Nokea
The most common causative agent of bacterial meningitis are:
- A. E. Coli K1, Streptococcus group B (S. agalactiae), Listeria monocytogenes
- B. Haemophilus influenzae, Streptococcus pneumoniae, Neisseria meningitidis
- C. Staphylococcus aureus, pseudomonas aeruginosa
- D. None of the above
Correct Answer: B
Rationale: The correct answer is B because Haemophilus influenzae, Streptococcus pneumoniae, and Neisseria meningitidis are the most common causative agents of bacterial meningitis. Haemophilus influenzae is often seen in children, Streptococcus pneumoniae is the most common in adults, and Neisseria meningitidis is common in adolescents and young adults.
Choice A is incorrect because although Streptococcus group B and Listeria monocytogenes can cause meningitis, E. Coli K1 is not a common causative agent. Choice C is incorrect because Staphylococcus aureus and Pseudomonas aeruginosa are not typically associated with bacterial meningitis. Choice D is incorrect as there are known causative agents for bacterial meningitis.
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A 45-year-old patient complains of body temperature rise up to 40oC, general weakness, headache, painfulness and spastic muscle contractions around the wound in the shin. He received this wound 5 days ago when working in his garden. He requested no medical care back then. What wound infection can be suspected?
- A. Tetanus
- B. Anthrax
- C. Erysipelas
- D. Gram-positive
Correct Answer: A
Rationale: The correct answer is A: Tetanus. The patient's symptoms of muscle contractions, fever, and wound history suggest tetanus, caused by Clostridium tetani bacteria commonly found in soil. The spastic muscle contractions around the wound are classic for tetanus due to the neurotoxin produced by the bacteria. General weakness and headache are also common symptoms.
B: Anthrax is unlikely as it presents with different symptoms such as skin lesions, respiratory symptoms, and gastrointestinal symptoms.
C: Erysipelas is characterized by red, swollen patches on the skin, not consistent with the symptoms described.
D: Gram-positive is not a specific diagnosis but a broad category of bacteria. Tetanus is caused by Clostridium tetani, which is a Gram-positive bacterium, but this choice does not provide a specific infection diagnosis.
A patient with pneumonia had sputum cultured on Endo agar, revealing red colonies. The bacteria were Gram-negative rods. What is the most likely causative agent?
- A. Escherichia coli
- B. Klebsiella pneumoniae
- C. Pseudomonas aeruginosa
- D. Proteus mirabilis
Correct Answer: A
Rationale: Rationale for correct answer (A: Escherichia coli):
1. Endo agar selects for Gram-negative bacteria.
2. Red colonies on Endo agar indicate lactose fermentation, characteristic of E. coli.
3. E. coli is a common cause of pneumonia, especially in immunocompromised patients.
Summary of why other choices are incorrect:
- B: Klebsiella pneumoniae: Typically forms mucoid colonies on agar.
- C: Pseudomonas aeruginosa: Produces characteristic greenish-blue colonies on agar.
- D: Proteus mirabilis: Does not typically ferment lactose, so would not produce red colonies on Endo agar.
Which of the following bacteria is most commonly associated with nosocomial infections?
- A. Corynebacterium diphtheriae
- B. Shigella sonnei
- C. Pseudomonas aeruginosa
- D. None of the above
Correct Answer: C
Rationale: Rationale:
1. Pseudomonas aeruginosa is commonly found in hospital environments.
2. It is an opportunistic pathogen causing various nosocomial infections.
3. Its ability to develop resistance to antibiotics makes it a significant threat.
4. Corynebacterium diphtheriae causes diphtheria, not common nosocomial infections.
5. Shigella sonnei causes foodborne illness, not typically nosocomial infections.
6. "None of the above" is incorrect as Pseudomonas is indeed commonly associated with nosocomial infections.
The toxic condition caused by the multiplication of bacteria in the blood is referred to as:
- A. bacteremia
- B. septicemia
- C. shock
- D. bloodborne infection
Correct Answer: B
Rationale: The correct answer is B: septicemia. Septicemia specifically refers to the presence of bacteria in the bloodstream, leading to a systemic inflammatory response. Bacteremia (choice A) is simply the presence of bacteria in the blood without the systemic inflammatory response. Shock (choice C) is a state of circulatory collapse, often seen in severe septicemia. Bloodborne infection (choice D) is a general term for infections transmitted through the blood but does not specifically refer to the condition of bacterial multiplication causing toxicity.
The most important virulence factor of Bordetella pertussis is:
- A. the flagellum
- B. pertussis toxin
- C. P fimbriae
- D. mannose-resistant adhesins
Correct Answer: B
Rationale: The correct answer is B: pertussis toxin. This toxin is the most important virulence factor of Bordetella pertussis because it plays a key role in causing the characteristic symptoms of whooping cough. Pertussis toxin interferes with the host's immune response, leading to inflammation and tissue damage in the respiratory tract. The other choices (A: the flagellum, C: P fimbriae, D: mannose-resistant adhesins) are important for bacterial attachment and colonization, but they do not directly contribute to the severity of the disease like pertussis toxin does.