Infections of Legionella pneumophila are treated with:

Correct Answer: C

Rationale: The correct answer is C: Macrolides or fluoroquinolones. Legionella pneumophila is a bacterium that causes Legionnaires' disease, a severe form of pneumonia. Macrolides (like azithromycin) and fluoroquinolones (like levofloxacin) are the recommended first-line treatments due to their ability to penetrate into lung tissues where Legionella infects. Penicillins and cephalosporins (choice A) are not effective against Legionella as it is intracellular and resistant to these antibiotics. Ethambutol and isoniazid (choice B) are used to treat tuberculosis, not Legionella infections. Second and third generation cephalosporins (choice D) are also not effective against Legionella. Therefore, the best choice for treating Legionella pneumophila infections is macrolides or fluoroquinolones.

Correct Answer: A

Rationale: Rationale: The correct answer is Amebiasis (choice A) because the patient's symptoms of acute gastrointestinal disorders and prolonged stay in an African country suggest exposure to Entamoeba histolytica, the causative agent of amebiasis. This protozoal infection commonly occurs in tropical regions, including Africa. Trypanosomosis (choice B) is caused by Trypanosoma species transmitted by tsetse flies, primarily found in sub-Saharan Africa. Leishmaniasis (choice C) is transmitted by sandflies and presents with skin lesions or visceral involvement, not acute gastrointestinal symptoms. Malaria (choice D) is caused by Plasmodium parasites transmitted by mosquitoes and typically presents with fever, not acute gastrointestinal disorders. Therefore, choices B, C, and D are incorrect based on the patient's clinical presentation and travel history.

Correct Answer: D

Rationale: The correct answer is D, "All of the above." Clostridium botulinum produces botulinum toxin causing botulism, Vibrio cholerae produces cholera toxin leading to severe diarrhea, and certain strains of Escherichia coli produce toxins causing gastrointestinal illness. Therefore, all three bacteria are known for producing toxins that can cause severe gastrointestinal illness. Choices A, B, and C individually represent bacteria known for producing toxins that can cause severe gastrointestinal illness, making them incorrect individual choices.

Correct Answer: C

Rationale: Rifampicin is the correct answer because it is a first-line antibiotic for treating pulmonary tuberculosis. It has excellent bactericidal activity and penetrates well into lung tissues where the infection is located. Rifampicin is also known for preventing the development of resistance. Tetracycline (A) and Furasolidone (B) are not commonly used for tuberculosis treatment. Bactrim (D) is a combination of sulfamethoxazole and trimethoprim, not effective for tuberculosis treatment.

Correct Answer: A

Rationale: The correct answer is A: Ziehl-Neelsen staining method was applied. 1. Ziehl's solution is used as a primary stain in Ziehl-Neelsen staining for acid-fast organisms like Mycobacterium tuberculosis. 2. Sulfuric acid is used as a decolorizer to remove excess stain. 3. Methylene blue is not part of the Ziehl-Neelsen staining method. 4. Burri's, Gram's, and Peshkov's staining methods are not used for acid-fast staining.

Correct Answer: B

Rationale: The correct answer is B: Mycelium. Mycelium refers to the network of branching filaments that form the main body of a fungus. When fungi grow on solid media, they develop a visible mass of mycelium. Hyphae (A) are the individual filaments that make up mycelium. Spores (C) are reproductive cells produced by fungi. Columella (D) refers to a specialized structure found in some fungi but is not related to the colonies grown on solid media. Therefore, the correct term for the colonies of fungi on solid media is mycelium.

Correct Answer: B

Rationale: The correct answer is B: Personal eyewash. Personal eyewash is designed for immediate flushing until the victim reaches a more suitable safety unit. It provides a controlled flow of water to safely flush eyes while transporting the victim. The emergency shower (A) is meant for full-body coverage, not just for the eyes. Handheld drench hose (C) may not provide adequate flushing pressure. Combination unit (D) may not be easily portable for immediate use.

Correct Answer: D

Rationale: The correct answer is D because all three bacteria (Neisseria meningitidis, Haemophilus influenzae, and Streptococcus pneumoniae) can cause bacterial meningitis. Neisseria meningitidis is a common cause of meningococcal meningitis, Haemophilus influenzae can cause H. influenzae meningitis, and Streptococcus pneumoniae is a leading cause of pneumococcal meningitis. Therefore, all of the above choices are correct. The other choices are incorrect because each of the bacteria listed can independently cause bacterial meningitis, so none of them alone can be the sole correct answer.

Correct Answer: D

Rationale: The correct answer is D: BCG vaccination. BCG vaccination is recommended for individuals with a negative Mantoux test result, especially in countries where tuberculosis is prevalent. This vaccination can help provide protection against tuberculosis. Choice A is incorrect because repeating the Mantoux test in a month is unnecessary since the boy already had a negative reaction. Choice B is incorrect as serodiagnosis of tuberculosis is not the first-line approach for diagnosis, especially in this scenario. Choice C is incorrect because urgent isolation is not necessary based solely on the Mantoux test result. Isolation is typically reserved for individuals with active tuberculosis.