Which of the following bacteria is known for producing a neurotoxin that causes botulism?
- A. Clostridium botulinum
- B. Clostridium perfringens
- C. Streptococcus pneumoniae
- D. Neisseria gonorrhoeae
Correct Answer: A
Rationale: The correct answer is A: Clostridium botulinum. This bacterium produces the neurotoxin responsible for botulism. Clostridium perfringens is associated with gas gangrene, not botulism. Streptococcus pneumoniae causes pneumonia, and Neisseria gonorrhoeae causes gonorrhea, not botulism. Therefore, A is the correct choice.
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Gram staining is used to differentiate bacteria based on:
- A. size and shape
- B. presence of flagella
- C. cell wall composition
- D. genetic material
Correct Answer: C
Rationale: The correct answer is C: cell wall composition. Gram staining differentiates bacteria based on the structure of their cell walls. It classifies bacteria into Gram-positive (thick peptidoglycan layer) and Gram-negative (thin peptidoglycan layer). This differentiation is crucial for identifying bacterial species and guiding treatment choices. Size and shape (choice A) are not specific to Gram staining. Presence of flagella (choice B) is related to bacterial motility, not Gram staining. Genetic material (choice D) is not directly assessed by Gram staining. Overall, the unique composition of the cell wall is the key factor in distinguishing bacteria through Gram staining.
Medical examination of the first-year pupils included Mantoux test. 15 pupils out of 35 had negative reaction. What actions should be taken against children with negative reaction?
- A. BCG vaccination
- B. Antitoxin vaccination
- C. Rabies vaccination
- D. Repeat Mantoux test
Correct Answer: A
Rationale: The correct answer is A: BCG vaccination. The Mantoux test is used to detect tuberculosis infection. A negative reaction means the child is not infected. BCG vaccination is recommended for individuals without prior TB infection to prevent severe forms of the disease. Antitoxin and rabies vaccinations are not related to TB and are not indicated in this scenario. Repeating the Mantoux test is unnecessary since a negative result indicates absence of TB infection.
Which of the following diseases is not caused by enteroviruses?
- A. Myocarditis
- B. Infectious mononucleosis
- C. Herpangina
- D. Boston Exanthema
Correct Answer: B
Rationale: Answer B, Infectious mononucleosis, is not caused by enteroviruses. Infectious mononucleosis is primarily caused by the Epstein-Barr virus, a member of the herpesvirus family, not by enteroviruses. Enteroviruses are known to cause diseases such as myocarditis, herpangina, and Boston exanthema. Therefore, B is the correct answer. Myocarditis, herpangina, and Boston exanthema can all be caused by enteroviruses, making choices A, C, and D incorrect, respectively.
Which of the following viruses has the name of the city where it was first discovered:
- A. Chikungunya virus
- B. Marburg virus
- C. Measles virus
- D. Epstein-Barr virus
Correct Answer: B
Rationale: Step-by-step rationale:
1. Marburg virus is named after the German city Marburg where it was first identified in 1967.
2. Chikungunya virus is named after a village in Tanzania.
3. Measles virus got its name from the Middle English word "maselen" meaning "many little spots".
4. Epstein-Barr virus is named after Michael Epstein and Yvonne Barr, who discovered it.
Summary:
B is correct as it is directly named after the city of its discovery. A, C, and D are incorrect as they are named after other locations, characteristics, or discoverers.
The patient has developed pain in the axillary area, rise of temperature developed 10 hours ago. On examination: shaky gait is marked, the tongue is coated by white coating. The pulse is frequent. The painful lymphatic nodules are determined in the axillary area. The skin is erythematous and glistering over the lymphatic nodules. What is the most probable diagnosis?
- A. Bubonic plague
- B. Acute purulent lymphadenitis
- C. Lymphogranulomatosis
- D. Tularemia
Correct Answer: D
Rationale: The most probable diagnosis is D: Tularemia. Tularemia is a bacterial infection caused by Francisella tularensis. The symptoms described align with tularemia, such as pain in axillary area, fever, shaky gait, coated tongue, frequent pulse, painful lymphatic nodules, and erythematous skin over nodules. The key features pointing towards tularemia are the presence of lymphadenitis in the axillary area and the erythematous, glistering skin over the nodules, which are characteristic of ulceroglandular tularemia. Bubonic plague (A) presents with painful, swollen lymph nodes called buboes but typically lacks the erythematous skin findings. Acute purulent lymphadenitis (B) usually presents with pus-filled lymph nodes but does not typically cause shaky gait or coated tongue. Lymphogranulomatosis (C) is a term for Hodgkin's lymphoma, which does not