Nokea
What is the primary function of bacterial capsules?
- A. Protein synthesis
- B. Aid in adhesion and protect against phagocytosis
- C. Facilitate motility
- D. Synthesize DNA
Correct Answer: B
Rationale: The primary function of bacterial capsules is to aid in adhesion and protect against phagocytosis. Capsules help bacteria adhere to surfaces and evade immune system detection by preventing phagocytosis. This is important for bacterial survival and colonization in host organisms. Choice A, protein synthesis, is incorrect as capsules do not directly participate in this process. Choice C, facilitate motility, is incorrect as capsules are not involved in bacterial movement. Choice D, synthesize DNA, is incorrect as capsules do not have a role in DNA synthesis. Thus, the correct answer is B.
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The patient 25 y.o. was admitted on the 1st day of the disease with complaints of double vision in the eyes, heavy breathing. The day before the patient ate homemade mushrooms. On objective examination: paleness, widened pupils, disorder of swallowing, bradycardia, constipation are marked. What is the diagnosis?
- A. Botulism
- B. Yersiniosis
- C. Leptospirosis
- D. Salmonellosis, gastrointestinal form
Correct Answer: A
Rationale: The correct answer is A: Botulism. Botulism is a rare but serious illness caused by a toxin produced by the bacterium Clostridium botulinum. In this case, the patient's symptoms align with botulism due to the ingestion of homemade mushrooms. The symptoms of double vision, heavy breathing, paleness, widened pupils, swallowing difficulties, bradycardia, and constipation are all classic signs of botulism poisoning. The toxin affects the nervous system and can lead to paralysis. The other choices (B: Yersiniosis, C: Leptospirosis, D: Salmonellosis) do not match the patient's symptoms and history of consuming mushrooms, making them incorrect.
The key diagnostic feature of Corynebacterium diphtheriae is:
- A. formation of spores
- B. presence of metachromatic granules
- C. production of coagulase
- D. beta-hemolysis on blood agar
Correct Answer: B
Rationale: The correct answer is B: presence of metachromatic granules. This is because Corynebacterium diphtheriae is known for containing metachromatic granules, which are characteristic of this species. These granules can be observed under a microscope and aid in the identification of the bacteria.
Explanation of other choices:
A: formation of spores - Corynebacterium diphtheriae does not form spores. Spore formation is more commonly seen in bacteria such as Bacillus and Clostridium species.
C: production of coagulase - Coagulase production is a characteristic of Staphylococcus aureus, not Corynebacterium diphtheriae.
D: beta-hemolysis on blood agar - Corynebacterium diphtheriae does not exhibit beta-hemolysis on blood agar. This type of hemolysis is more typical of Streptococcus pyogenes.
A patient presented with a painful, swollen lymph node, and bacteremia. A Gram-negative rod with a characteristic safety pin appearance was observed. What is the causative agent?
- A. Yersinia pestis
- B. Clostridium tetani
- C. Brucella melitensis
- D. Pasteurella multocida
Correct Answer: A
Rationale: Step 1: Gram-negative rod with safety pin appearance indicates bipolar staining.
Step 2: Yersinia pestis is a Gram-negative rod causing bubonic plague.
Step 3: Y. pestis has bipolar staining due to its unique F1 capsule.
Step 4: The swollen lymph node and bacteremia are consistent with bubonic plague.
Step 5: Therefore, the correct answer is A: Yersinia pestis.
Summary:
- B: Clostridium tetani causes tetanus, not characterized by a safety pin appearance.
- C: Brucella melitensis causes brucellosis, not characterized by a safety pin appearance.
- D: Pasteurella multocida causes animal bites infections, not characterized by a safety pin appearance.
Which bacteria is commonly associated with foodborne illnesses caused by contaminated water?
- A. Vibrio cholerae
- B. Clostridium difficile
- C. Mycobacterium tuberculosis
- D. Neisseria gonorrhoeae
Correct Answer: A
Rationale: The correct answer is A: Vibrio cholerae. This bacterium is commonly associated with foodborne illnesses caused by contaminated water due to its ability to survive and multiply in water sources. Vibrio cholerae causes cholera, a severe gastrointestinal infection transmitted through contaminated food and water. Clostridium difficile, Mycobacterium tuberculosis, and Neisseria gonorrhoeae are not typically associated with foodborne illnesses caused by contaminated water. Clostridium difficile causes gastrointestinal infections linked to antibiotic use, Mycobacterium tuberculosis causes tuberculosis through respiratory transmission, and Neisseria gonorrhoeae causes sexually transmitted infections.
While registering the child to the school Mantoux's test was made to define whether revaccination was needed test result is negative. What does this result of the test mean?
- A. Absence of antitoxic immunity to the tuberculosis
- B. Presence of antibodies for tubercle bacillus
- C. Absence of antibodies for tubercle bacillus
- D. Presence of cell immunity to the tuberculosis
Correct Answer: D
Rationale: Step 1: Mantoux test measures cell-mediated immunity response to tuberculosis.
Step 2: A negative result means no significant immune response to TB antigens.
Step 3: Option A is incorrect, as it refers to antitoxic immunity, not cell immunity.
Step 4: Option B is incorrect, as it mentions antibodies, not cell-mediated immunity.
Step 5: Option C is incorrect, as it states absence of antibodies, not cell immunity.
Step 6: Option D is correct as it directly correlates with the purpose of Mantoux test.