How is detected viral multiplication in cell culture

Correct Answer: D

Rationale: The correct answer is D (A and B both). In viral multiplication, the presence of a specific cytopathic effect (CPE) in cell culture indicates viral replication. This is detected visually through changes in cell morphology. Additionally, immunofluorescence detection methods can be used to detect viral antigens within infected cells, confirming viral multiplication. Options C is incorrect as viral colonies are not typically used to detect viral multiplication in cell culture. Option B alone is not sufficient as it only focuses on immunofluorescence detection, while option A alone may not always be specific. Therefore, the combination of A and B provides a more comprehensive and accurate detection method for viral multiplication in cell culture.

Correct Answer: B

Rationale: Rationale: 1. Streptococcus pyogenes is the causative agent of strep throat. 2. If untreated, strep throat can lead to rheumatic fever. 3. Rheumatic fever is an autoimmune complication of streptococcal infections. 4. E. coli, S. epidermidis, and S. aureus are not typically associated with rheumatic fever.

Correct Answer: A

Rationale: The correct answer is A: Clostridium botulinum. This bacterium produces the neurotoxin responsible for botulism. Clostridium perfringens is associated with gas gangrene, not botulism. Streptococcus pneumoniae causes pneumonia, and Neisseria gonorrhoeae causes gonorrhea, not botulism. Therefore, A is the correct choice.

Correct Answer: B

Rationale: The correct answer is B: microvilli. Pili are hair-like structures found on the surface of some bacteria, while microvilli are microscopic cellular projections that increase surface area for absorption in cells like intestinal cells. Pili are involved in bacterial adhesion, while microvilli are important for nutrient absorption. Therefore, the correct answer is B. Incorrect choices: A: Fimbriae are short, thin appendages found on the surface of some bacteria, mainly used for adhesion. C: Cilia are hair-like structures found on the surface of some eukaryotic cells, often involved in movement or sensory functions. D: Flagella are long, whip-like appendages used for bacterial motility.

Correct Answer: B

Rationale: The correct answer is B because filoviruses, such as Ebola virus, require investigation in specifically equipped laboratories with high biological protection due to their high pathogenicity and risk of transmission. This is essential for ensuring the safety of researchers and preventing outbreaks. A: This is incorrect as filoviruses are not the most common cause of gastroenteritis; they primarily cause severe hemorrhagic fevers. C: Filoviruses are not widespread; they are typically confined to specific regions during outbreaks. D: Mass immunization is not used for filoviruses as there is no established vaccine for general prophylaxis.

Correct Answer: C

Rationale: Correct Answer: C: dermatophytes Rationale: 1. Dermatophytes are fungi that specifically infect the skin, hair, and nails. 2. They are the most common fungi causing such infections in humans. 3. Plasmodium and sporozoites are parasites causing malaria, not skin diseases. 4. Nematodes are a type of roundworm and do not typically cause skin, hair, or nail infections. In summary, dermatophytes are the correct answer because they are specialized fungi that commonly cause skin, hair, and nail diseases, distinguishing them from the other choices.

Correct Answer: D

Rationale: Step 1: Mantoux test measures cell-mediated immunity response to tuberculosis. Step 2: A negative result means no significant immune response to TB antigens. Step 3: Option A is incorrect, as it refers to antitoxic immunity, not cell immunity. Step 4: Option B is incorrect, as it mentions antibodies, not cell-mediated immunity. Step 5: Option C is incorrect, as it states absence of antibodies, not cell immunity. Step 6: Option D is correct as it directly correlates with the purpose of Mantoux test.

Correct Answer: A

Rationale: Step-by-step rationale: 1. Blue-green pigment + fruity odor are characteristic of Pseudomonas aeruginosa. 2. P. aeruginosa is a Gram-negative bacterium commonly associated with wound infections. 3. P. aeruginosa is known for its ability to produce pyocyanin (blue-green pigment) and a sweet, fruity odor. 4. Other choices like E. coli, K. pneumoniae, and P. mirabilis do not typically produce blue-green pigment or fruity odor. 5. Therefore, based on the characteristics observed, the likely causative agent is Pseudomonas aeruginosa. Summary of other choices: - Escherichia coli: Does not produce blue-green pigment or fruity odor. - Klebsiella pneumoniae: Does not typically produce blue-green pigment or fruity odor. - Proteus mirabilis: Does not produce blue-green pigment or fruity odor.

Correct Answer: C

Rationale: Rationale: 1. Psychrophilic: Grow best in cold temperatures 2. Mesophilic: Grow best in moderate temperatures 3. Thermophilic: Grow best in high temperatures - Choice A is incorrect as "thermophobic" is not a recognized term. - Choice B is incorrect as "psychophobic" is not a recognized term. - Choice D is incorrect as "mesophobic" is not a recognized term.