Which of the following bacteria is commonly associated with food poisoning?

Correct Answer: D

Rationale: The correct answer is D: All of the above. Salmonella enterica, Clostridium botulinum, and Escherichia coli are all commonly associated with food poisoning. Salmonella causes symptoms like diarrhea, vomiting, and abdominal cramps. Clostridium botulinum produces a toxin that leads to symptoms like muscle weakness and paralysis. Escherichia coli can cause symptoms like severe stomach cramps, diarrhea (often bloody), and vomiting. Therefore, all three bacteria are known to cause food poisoning. The other choices are incorrect because each of the bacteria listed is associated with food poisoning.

Correct Answer: A

Rationale: The correct answer is A: Treponema pallidum. This bacterium is responsible for causing syphilis due to its unique spiral shape and ability to penetrate mucous membranes. It is transmitted through sexual contact or from mother to child during childbirth. Neisseria gonorrhoeae causes gonorrhea, Chlamydia trachomatis causes chlamydia, and Escherichia coli is a common bacterium found in the gut. Therefore, they are not responsible for syphilis.

Correct Answer: C

Rationale: Step-by-step rationale for why C is correct: 1. Immunomodulators regulate the immune response. 2. Gamma-interferon is a cytokine that enhances immune function. 3. It helps fight infections and regulate inflammation. 4. Pentaxim and Hexacima are combination vaccines. 5. Rifampin is an antibiotic, not an immunomodulator. Summary: - A and B are combination vaccines. - D is an antibiotic. - C is the correct answer as gamma-interferon is an immunomodulator that regulates the immune response.

Correct Answer: D

Rationale: The correct answer is D because the rubella virus has icosahedral symmetry, meaning it has a spherical shape with 20 equilateral triangular faces. This symmetry is common in many viruses and allows for efficient packaging of genetic material. Choice A is incorrect because the rubella virus does have glycoprotein spikes on its surface. These spikes help the virus attach to host cells. Choice B is incorrect because the rubella virus does have an envelope derived from the host cell membrane. This envelope plays a role in viral entry into host cells. Choice C is incorrect because the rubella virus is an ssRNA virus, not ssDNA. Its genetic material is single-stranded RNA, not DNA. In summary, the rubella virus has icosahedral symmetry and possesses glycoprotein spikes, an envelope, and ssRNA genetic material, making choices A, B, and C incorrect.

Correct Answer: A

Rationale: Step-by-step rationale: 1. Tularemia is caused by Francisella tularensis, a highly infectious bacterium. 2. Francisella tularensis is the only pathogen specifically known to cause tularemia. 3. The other choices (Bordetella pertussis, Brucella suis, Legionella sp.) are not associated with tularemia. 4. Therefore, the correct answer is A - Francisella tularensis.