Nokea
Which of the following statements for genus Klebsiella is correct?
- A. They have real capsule and are non-motile
- B. They are obligatory anaerobic
- C. They form spores only under aerobic conditions
- D. None of the above
Correct Answer: A
Rationale: The correct answer is A because Klebsiella species have a real capsule, which is a distinguishing feature used for their identification. This capsule helps them evade the host immune response. Additionally, Klebsiella species are non-motile, meaning they do not possess flagella for movement. Choices B and C are incorrect because Klebsiella species are facultative anaerobes and do not form spores under any conditions. Choice D is also incorrect as option A is the correct statement for genus Klebsiella.
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Which of the following bacteria is responsible for causing the disease tetanus?
- A. Clostridium tetani
- B. Clostridium perfringens
- C. Streptococcus pyogenes
- D. Escherichia coli
Correct Answer: A
Rationale: The correct answer is A: Clostridium tetani. This bacterium is responsible for causing tetanus due to its production of tetanus toxin. Clostridium perfringens (B) causes gas gangrene, Streptococcus pyogenes (C) causes strep throat and skin infections, and Escherichia coli (D) is a common gut bacteria that can cause food poisoning but not tetanus.
The presence of E. Coli, Klebsiella pneumoniae and Pseudomonas aeruginosa in the pharynx is
- A. Part of the normal resident flora
- B. colonization
- C. both A and B
- D. none of the listed
Correct Answer: B
Rationale: The correct answer is B: colonization. E. Coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa in the pharynx indicate colonization rather than being part of the normal resident flora. Colonization refers to the presence of these bacteria on body surfaces without causing harm. They are not considered normal flora in the pharynx but rather transient or opportunistic pathogens. Choice A is incorrect because these bacteria are not part of the normal resident flora of the pharynx. Choice C is incorrect as it implies that these bacteria are both normal flora and colonization, which is not accurate. Choice D is incorrect as there is evidence of bacterial presence, indicating colonization.
Following treatment with a highly efficient anti-tuberculosis drug a 48-yearold female developed optic nerve neuritis, memory impairment, cramps. Which of these anti-TB drugs had the patient taken?
- A. Isoniazid
- B. PASA
- C. Rifampicin
- D. Ethambutol
Correct Answer: D
Rationale: Step 1: The symptoms of optic nerve neuritis, memory impairment, and cramps are indicative of ethambutol toxicity.
Step 2: Ethambutol is known to cause optic nerve toxicity leading to neuritis, as well as CNS toxicity causing memory impairment.
Step 3: Ethambutol can also lead to peripheral neuropathy manifesting as cramps.
Step 4: Isoniazid is associated with peripheral neuropathy and hepatotoxicity but not with optic nerve neuritis or memory impairment.
Step 5: PASA is not commonly used for tuberculosis treatment and does not cause the described symptoms.
Step 6: Rifampicin is known for hepatotoxicity and flu-like symptoms, but not specifically for optic nerve neuritis, memory impairment, or cramps.
Summary: Ethambutol is the correct answer due to its known side effects of optic nerve toxicity, CNS toxicity, and peripheral neuropathy, which align with the presented symptoms. Ison
A patient with acute food poisoning had fecal cultures grown on Endo agar, resulting in colorless colonies. What microorganism is most likely responsible?
- A. Salmonella
- B. Escherichia coli
- C. Staphylococcus
- D. Shigella
Correct Answer: A
Rationale: Step 1: Endo agar is a selective and differential media commonly used to isolate gram-negative bacteria.
Step 2: Colorless colonies on Endo agar indicate the absence of lactose fermentation.
Step 3: Salmonella is a gram-negative bacterium that does not ferment lactose, leading to colorless colonies on Endo agar.
Step 4: Therefore, the correct answer is A: Salmonella.
Summary:
B: Escherichia coli ferments lactose, producing pink colonies on Endo agar.
C: Staphylococcus is a gram-positive bacterium and would not grow on Endo agar.
D: Shigella is a gram-negative bacterium but ferments lactose, resulting in pink colonies on Endo agar.
What microorganisms were accounted for in this case?
- A. All bacteria that have grown on a nutrient medium
- B. Opportunistic pathogenic bacteria
- C. Enteropathogenic bacteria and viruses
- D. Colibacilli
Correct Answer: C
Rationale: The correct answer is C because the case specifically mentions "enteropathogenic bacteria and viruses," indicating a focus on these specific microorganisms. Choice A is too broad and includes all bacteria, which is not specified in the case. Choice B mentions opportunistic pathogenic bacteria, which are not necessarily relevant to the case. Choice D specifies colibacilli, which may or may not be relevant to the case, but it is not as specific as choice C which clearly matches the information provided in the case.