Nokea
A patient with a sore throat and fever had a throat culture revealing Gram-positive cocci in pairs with a capsule. What is the most likely causative agent?
- A. Streptococcus pneumoniae
- B. Staphylococcus aureus
- C. Neisseria meningitidis
- D. Klebsiella pneumoniae
Correct Answer: A
Rationale: The correct answer is A: Streptococcus pneumoniae. This bacterium is a Gram-positive cocci that often appear in pairs and can have a capsule. It is a common cause of sore throat and fever, known as streptococcal pharyngitis. Staphylococcus aureus (B) is a Gram-positive cocci but does not typically form pairs. Neisseria meningitidis (C) is a Gram-negative diplococcus and is more associated with meningitis. Klebsiella pneumoniae (D) is a Gram-negative rod and not typically associated with sore throat and fever.
You may also like to solve these questions
Which of the following bacteria is responsible for causing the disease known as tuberculosis?
- A. Mycobacterium tuberculosis
- B. Neisseria meningitidis
- C. Salmonella enterica
- D. Streptococcus pneumoniae
Correct Answer: A
Rationale: The correct answer is A: Mycobacterium tuberculosis. This bacteria is responsible for causing tuberculosis because it is the specific pathogen known to infect the lungs and other parts of the body, leading to the disease. Mycobacterium tuberculosis has unique cell wall components that allow it to evade the immune system and survive in the host.
Neisseria meningitidis (B) causes meningitis, not tuberculosis. Salmonella enterica (C) causes food poisoning, not tuberculosis. Streptococcus pneumoniae (D) causes pneumonia, not tuberculosis. Therefore, the correct answer is A based on the specific characteristics and pathogenicity of Mycobacterium tuberculosis.
Which of the following media is the most selective for Vibrio cholerae?
- A. MacConkey's agar
- B. Chocolate agar
- C. SS agar
- D. TCBS
Correct Answer: D
Rationale: The correct answer is D: TCBS. Thiosulfate-citrate-bile salts-sucrose (TCBS) agar is the most selective for Vibrio cholerae due to its high salt content, bile salts, and sucrose. Vibrio cholerae can grow well in alkaline conditions, which are provided by TCBS agar. MacConkey's agar (A) is selective for gram-negative bacteria, but not specifically for Vibrio cholerae. Chocolate agar (B) is a non-selective medium suitable for fastidious organisms. SS agar (C) is selective for Salmonella and Shigella species, not Vibrio cholerae.
A smear of sputum from the patient with suspected lobar pneumonia was stained with the use of the following stains and reagents: solution of gentian violet, Lugol's solution, 96o alcohol, water-magenta. What staining method was applied in this case?
- A. Gram
- B. Ziehl-Nielsen
- C. Romanovsky
- D. Neisser
Correct Answer: A
Rationale: The correct answer is A: Gram staining method. This method involves staining with gentian violet, followed by Lugol's solution, 96% alcohol decolorization, and counterstaining with safranin or water-magenta. This staining sequence allows for the differentiation of bacteria based on their cell wall composition. In the case of lobar pneumonia, the causative agent is typically a bacterium with a cell wall that retains the crystal violet stain after decolorization with alcohol, indicating a Gram-positive bacterium.
Summary of Incorrect Choices:
B: Ziehl-Nielsen staining is used for acid-fast bacteria like Mycobacterium tuberculosis, not for lobar pneumonia.
C: Romanovsky staining is primarily used in the identification of blood cells and blood parasites, not for bacteria.
D: Neisser staining is not a commonly used staining method in microbiology for bacterial identification.
The cleanup of various industrial wastes by living organisms is referred to as __________.
- A. biomining
- B. biosynthesis
- C. bioremediation
- D. bioengineering
Correct Answer: C
Rationale: The correct answer is C: bioremediation. Bioremediation is the process of using living organisms to clean up environmental pollution, including industrial wastes. This method utilizes microorganisms, plants, or fungi to break down or neutralize pollutants. Biomining (A) is the process of extracting valuable metals from ores using biological organisms. Biosynthesis (B) refers to the production of complex molecules by living organisms. Bioengineering (D) involves the application of engineering principles to biological systems, not specifically related to cleaning up industrial wastes. Therefore, the most appropriate term for the cleanup of industrial wastes by living organisms is bioremediation.
A patient consulted a stomatologist about purulent inflammation of his gums. What drug will be the most effective if it is suspected that a causative agent is an anaerobe?
- A. Metronidazole
- B. Gentamicin C.Oxacillin D.Co-trimoxazole E.-
Correct Answer: A
Rationale: The correct answer is A: Metronidazole. Anaerobic bacteria are sensitive to metronidazole due to its mechanism of action targeting their DNA. Metronidazole is often the drug of choice for treating infections caused by anaerobic bacteria. Gentamicin, Oxacillin, and Co-trimoxazole are not effective against anaerobes. Gentamicin is an aminoglycoside mostly used for aerobic bacteria, Oxacillin is a beta-lactam antibiotic effective against gram-positive bacteria, and Co-trimoxazole is a combination of sulfamethoxazole and trimethoprim mainly used for urinary tract infections and some respiratory infections.