Correct Answer: B

Rationale: The correct answer is B: Campylobacter jejuni. This bacteria is commonly associated with foodborne illnesses due to its presence in undercooked poultry and unpasteurized milk. Campylobacteriosis is a leading cause of bacterial gastroenteritis. Streptococcus pneumoniae (A) causes pneumonia, not foodborne illnesses. Mycobacterium tuberculosis (C) causes tuberculosis, not foodborne illnesses. Haemophilus influenzae (D) can cause respiratory infections but is not commonly associated with foodborne illnesses.

Correct Answer: C

Rationale: Step-by-step rationale: 1. Aspergillus flavus is a fungus known to produce aflatoxin. 2. Aflatoxin is a potent carcinogen found in contaminated food. 3. Candida albicans is a yeast species not associated with aflatoxin production. 4. Claviceps purpurea is a fungus that produces ergot alkaloids, not aflatoxin. 5. Staphylococcus aureus is a bacterium known for causing food poisoning, not aflatoxin production. Summary: Aspergillus flavus is the correct answer as it is the organism known to produce aflatoxin, a carcinogenic substance. Other choices are incorrect as they are not associated with aflatoxin production.

Correct Answer: A

Rationale: The correct answer is A: Carbenicillin disodium. Carbenicillin is a semisynthetic penicillin that has marked activity against Pseudomonas aeruginosa. This is due to its extended spectrum of activity and increased stability against beta-lactamases produced by Pseudomonas aeruginosa. Carbenicillin is commonly used to treat infections caused by this bacterium. Choice B: Benzylpenicillin (Penicillin G) has limited activity against Pseudomonas aeruginosa. Choice C: Methicillin is not effective against Pseudomonas aeruginosa. Choice D: Oxacillin also has limited activity against Pseudomonas aeruginosa. In summary, Carbenicillin is the correct choice due to its marked activity against Pseudomonas aeruginosa compared to the other penicillins listed.

Correct Answer: D

Rationale: The correct answer is D, "None of the above," because viruses like Parotitidis (mumps), Rubella, and Influenza A are not typically associated with reactivation under immunosuppressive therapy. Reactivation is more commonly seen in latent viruses like herpesviruses (e.g., herpes simplex, varicella-zoster), cytomegalovirus, and Epstein-Barr virus. These viruses can remain dormant in the body and reactivate when the immune system is compromised. Therefore, the correct answer is D, as the viruses mentioned in choices A, B, and C do not fit the criteria for reactivation under immunosuppressive therapy.

Correct Answer: C

Rationale: The correct answer is C because phagocytosis refers to the process where certain host cells engulf and destroy microorganisms. This is an essential mechanism of the immune system to eliminate pathogens. Choice A is incorrect because phagocytosis does not involve the use of antibiotics. Choice B is incorrect as it describes a different mechanism of action against bacteria. Choice D is incorrect because phagocytosis is a well-established biological process.