Nokea
Which of the following bacteria is known for producing a toxin that causes botulism?
- A. Clostridium botulinum
- B. Clostridium tetani
- C. Staphylococcus aureus
- D. Neisseria gonorrhoeae
Correct Answer: A
Rationale: The correct answer is A: Clostridium botulinum. This bacterium is known for producing botulinum toxin, which causes botulism. It is an anaerobic, spore-forming bacterium commonly found in soil. Clostridium tetani causes tetanus, not botulism. Staphylococcus aureus can cause food poisoning but not botulism. Neisseria gonorrhoeae is responsible for gonorrhea, not botulism. Therefore, A is the correct answer due to the specific association of Clostridium botulinum with botulism toxin production.
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A journalist's body temperature has sharply increased in the morning three weeks after his mission in India, it was accompanied with shivering and bad headache. A few hours later the temperature decreased. The attacks began to repeat in a day. He was diagnosed with tropical malaria. What stage of development of Plasmodium is infective for anopheles-female?
- A. Gametocytes
- B. B.Shizontes
- C. C.Merozoites
- D. E.Sporozoites
Correct Answer: D
Rationale: The correct answer is D: Sporozoites. Sporozoites are the infective stage of Plasmodium for the female Anopheles mosquito. Here's the rationale: After being transmitted to a human host through a mosquito bite, the sporozoites travel to the liver where they mature and reproduce asexually as merozoites (not the infective stage for mosquitoes). The merozoites then infect red blood cells, leading to symptoms like fever, headache, and shivering. During the blood stage, some merozoites develop into male and female gametocytes, which are not infective to mosquitoes. When a mosquito bites an infected person, it ingests gametocytes, which then develop into male and female gametes and fuse to form ookinetes. Ookinetes develop into oocysts in the mosquito's gut, releasing sporozoites that migrate to the salivary glands, ready to infect a new human host when the mosquito bites
Which of the following diseases is considered to fall in the group II category?
- A. Anthrax
- B. Lyme disease
- C. Mumps
- D. Smallpox
Correct Answer: C
Rationale: The correct answer is C: Mumps. Group II diseases are vaccine-preventable diseases that are communicable and can cause outbreaks. Mumps fits this criteria as it is preventable through vaccination, easily transmitted through respiratory droplets, and can lead to outbreaks in communities. Anthrax (A) is a zoonotic disease, Lyme disease (B) is transmitted by ticks, and Smallpox (D) has been eradicated.
A patient with a productive cough and fever had a sputum smear revealing Gram-positive cocci in clusters. What is the most likely causative agent?
- A. Staphylococcus aureus
- B. Streptococcus pneumoniae
- C. Neisseria meningitidis
- D. Klebsiella pneumoniae
Correct Answer: A
Rationale: The correct answer is A: Staphylococcus aureus. Staphylococcus aureus is a Gram-positive cocci bacterium that forms clusters and commonly causes pneumonia with a productive cough and fever. It is frequently found in sputum smears in such cases. Streptococcus pneumoniae (B) is another common cause of pneumonia but typically appears in pairs or chains, not clusters. Neisseria meningitidis (C) is a Gram-negative diplococcus that causes meningitis, not pneumonia. Klebsiella pneumoniae (D) is a Gram-negative bacterium that can cause pneumonia but appears as Gram-negative rods, not Gram-positive cocci in clusters.
A patient was taken to a hospital with acute food poisoning caused by homemade canned mushrooms. The product analysis revealed some microorganisms that develop only in the absence of oxygen. What microorganisms caused the poisoning?
- A. Obligate anaerobes
- B. Facultative anaerobes
- C. Microaerophiles
- D. Obligate aerobes
Correct Answer: A
Rationale: The correct answer is A: Obligate anaerobes. These microorganisms thrive in the absence of oxygen, as seen in the canned mushrooms where oxygen is limited. They produce toxins causing food poisoning. Facultative anaerobes (B) can survive with or without oxygen. Microaerophiles (C) require low levels of oxygen. Obligate aerobes (D) need oxygen to survive and would not be responsible for the poisoning in this case.
The bacterium Yersinia pestis is responsible for causing what disease?
- A. Tonsillitis
- B. Leprosy
- C. Plague
- D. Rat fever
Correct Answer: C
Rationale: The correct answer is C: Plague. Yersinia pestis is the bacterium responsible for causing the bubonic, septicemic, and pneumonic plague. The bacterium is transmitted to humans through infected flea bites or handling infected animals. Tonsillitis (A) is commonly caused by streptococcal bacteria, leprosy (B) is caused by Mycobacterium leprae, and rat fever (D) is another term for leptospirosis, caused by Leptospira bacteria.