Most reliable test for detection of acute hepatitis A infection is

Correct Answer: B

Rationale: The correct answer is B: ELISA test for IgM anti-HAV in serum and HAV-Ag in stools. This test is the most reliable for detecting acute hepatitis A infection because IgM antibodies are produced early in the infection, indicating an active infection. Detection of HAV antigen in stools also confirms active viral shedding. A: Western blot assay for IgG anti-HAV in serum is not the most reliable for acute infection detection as IgG antibodies are produced later in the infection and indicate past exposure or immunity. C: ELISA test for IgG anti-HAV in serum is not the most reliable for acute infection detection as IgG antibodies are produced later in the infection and indicate past exposure or immunity. D: None of the above is incorrect as option B is the most appropriate choice for detecting acute hepatitis A infection.

Correct Answer: D

Rationale: The correct answer is D: Positive strand RNA viruses. These viruses have RNA genomes that can be directly translated by host ribosomes without the need for transcription. In contrast, single-strand DNA and double-strand DNA viruses require transcription to generate mRNA for translation. Choice A is incorrect as there is a correct answer. Choice B and C are incorrect because both single-strand DNA and double-strand DNA viruses require transcription for mRNA synthesis.

Correct Answer: A

Rationale: The correct answer is A: CMV (Cytomegalovirus). CMV is the most common congenital infection worldwide due to its high prevalence and ability to be transmitted from mother to fetus during pregnancy. It can lead to serious complications such as hearing loss, developmental delays, and vision problems in newborns. Listeria monocytogenes (B) is a foodborne pathogen, not typically associated with congenital infections. Rubella Virus (C) can cause congenital rubella syndrome but is less common globally compared to CMV. Syphilis (D) can also be transmitted from mother to fetus, but its prevalence and impact on congenital infections are lower compared to CMV.

Correct Answer: C

Rationale: The correct answer is C: To determine the antibiotic susceptibility of microorganisms. PCR is not suitable for determining antibiotic susceptibility as it is a technique used to amplify DNA/RNA, not to test for antibiotic resistance. To prove latent infection (A), PCR can be used to detect low levels of pathogens. For rapid diagnosis of infectious diseases (B), PCR is commonly used due to its sensitivity and specificity. To demonstrate DNA and RNA molecules (D), PCR is ideal as it can amplify and detect specific sequences. Therefore, choice C is incorrect as PCR is not designed for determining antibiotic susceptibility.

Correct Answer: C

Rationale: Rationale: Choice C is correct because Staphylococcus epidermidis, Escherichia coli, and Enterococcus spp. are common causative agents of nosocomial infections due to their presence on the skin, in the gut, and in healthcare settings. S. aureus and L. monocytogenes (Choice A) are also important pathogens but are less common in nosocomial infections. Enterobacteriaceae (Choice B) are a large family of bacteria that can cause infections but are not as commonly associated with nosocomial infections compared to the organisms in Choice C. The correct answer (Choice C) encompasses pathogens commonly found in healthcare settings, making it the most suitable option.