Nokea
Legionella pneumophila is:
- A. Gram-negative coccus
- B. Gram-negative spiral bacterium
- C. Gram-negative coccobacillus
- D. Gram-positive coccobacillus
Correct Answer: C
Rationale: Legionella pneumophila is a Gram-negative coccobacillus. It is not a coccus (round shape), spiral bacterium, or Gram-positive coccobacillus. The correct answer is C because Legionella pneumophila has a characteristic coccobacillary shape and stains Gram-negative due to its cell wall composition. The other choices are incorrect because they do not accurately describe the morphology or staining characteristics of Legionella pneumophila.
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Transduction is:
- A. Transformation
- B. Transfer of genetic material between donor and recipient bacterial cells with the help of latent phage
- C. Transfer of large plasmids from a donor cell to a recipient cell
- D. None of the above
Correct Answer: B
Rationale: Transduction is the transfer of genetic material between bacterial cells with the help of a phage (virus). This process involves a phage infecting a bacterial cell, replicating inside it, and then transferring bacterial DNA along with phage DNA to another bacterial cell. This is different from transformation (choice A) which involves the uptake of naked DNA by a bacterial cell and plasmid transfer (choice C) which involves the transfer of small, circular DNA molecules. Therefore, the correct answer is B because it specifically describes the process of transduction in bacteria, while choices A and C describe different mechanisms of genetic transfer.
Which of the following sites of the human body does not have a normal flora?
- A. Intestine
- B. Skin
- C. Vagina
- D. Blood
Correct Answer: D
Rationale: The correct answer is D: Blood. Normal flora refers to the microorganisms that naturally inhabit specific areas of the body. Blood is considered a sterile environment in healthy individuals, meaning it does not harbor any microorganisms under normal circumstances. In contrast, the intestine, skin, and vagina all have normal flora as they provide suitable environments for various microbial species to thrive. The presence of normal flora in these sites helps maintain a balance and protect against pathogenic invaders. Blood, being a vital and sterile fluid, is not meant to have any resident microbial populations.
Infection caused by the genus Candida can be successfully treated with:
- A. Penicillins
- B. Cephalosporins of third generation
- C. Nystatin
- D. None of the above
Correct Answer: C
Rationale: Step-by-step rationale for why choice C (Nystatin) is the correct answer:
1. Nystatin is an antifungal medication specifically effective against Candida infections.
2. Candida is a type of fungus, not a bacteria targeted by penicillins (choice A) or cephalosporins (choice B).
3. Nystatin works by disrupting the fungal cell membrane, leading to its death.
4. Choice D (None of the above) is incorrect as Nystatin is a suitable treatment option for Candida infections.
Laboratory diagnosis of Rotavirus infection includes
- A. Egg inoculation
- B. Sensitive laboratory animals
- C. Ascoli test
- D. Cell cultures
Correct Answer: D
Rationale: The correct answer is D: Cell cultures. Rotavirus diagnosis involves detecting viral antigens in stool samples using cell cultures. Cell cultures allow for the replication of the virus, facilitating its identification. A: Egg inoculation and B: Sensitive laboratory animals are not commonly used for Rotavirus diagnosis due to ethical concerns and practical limitations. C: Ascoli test is used for detecting specific proteins in serum, not for Rotavirus detection in stool samples. In summary, cell cultures are the most appropriate method for laboratory diagnosis of Rotavirus infection due to their ability to support viral replication and antigen detection.
Which of the following characteristics of mumps infection is NOT true:
- A. Only the person can be infected
- B. Is a vaccine-preventable disease
- C. Is a highly contagious disease
- D. Transmission routes are via air droplets and direct contact
Correct Answer: A
Rationale: Step-by-step rationale:
1. Mumps is a contagious disease transmitted through air droplets and direct contact.
2. The correct answer is A because mumps can infect both humans and animals.
3. Choice B is incorrect as mumps is vaccine-preventable.
4. Choice C is correct as mumps is highly contagious.
5. Choice D is accurate as mumps is transmitted via air droplets and direct contact.
Summary:
The correct answer is A because mumps can infect both humans and animals, making it untrue that only humans can be infected. Choices B, C, and D are incorrect as mumps is vaccine-preventable, highly contagious, and transmitted through air droplets and direct contact.