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Which bacteria is responsible for causing the disease known as tuberculosis?
- A. Mycobacterium leprae
- B. Mycobacterium tuberculosis
- C. Streptococcus pneumoniae
- D. Clostridium botulinum
Correct Answer: B
Rationale: The correct answer is B: Mycobacterium tuberculosis. This bacterium is responsible for causing tuberculosis as it specifically infects the lungs and can spread through the air. Mycobacterium leprae (choice A) causes leprosy, not tuberculosis. Streptococcus pneumoniae (choice C) is a common cause of pneumonia but not tuberculosis. Clostridium botulinum (choice D) causes botulism, a different disease unrelated to tuberculosis. Therefore, the unique characteristics and infection pattern of Mycobacterium tuberculosis make it the correct choice for the bacteria responsible for causing tuberculosis.
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Adenoviral infections are restricted only to the upper respiratory tract:
- A. TRUE
- B. FALSE
- C. Both answers can be correct depending on circumstances
- D. None of the above
Correct Answer: B
Rationale: The correct answer is B: FALSE. Adenoviral infections are not restricted only to the upper respiratory tract; they can also affect the gastrointestinal tract, eyes, and other organs. Adenoviruses are known to cause a wide range of illnesses beyond just respiratory infections. Therefore, option B is correct. Option A is incorrect because it states that adenoviral infections are restricted to the upper respiratory tract, which is not true. Option C is incorrect because there is no circumstance where adenoviral infections are solely limited to the upper respiratory tract. Option D is also incorrect as the correct answer is B.
Which are the most suitable materials for isolation of polio viruses
- A. feces, duodenal and bile content
- B. blood, sputum and urine
- C. only feces
- D. feces, nasopharyngeal swabs and cerebrospinal fluid
Correct Answer: D
Rationale: The correct answer is D because polio viruses are primarily found in the gastrointestinal tract and respiratory secretions. Feces, nasopharyngeal swabs, and cerebrospinal fluid are the most suitable materials for isolating polio viruses due to their presence in these body fluids. Feces contain the virus shed from the intestines, nasopharyngeal swabs collect respiratory secretions where the virus may be present, and cerebrospinal fluid is important for detecting the virus in cases of neurological complications. Choices A and B include irrelevant body fluids that are not typically associated with polio virus transmission. Option C is too limited as the virus can also be present in respiratory secretions and cerebrospinal fluid, not just feces.
A wound infection culture revealed Gram-positive cocci in clusters. The bacteria were catalase-positive and coagulase-negative. What is the most likely causative agent?
- A. Staphylococcus epidermidis
- B. Staphylococcus aureus
- C. Streptococcus pyogenes
- D. Enterococcus faecalis
Correct Answer: A
Rationale: The most likely causative agent in this case is Staphylococcus epidermidis. This conclusion can be drawn based on the characteristics provided: Gram-positive cocci in clusters, catalase-positive, and coagulase-negative. Staphylococcus epidermidis fits all these criteria.
Explanation of other choices:
- Staphylococcus aureus: Typically coagulase-positive, so it does not match the characteristics given.
- Streptococcus pyogenes: Gram-positive cocci in chains, not clusters. Also, it is catalase-negative.
- Enterococcus faecalis: Gram-positive cocci in pairs or chains, not clusters. Additionally, it is catalase-negative.
Therefore, Staphylococcus epidermidis is the most likely causative agent based on the provided characteristics.
For serological diagnostics of the whooping cough it was made large-scale reaction with parapertussis and pertussis diagnosticums. At the bottom of the test-tubes with diagnosticum of Bordetella parapertussis grain-like sediment formed. What antibodies have this reaction revealed?
- A. Bacteriolysins
- B. Precipitins
- C. Antitoxins
- D. Opsonins
Correct Answer: B
Rationale: Rationale:
1. The grain-like sediment indicates a precipitation reaction.
2. Precipitins are antibodies that cause precipitation reactions.
3. In serological diagnostics, precipitation reactions are used to detect specific antibodies.
4. Therefore, the reaction revealed in this scenario is due to the presence of precipitins.
Summary:
A: Bacteriolysins - These antibodies cause bacterial lysis, not precipitation.
C: Antitoxins - These antibodies neutralize toxins, not involved in precipitation reactions.
D: Opsonins - These antibodies enhance phagocytosis, not related to precipitation reactions.
A 35-year-old patient with a severe respiratory infection had sputum that showed Gram-negative, comma-shaped bacteria. What is the likely causative agent?
- A. Vibrio cholerae
- B. Shigella dysenteriae
- C. Campylobacter jejuni
- D. Helicobacter pylori
Correct Answer: C
Rationale: The correct answer is C: Campylobacter jejuni. This bacterium is Gram-negative and comma-shaped, commonly causing respiratory infections. Vibrio cholerae (A) causes cholera, not respiratory infections. Shigella dysenteriae (B) causes dysentery, not respiratory infections. Helicobacter pylori (D) is associated with gastric ulcers, not respiratory infections. Therefore, Campylobacter jejuni is the most likely causative agent based on the given information.