Nokea
Which of the following bacteria produces an endotoxin responsible for septic shock?
- A. Staphylococcus aureus
- B. Escherichia coli
- C. Neisseria meningitidis
- D. All of the above
Correct Answer: D
Rationale: The correct answer is D, "All of the above." Staphylococcus aureus, Escherichia coli, and Neisseria meningitidis all produce endotoxins that can lead to septic shock. Endotoxins are part of the outer membrane of Gram-negative bacteria, such as E. coli and N. meningitidis, which can trigger a severe immune response leading to septic shock. S. aureus, a Gram-positive bacterium, produces toxins that can also contribute to septic shock. Therefore, all of these bacteria can produce endotoxins responsible for septic shock. Choices A, B, and C are incorrect because they only identify individual bacteria that produce endotoxins, whereas the correct answer encompasses all bacteria listed.
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After 4 months of treatment for tuberculosis the patient began complaining of toes and fingers numbness, sensation of creeps. He was diagnosed with polyneuritis. What antituberculous drug might have caused these complications?
- A. Isoniazid
- B. Rifampicin
- C. Ciprofloxacin
- D. Sodium salt of benzylpenicillin
Correct Answer: A
Rationale: The correct answer is A: Isoniazid. Isoniazid is known to cause peripheral neuropathy as a side effect, especially with prolonged use. It can lead to symptoms such as numbness, tingling, and weakness in the toes and fingers due to its neurotoxic effects. Rifampicin (B) is less likely to cause neuropathy. Ciprofloxacin (C) is not typically associated with neuropathy. Sodium salt of benzylpenicillin (D) is an antibiotic but is not known to cause polyneuritis.
Which bacteria is commonly associated with foodborne illnesses?
- A. Streptococcus pneumoniae
- B. Campylobacter jejuni
- C. Mycobacterium tuberculosis
- D. Haemophilus influenzae
Correct Answer: B
Rationale: The correct answer is B: Campylobacter jejuni. This bacteria is commonly associated with foodborne illnesses due to its presence in undercooked poultry and unpasteurized milk. Campylobacteriosis is a leading cause of bacterial gastroenteritis. Streptococcus pneumoniae (A) causes pneumonia, not foodborne illnesses. Mycobacterium tuberculosis (C) causes tuberculosis, not foodborne illnesses. Haemophilus influenzae (D) can cause respiratory infections but is not commonly associated with foodborne illnesses.
For family Rhabdoviridae is true that:
- A. They are enveloped viruses
- B. They cause plague
- C. They have spherical shape
- D. They infect only humans
Correct Answer: A
Rationale: The correct answer is A: They are enveloped viruses. Rhabdoviridae family consists of enveloped viruses, which means they have a lipid envelope surrounding their protein coat. This envelope helps the virus in infecting host cells and evading the immune system. The other choices are incorrect because B: They cause plague is not true as Rhabdoviridae family typically causes diseases like rabies in mammals. C: They have spherical shape is incorrect as rhabdoviruses have a bullet-shaped structure. D: They infect only humans is also incorrect as Rhabdoviridae viruses can infect a wide range of hosts beyond just humans.
Which of the following bacteria is associated with stomach ulcers?
- A. Escherichia coli
- B. Helicobacter pylori
- C. Bacillus cereus
- D. Clostridium difficile
Correct Answer: B
Rationale: The correct answer is B: Helicobacter pylori. This bacterium is associated with stomach ulcers as it can survive in the acidic environment of the stomach and produce substances that weaken the stomach lining. Escherichia coli (A) is associated with foodborne illnesses, not ulcers. Bacillus cereus (C) causes food poisoning. Clostridium difficile (D) is associated with antibiotic-associated colitis, not ulcers. Therefore, Helicobacter pylori is the correct answer based on its specific association with stomach ulcers.
During sanitary and bacteriological testing of water with the membrane filter technique there were revealed two red colonies on a membrane filter (Endo agar) through which 500 ml of water was filtred. Calculate the coli index and coli titer of the analyzed water:
- A. 4 and 250
- B. 2 and 500
- C. 250 and 4
- D. 500 and 2
Correct Answer: C
Rationale: The correct answer is C (coli index of 250 and coli titer of 4). The coli index is calculated by multiplying the number of colonies by the reciprocal of the volume filtered, which gives 2 colonies x (1/0.5 L) = 4. The coli titer is obtained by dividing the volume filtered by the number of colonies, which gives 0.5 L / 2 colonies = 0.25 L or 250 ml. This indicates the concentration of coliform bacteria in the water sample.
Choice A (4 and 250) is incorrect because it has the correct coli index but the values are reversed for coli index and coli titer. Choice B (2 and 500) is incorrect as it provides the correct coli titer value but the values are reversed for coli index and coli titer. Choice D (500 and 2) is incorrect because it reverses the values for both coli index and coli titer.