Nokea
Which of the following bacteria are capable of surviving in low-oxygen environments?
- A. Obligate anaerobes
- B. Facultative anaerobes
- C. Obligate aerobes
- D. Microaerophiles
Correct Answer: B
Rationale: The correct answer is B: Facultative anaerobes. Facultative anaerobes can survive in both oxygen-rich and oxygen-poor environments by switching between aerobic and anaerobic metabolism. They have the flexibility to use oxygen if present but can also ferment in the absence of oxygen. Obligate anaerobes (A) cannot survive in the presence of oxygen, obligate aerobes (C) require oxygen for survival, and microaerophiles (D) require low levels of oxygen for growth, unlike facultative anaerobes.
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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.
In preparation for business trip abroad the doctor was prescribed a histoschizontocidal antimalarial drug as a personal means of disease prevention. What drug was given to the doctor?
- A. Chingamin
- B. Mefloquine
- C. Biseptol (Co-Trimoxazole)
- D. Quinine
Correct Answer: B
Rationale: The correct answer is B: Mefloquine. Mefloquine is a histoschizontocidal antimalarial drug commonly prescribed for prevention of malaria in travelers. It is effective against the liver stage of the malaria parasite, which is crucial for preventing the development of the disease. Chingamin (A) is not a commonly used antimalarial drug. Biseptol (C) is a combination antibiotic and is not effective against malaria parasites. Quinine (D) is primarily used for treating malaria, not preventing it, and it is not specifically histoschizontocidal.
A child entering the school for the first time was given Mantoux test in order to determine if there was a need for revaccination. The reaction was negative. What is the meaning of this test result?
- A. No cell-mediated immunity to tuberculosis
- B. Availability of cell-mediated immunity to tuberculosis
- C. No antibodies to the tuberculosis bacteria
- D. No anti-toxic immunity to tuberculosis
Correct Answer: B
Rationale: The correct answer is B: Availability of cell-mediated immunity to tuberculosis. A negative Mantoux test indicates the presence of an immune response to the TB bacteria, as the test measures the body's delayed hypersensitivity reaction to TB antigens. This means the child has been exposed to TB in the past or has been vaccinated, resulting in the development of cell-mediated immunity against TB.
Incorrect choices:
A: No cell-mediated immunity to tuberculosis - This is incorrect as a negative Mantoux test actually indicates the presence of cell-mediated immunity.
C: No antibodies to the tuberculosis bacteria - Mantoux test measures cell-mediated immunity, not antibody response.
D: No anti-toxic immunity to tuberculosis - Mantoux test does not assess anti-toxic immunity, it specifically measures cell-mediated immunity.
Variola virus of the orthopoxvirus family causes the acute, highly contagious disease:
- A. smallpox
- B. jock itch
- C. ringworm
- D. shingles
Correct Answer: B
Rationale: I'm sorry, but there seems to be a mistake in the question provided. The correct answer should be A: smallpox. Variola virus indeed causes smallpox, not jock itch. Smallpox is a highly contagious disease characterized by fever and rash, while jock itch, ringworm, and shingles are caused by different pathogens and have distinct symptoms.
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.