Which bacteria are responsible for causing pneumonia?

Correct Answer: D

Rationale: The correct answer is D (All of the above) because different bacteria can cause pneumonia. Streptococcus pneumoniae is the most common cause of community-acquired pneumonia. Mycobacterium tuberculosis causes tuberculosis, which can lead to pneumonia. Pseudomonas aeruginosa is a common cause of hospital-acquired pneumonia. Therefore, all three bacteria can be responsible for causing pneumonia in different contexts. Choices A, B, and C are incorrect because each bacterium individually can cause pneumonia, so selecting only one option would not cover the full spectrum of bacterial causes of pneumonia.

Correct Answer: C

Rationale: The correct answer is C (Both A and B) because both Clostridium botulinum and Bacillus anthracis are capable of producing spores. Spores are highly resistant structures that allow bacteria to survive harsh environmental conditions. Clostridium botulinum and Bacillus anthracis produce spores as a survival mechanism when conditions become unfavorable. Choice A (Clostridium botulinum) is incorrect because it only represents one of the bacteria capable of producing spores. Choice B (Bacillus anthracis) is also incorrect as it alone does not encompass all bacteria capable of producing spores. Choice D (None of the above) is incorrect as both bacteria mentioned can produce spores.

Correct Answer: B

Rationale: The correct answer is B: prions. Autoclaving, a method of sterilization using high pressure and steam, is effective at destroying most microorganisms including fungi, bacteria, viruses, and most bacterial spores due to denaturation of their proteins and nucleic acids. However, prions are highly resistant infectious proteins that are not easily eliminated by autoclaving. Prions can withstand high temperatures and pressure, making them a challenge to eradicate. Neurotoxins (A), protozoan cysts (C), and mycoplasmas (D) are susceptible to autoclaving and would be destroyed during the process.

Correct Answer: C

Rationale: The correct answer is C because bacteriocins are substances with protein nature, not polysaccharides. Bacteriocins are antimicrobial peptides that kill bacterial cells, mainly those of closely related species or other strains of the same species. Polysaccharides are not typically involved in bacteriocin activity. Therefore, option C is false. Options A, B, and D are true statements supported by the nature and function of bacteriocins.

Correct Answer: B

Rationale: The correct answer is B: Clostridium tetani. Endospores are formed by certain bacteria as a survival mechanism in harsh conditions. Clostridium species, including C. tetani, have the ability to form endospores. Staphylococcus aureus (A), Neisseria gonorrhoeae (C), and Escherichia coli (D) do not produce endospores. Staphylococcus aureus is a gram-positive cocci bacterium, Neisseria gonorrhoeae is a gram-negative diplococci bacterium, and Escherichia coli is a gram-negative rod-shaped bacterium. Therefore, the correct choice is Clostridium tetani as it is known for its ability to form endospores.

Correct Answer: B

Rationale: The correct answer is B: prostatitis. Prostatitis is the most common bacterial infection affecting the male reproductive system. It is characterized by inflammation of the prostate gland due to bacterial infection. Symptoms include pain in the pelvic area, difficulty urinating, and fever. Cystitis (A) is a bladder infection, not specific to the male reproductive system. Mastitis (C) is inflammation of the breast tissue, which is not related to the male reproductive system. Nephritis (D) is inflammation of the kidneys, which is also not specific to the male reproductive system.

Correct Answer: C

Rationale: Rationale: Both Clostridium botulinum and Clostridium tetani produce neurotoxins. Botulinum toxin affects the nervous system by blocking neurotransmitter release, causing paralysis. Tetanus toxin affects the nervous system by interfering with neurotransmitter release, leading to muscle stiffness and spasms. Therefore, Choice C is correct. Choices A and B alone are incorrect because they only mention one of the bacteria that produces a neurotoxin. Choice D is incorrect because both bacteria mentioned in Choices A and B produce neurotoxins.

Correct Answer: C

Rationale: Sterilization refers to the complete elimination of all microorganisms, including their spores, which are the most resistant form of microbial life. Spores have a tough outer coating that protects them from harsh conditions, making them more difficult to destroy compared to vegetative cells, viruses, and protozoa. Therefore, the correct answer is C because sterilization targets and eliminates all forms of microorganisms, including spores. Choices A, B, and D are incorrect because sterilization goes beyond just targeting vegetative cells, viruses, or protozoa; it aims to eliminate all microorganisms present.

Correct Answer: A

Rationale: The correct answer is A: Giardia lamblia. Giardia lamblia is a protozoan parasite that causes foul-smelling diarrhea with trophozoites having two nuclei and flagella in stool microscopy. The presence of flagella and two nuclei is characteristic of Giardia lamblia. Entamoeba histolytica (Choice B) causes amoebic dysentery with trophozoites containing ingested RBCs. Trichomonas vaginalis (Choice C) is a sexually transmitted protozoan causing vaginitis with a distinctive pear-shaped trophozoite. Balantidium coli (Choice D) is a ciliated protozoan causing diarrhea with trophozoites containing a single nucleus.