Which bacteria are most commonly associated with food poisoning?
- A. Clostridium botulinum
- B. Salmonella enterica
- C. Escherichia coli
- D. All of the above
Correct Answer: D
Rationale: The correct answer is D: All of the above. Clostridium botulinum, Salmonella enterica, and Escherichia coli are all common bacteria associated with food poisoning. Clostridium botulinum produces a potent neurotoxin causing botulism. Salmonella enterica causes salmonellosis, a common foodborne illness. Escherichia coli can produce toxins leading to food poisoning. Therefore, since all three bacteria are known to cause food poisoning, the correct answer is D. Choices A, B, and C are incorrect because each of these bacteria individually is commonly associated with food poisoning, not just one of them.
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Which of the following pathogens can cause meningitis?
- A. Staph. aureus
- B. Strep. pyogenes
- C. Strep. pneumoniae
- D. None of the above
Correct Answer: C
Rationale: Rationale for choice C (Strep. pneumoniae):
1. Strep. pneumoniae is a common cause of bacterial meningitis.
2. It is a leading pathogen responsible for meningitis in adults and children.
3. It can invade the bloodstream and reach the meninges, causing inflammation.
4. Treatment guidelines often include antibiotics effective against Strep. pneumoniae.
Summary of why other choices are incorrect:
A. Staph. aureus is not a common cause of meningitis.
B. Strep. pyogenes typically causes streptococcal infections but not meningitis.
D. "None of the above" is incorrect as Strep. pneumoniae can cause meningitis.
The catarrhal stage of the whooping cough is characterized by:
- A. Decrease in paroxysms of coughing
- B. Subsequent respiratory infection for many months after the onset of pertussis
- C. Uncontrollable coughing followed by a high pitched 'whoop' sound
- D. Mild respiratory symptoms (mild coughing, sneezing or a runny nose)
Correct Answer: D
Rationale: The correct answer is D because the catarrhal stage of whooping cough is characterized by mild respiratory symptoms such as mild coughing, sneezing, or a runny nose. During this stage, the cough may start to worsen but is not yet severe.
A: Incorrect - Decrease in paroxysms of coughing is not seen in the catarrhal stage; it occurs later in the paroxysmal stage.
B: Incorrect - Subsequent respiratory infection for many months after the onset of pertussis is not a characteristic of the catarrhal stage.
C: Incorrect - Uncontrollable coughing followed by a high pitched 'whoop' sound is typical of the paroxysmal stage, not the catarrhal stage.
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 contain the highest concentration of the virus, while nasopharyngeal swabs and cerebrospinal fluid can also contain the virus. Blood, sputum, and urine do not typically contain high levels of polio virus. Choice A is incorrect as bile content is not a common site for polio virus isolation. Choice C is incorrect because only testing feces may not provide a comprehensive picture of the infection.
The so-called “red tide†is generally caused by which of the following organisms?
- A. Lichens
- B. Bacteria
- C. Pfiesteria
- D. Dinoflagellates
Correct Answer: D
Rationale: The correct answer is D: Dinoflagellates. Red tides are caused by the rapid growth of certain species of dinoflagellates, which are single-celled algae. These algae produce toxins that can harm marine life and humans. Lichens (A) are not associated with red tides. While some bacteria (B) can contribute to harmful algal blooms, they are not the primary cause of red tides. Pfiesteria (C) is a type of harmful algal species, but it is not the main organism responsible for red tides. Therefore, the correct answer is dinoflagellates (D) due to their ability to cause red tides through toxin production.
Which bacteria are known for causing food poisoning due to their production of enterotoxins?
- A. Clostridium botulinum
- B. Salmonella enterica
- C. Staphylococcus aureus
- D. All of the above
Correct Answer: D
Rationale: The correct answer is D, "All of the above." Clostridium botulinum produces botulinum toxin causing botulism. Salmonella enterica can produce enterotoxins causing food poisoning. Staphylococcus aureus also produces enterotoxins leading to food poisoning. Therefore, all three options can cause food poisoning due to their production of enterotoxins.