Nokea
Which of the following bacteria can be transmitted via droplets in the air?
- A. Streptococcus pneumoniae
- B. Escherichia coli
- C. Clostridium botulinum
- D. Mycobacterium tuberculosis
Correct Answer: D
Rationale: The correct answer is D: Mycobacterium tuberculosis. This bacterium can be transmitted via droplets in the air through coughing or sneezing. It is spread through respiratory droplets containing the bacteria. Streptococcus pneumoniae (A) is transmitted through direct contact with respiratory secretions, not through droplets in the air. Escherichia coli (B) is commonly transmitted through contaminated food or water, not through the air. Clostridium botulinum (C) is typically transmitted through contaminated food, not via respiratory droplets. Therefore, the correct choice is D as it is the only bacterium listed that can be transmitted via droplets in the air.
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The optimal PH for most pathogenic bacteria and viruses is:
- A. 5.0-5.5
- B. 8.0-9.6
- C. 7.2-7.4
- D. 4.2-4.4
Correct Answer: C
Rationale: The correct answer is C (7.2-7.4) because most pathogenic bacteria and viruses thrive in a neutral pH environment close to 7.0. This pH range is optimal for their growth and survival. Choice A (5.0-5.5) is too acidic for most pathogens. Choice B (8.0-9.6) is too alkaline, which is not conducive for their survival. Choice D (4.2-4.4) is also too acidic and would likely inhibit the growth of pathogenic bacteria and viruses. Thus, a pH range of 7.2-7.4 provides the most suitable conditions for their proliferation.
Bacteria that have been identified as frequently responsible for nonsexually transmitted infections of the reproductive system include:
- A. Escherichia coli, Gardnerella vaginalis, and Staphylococcus aureus
- B. Streptococcus faecalis, Klebsiella oxytoca, and Serratia marcescens
- C. Clostridium tetani, Bacillus cereus, and Staphylococcus aureus
- D. Neisseria gonorrhoeae, Helicobacter pylori, and Pseudomonas aeruginosa
Correct Answer: A
Rationale: The correct answer is A (Escherichia coli, Gardnerella vaginalis, and Staphylococcus aureus) because they are known to commonly cause nonsexually transmitted infections of the reproductive system. Escherichia coli can cause urinary tract infections that can ascend to the reproductive system. Gardnerella vaginalis is associated with bacterial vaginosis, a common infection of the vagina. Staphylococcus aureus can cause infections in the reproductive system through various means.
Choices B, C, and D are incorrect:
B: Streptococcus faecalis, Klebsiella oxytoca, and Serratia marcescens are not commonly associated with reproductive system infections.
C: Clostridium tetani and Bacillus cereus are not typically involved in reproductive system infections.
D: Neisseria gonorrhoeae causes sexually transmitted infections, Helicobacter pylori causes gastrointestinal issues, and Pseudomonas aeruginosa is more
A child with fever and a sore throat had a Gram-stained smear revealing Gram-positive cocci in chains. The bacteria were beta-hemolytic. What is the likely causative agent?
- A. Streptococcus pyogenes
- B. Streptococcus pneumoniae
- C. Staphylococcus aureus
- D. Enterococcus faecalis
Correct Answer: A
Rationale: The correct answer is A: Streptococcus pyogenes. The presence of Gram-positive cocci in chains suggests a streptococcal infection. Beta-hemolysis indicates the production of a hemolysin that lyses red blood cells, a characteristic of Streptococcus pyogenes. This bacterium is known to cause strep throat and can present with fever and sore throat.
Summary:
- B: Streptococcus pneumoniae is a common cause of pneumonia but typically appears as lancet-shaped cocci, not in chains.
- C: Staphylococcus aureus is a gram-positive cocci in clusters, not chains, and is not typically beta-hemolytic.
- D: Enterococcus faecalis is a gram-positive cocci that are part of the normal gut flora and are not typically beta-hemolytic or found in chains.
A healthy man is in a region with high risk of catching malaria. What drug should be administered for individual chemoprophylaxis of malaria?
- A. Chingamin
- B. Sulfalen
- C. Tetracycline
- D. Metronidazole
Correct Answer: A
Rationale: The correct answer is A: Chingamin (also known as Chloroquine). Chingamin is the drug of choice for chemoprophylaxis of malaria in regions with high risk. It is effective against Plasmodium falciparum, the most common malaria parasite. Chingamin is well-tolerated, affordable, and has a long track record of use. Sulfalen (Choice B) is not commonly used for malaria prophylaxis. Tetracycline (Choice C) is not recommended for malaria prophylaxis due to poor efficacy and resistance development. Metronidazole (Choice D) is not effective against malaria parasites.
Granulomas containing lymphocytes and macrophages were detected during analysis of skin biopsy material. Among macrophages there are large cells with fat inclusions, which contain microorganisms in spheric packages (Virchow's cells). The following disease is based on the described type of hypersensitivity:
- A. Leprosy
- B. Syphilis
- C. Tuberculosis
- D. Rhinoscleroma
Correct Answer: C
Rationale: The correct answer is C: Tuberculosis. Granulomas with lymphocytes and macrophages containing Virchow's cells (large cells with fat inclusions containing microorganisms) are classic findings in tuberculosis. Leprosy (A) typically presents with granulomas but with different histopathological features. Syphilis (B) does not usually form granulomas in the skin. Rhinoscleroma (D) is a chronic bacterial infection characterized by nodular lesions but does not typically involve Virchow's cells as seen in tuberculosis.