is not a commonly used drug for malaria prophylaxis. Pyrantel (B) is an anthelmintic drug used for treating parasitic worm infections, not malaria. Pyrimethamine (Chloridinum) (C) is primarily used in combination with sulfadoxine for treating uncomplicated malaria, not for chemoprophylaxis.

Correct Answer: B

Rationale: The correct answer is B: Corynebacterium diphtheriae. This bacterium produces a toxin that causes diphtheria. It forms a grayish membrane in the throat, leading to difficulty breathing. Bacillus anthracis (Choice A) causes anthrax, Streptococcus pneumoniae (Choice C) causes pneumonia, and Escherichia coli (Choice D) causes various infections but not diphtheria.

Correct Answer: A

Rationale: The correct answer is A: Sabouraud's peptone agar. This agar is specifically designed for the isolation of yeast and molds due to its low pH and high sugar content, creating an environment conducive for their growth. Yeast-like fungi thrive in this selective medium, while inhibiting the growth of bacteria and other contaminants. Summary: - Sabouraud's peptone agar is ideal for cultivating yeast-like fungi. - Endo agar is used for isolation of gram-negative bacteria, not fungi. - Milk-salt agar is used for lactobacilli and streptococci, not fungi. - Meat infusion agar is a general-purpose medium for cultivation of a wide range of microorganisms, not specifically for yeast-like fungi.