Nokea
Which of the following stains is generally used for the diagnosis of tuberculosis?
- A. Acid-fast stain
- B. Gram stain
- C. Negative stain
- D. Simple stain
Correct Answer: A
Rationale: The correct answer is A: Acid-fast stain. This stain is used for diagnosing tuberculosis due to the unique cell wall composition of Mycobacterium tuberculosis, which resists decolorization by acid-alcohol. This allows the bacteria to retain the primary stain (carbol fuchsin) and appear red under a microscope. Gram stain (B) is not suitable for Mycobacterium tuberculosis as it is gram-positive but does not retain the crystal violet-iodine complex. Negative stain (C) is not used for bacterial identification. Simple stain (D) does not differentiate acid-fast bacteria like Mycobacterium tuberculosis.
You may also like to solve these questions
A mercury-containing compound used as a preservative in vaccines is:
- A. analgesic
- B. EDTA
- C. codeine
- D. thimerosal
Correct Answer: D
Rationale: The correct answer is D: thimerosal. Thimerosal is a mercury-containing compound used as a preservative in vaccines. It helps prevent contamination and growth of bacteria and fungi in multi-dose vials. Choice A, analgesic, refers to pain relievers, not preservatives. Choice B, EDTA, is a chelating agent used to bind metal ions and is not a preservative. Choice C, codeine, is an opioid pain medication and not a preservative used in vaccines. Thimerosal is the correct answer as it specifically fits the description of a mercury-containing compound used in vaccines.
Which one belongs to genus Orthopoxvirus?
- A. Vaccinia virus
- B. Smallpox virus
- C. Cowpox virus
- D. All of these
Correct Answer: D
Rationale: The correct answer is D because all three viruses, Vaccinia virus, Smallpox virus, and Cowpox virus, belong to the genus Orthopoxvirus. They share similar characteristics and genetic makeup. Vaccinia virus is used as a vaccine against smallpox, Smallpox virus causes smallpox disease, and Cowpox virus can infect both animals and humans. Choice A, B, and C are incorrect because each of these viruses is a member of the Orthopoxvirus genus.
Which bacteria is a common cause of bacterial meningitis?
- A. Neisseria meningitidis
- B. Streptococcus pneumoniae
- C. Haemophilus influenzae
- D. All of the above
Correct Answer: D
Rationale: The correct answer is D: All of the above. Neisseria meningitidis, Streptococcus pneumoniae, and Haemophilus influenzae are all common causes of bacterial meningitis. Neisseria meningitidis is often associated with outbreaks in community settings. Streptococcus pneumoniae is a leading cause of bacterial meningitis in adults. Haemophilus influenzae used to be a common cause in children before the introduction of the Hib vaccine. Therefore, since all three bacteria are known to cause bacterial meningitis, the correct answer is D. Choices A, B, and C are incorrect because each bacteria individually can cause bacterial meningitis, making "All of the above" the correct comprehensive answer.
The lipophilization is:
- A. Dehydration of the cell under deep vacuum in frozen state (-20.-30 degrees)
- B. Hydration of frozen cells
- C. Enrichment of the cells with proteins under deep vacuum
- D. Removing the protein content of the cell under deep vacuum
Correct Answer: A
Rationale: The correct answer is A because lipophilization is the process of removing water from cells under deep vacuum in a frozen state. Dehydration of the cell at a low temperature helps to preserve the cellular structure and components. Choice B is incorrect as hydration does the opposite of what lipophilization aims to achieve. Choice C is incorrect as lipophilization does not involve enriching cells with proteins. Choice D is incorrect as lipophilization does not involve removing protein content from cells.
Which one of the following microbiological diagnostic methods is the most suitable for detection of genitourinary chlamydiosis
- A. cultural diagnostic
- B. ELISA
- C. CFT
- D. PCR
Correct Answer: D
Rationale: The correct answer is D: PCR. PCR (Polymerase Chain Reaction) is the most suitable method for detecting genitourinary chlamydiosis due to its high sensitivity and specificity in detecting the genetic material of Chlamydia trachomatis. PCR can detect even low levels of the pathogen, providing accurate results.
A: Cultural diagnostic is not as sensitive as PCR and may take longer to produce results.
B: ELISA detects antibodies, which may not be present in early stages of infection, leading to false-negative results.
C: CFT (Complement Fixation Test) is an older method with lower sensitivity compared to PCR for detecting chlamydiosis.