Nokea
Bacteria capable of growing at low temperatures are called:
- A. mesophiles
- B. thermophiles
- C. psychrophiles
- D. halophiles
Correct Answer: C
Rationale: The correct answer is C: psychrophiles. Psychrophiles are bacteria that can grow at low temperatures, typically below 20°C. This is because they have adapted to survive and thrive in cold environments. Mesophiles (A) grow best at moderate temperatures, thermophiles (B) thrive in high temperatures, and halophiles (D) prefer high salt concentrations. Psychrophiles are specifically adapted to cold temperatures, making them the correct choice in this scenario.
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A patient with convulsive contractions of facial muscles was admitted to the infectious disease ward. From a scratch on his lower right extremity analysts isolated bacteria with terminal endospores that gave them drumstick appearance. What bacteria are compliant with given description?
- A. Clostridium tetani
- B. Clostridium botulinum
- C. Clostridium perfringens
- D. Bacillus anthracis
Correct Answer: A
Rationale: Step-by-step rationale for the correct answer (A - Clostridium tetani):
1. The patient has convulsive contractions of facial muscles, indicating tetanus.
2. Isolation of bacteria with terminal endospores that have a drumstick appearance is characteristic of Clostridium tetani.
3. Clostridium tetani produces tetanospasmin toxin causing muscle spasms.
4. Therefore, the correct answer is Clostridium tetani (A).
Summary of why other choices are incorrect:
B: Clostridium botulinum causes botulism, not tetanus.
C: Clostridium perfringens causes gas gangrene, not tetanus.
D: Bacillus anthracis causes anthrax, not tetanus.
A patient who suffered form syphilis took a course of antibiotic therapy and fully recovered. Some time later he was infected again with Treponema pallidum. What form of infection is it?
- A. Reinfection
- B. Recurrence
- C. Superinfection
- D. Secondary infection
Correct Answer: A
Rationale: The correct answer is A: Reinfection. This is because the patient fully recovered from the initial syphilis infection after antibiotic therapy, indicating the elimination of the pathogen. Subsequently getting infected again with Treponema pallidum suggests a new exposure to the same pathogen, resulting in a new infection. Recurrence (B) would imply the reactivation of the same infection, which is not the case here. Superinfection (C) refers to a new infection that occurs on top of an existing infection, which is not the scenario described. Secondary infection (D) typically refers to an infection that occurs after an initial infection weakens the immune system, which is not the case in this scenario.
How do people get infected with diphtheria
- A. by swimming in contaminated water
- B. by transmission
- C. by droplets and physical contact
- D. by contaminated food
Correct Answer: C
Rationale: The correct answer is C because diphtheria is primarily spread through respiratory droplets and physical contact with an infected person. The bacteria responsible for diphtheria is transmitted through coughing, sneezing, or sharing personal items. Swimming in contaminated water (A) does not spread diphtheria. Transmission (B) is a broad term and does not specifically address the mode of transmission for diphtheria. Contaminated food (D) is not a typical route of diphtheria transmission. Therefore, option C is the most accurate choice based on the known mode of transmission for diphtheria.
Which of the following bacteria is responsible for causing syphilis?
- A. Treponema pallidum
- B. Neisseria gonorrhoeae
- C. Chlamydia trachomatis
- D. Escherichia coli
Correct Answer: A
Rationale: Step 1: Treponema pallidum is a spirochete bacterium known to cause syphilis.
Step 2: It is sexually transmitted and can cause various stages of disease.
Step 3: Neisseria gonorrhoeae causes gonorrhea, not syphilis.
Step 4: Chlamydia trachomatis causes chlamydia, not syphilis.
Step 5: Escherichia coli is a common gut bacterium and not responsible for syphilis. Treponema pallidum is the correct answer as it is the specific bacterium known to cause syphilis.
Basing upon the data of laboratory assessment of sanitary state of soil in a certain territory, the soil was found to be low-contaminated according to the sanitary indicative value; contaminated according to the coli titer; low-contaminated according to the anaerobe titer (Cl. perfringens). This is indicative of:
- A. Fresh fecal contamination
- B. Old fecal contamination
- C. Insufficient intensity of soil humification
- D. Constant entry of organic protein contaminations
Correct Answer: A
Rationale: Step 1: The soil is low-contaminated according to the sanitary indicative value, which indicates that the contamination is recent.
Step 2: The soil is contaminated according to coli titer, suggesting the presence of coliform bacteria typically found in fresh fecal matter.
Step 3: The soil is low-contaminated according to the anaerobe titer (Cl. perfringens), which is an indicator of recent fecal contamination.
Step 4: Based on the above steps, the correct answer is A: Fresh fecal contamination, as the presence of coliform bacteria and recent anaerobe titer levels point to recent fecal contamination.
Summary:
B: Old fecal contamination - Incorrect because the indicators suggest recent contamination.
C: Insufficient intensity of soil humification - Incorrect as it is not related to the specific indicators mentioned in the question.
D: Constant entry of organic protein contaminations - Incorrect as the indicators point towards fecal contamination, not protein