Detection of galactomannan and free mannan is used for diagnosing:

Correct Answer: A

Rationale: The correct answer is A: Aspergillosis and candidiasis. Galactomannan is a polysaccharide found in Aspergillus cell walls and is detected in patients with invasive aspergillosis. Free mannan is a polysaccharide found in Candida cell walls and is detected in patients with candidiasis. Therefore, detection of galactomannan and free mannan is specific for diagnosing Aspergillosis and candidiasis. Choices B, C, and D are incorrect as HIV infection, syphilis, and leptospirosis do not involve the detection of galactomannan or free mannan for diagnosis.

Correct Answer: A

Rationale: The correct answer is A: Tetanus. Tetanus is caused by the bacterium Clostridium tetani, commonly found in soil, dust, and animal feces. The patient's history of a stab wound increases the risk of tetanus infection as the bacterium can enter the body through the wound. Tetanus infection can lead to symptoms such as lockjaw or trismus, which are characterized by muscle stiffness and difficulty opening the mouth. This is due to the neurotoxin produced by Clostridium tetani affecting the muscles. Summary of incorrect choices: B: Brucellosis is a bacterial infection transmitted from animals to humans through consumption of unpasteurized dairy products. It does not typically manifest with symptoms of lockjaw. C: Whooping cough (Pertussis) is a respiratory infection caused by Bordetella pertussis bacteria. It presents with severe coughing fits but does not cause lockjaw. D: Anaerobic wound infection

Correct Answer: A

Rationale: Rationale: Shigella dysenteriae produces Shiga toxin, which inhibits protein synthesis by inactivating the 60S ribosomal subunit. This disrupts the translation process, leading to cell death. Escherichia coli (choice B) does not produce a toxin that inhibits protein synthesis. Clostridium tetani (choice C) produces tetanospasmin, which affects the nervous system. Staphylococcus aureus (choice D) produces toxins that cause food poisoning but do not inhibit protein synthesis.

Correct Answer: B

Rationale: The correct answer is B: IgM. IgM is the first antibody synthesized by the infant soon after birth. It is produced by B cells in response to initial exposure to antigens. IgA is mainly found in mucosal areas, IgG is transferred from mother to fetus, and IgD functions in the early stages of B cell development. Therefore, IgM is the most suitable choice as the antibody synthesized by the infant soon after birth.

Correct Answer: A

Rationale: The correct answer is A: Mycobacterium tuberculosis. This bacterium is known for causing tuberculosis, as it specifically infects the lungs and can lead to serious respiratory issues. Mycobacterium leprae (Choice B) causes leprosy, not tuberculosis. Escherichia coli (Choice C) is a common bacteria found in the intestines and is not associated with tuberculosis. Streptococcus pneumoniae (Choice D) causes pneumonia, but not tuberculosis. Therefore, the correct choice is A because Mycobacterium tuberculosis is the specific bacterium responsible for causing tuberculosis.

Correct Answer: D

Rationale: Step 1: The symptoms of optic nerve neuritis, memory impairment, and cramps are indicative of ethambutol toxicity. Step 2: Ethambutol is known to cause optic nerve toxicity leading to neuritis, as well as CNS toxicity causing memory impairment. Step 3: Ethambutol can also lead to peripheral neuropathy manifesting as cramps. Step 4: Isoniazid is associated with peripheral neuropathy and hepatotoxicity but not with optic nerve neuritis or memory impairment. Step 5: PASA is not commonly used for tuberculosis treatment and does not cause the described symptoms. Step 6: Rifampicin is known for hepatotoxicity and flu-like symptoms, but not specifically for optic nerve neuritis, memory impairment, or cramps. Summary: Ethambutol is the correct answer due to its known side effects of optic nerve toxicity, CNS toxicity, and peripheral neuropathy, which align with the presented symptoms. Ison

Correct Answer: B

Rationale: The correct answer is B because Gram-negative bacteria have an outer membrane with lipopolysaccharides, which is a key characteristic used in Gram staining. This outer membrane is responsible for the pink/red color seen when stained with Gram stain. Choice A is incorrect because Gram-negative bacteria have a thin peptidoglycan layer. Choice C is incorrect because Gram-negative bacteria stain pink, not purple. Choice D is incorrect because all bacteria have a cell wall, but Gram-negative bacteria have a different structure compared to Gram-positive bacteria.

Correct Answer: D

Rationale: The correct answer is D: Trichomonas tenax. Trichomonas tenax is a flagellated protozoan that is commonly found in the oral cavity, specifically in dental plaque. The description provided in the question matches the characteristics of Trichomonas tenax, such as unicellular structure, distinct layers in the cytoplasm, wide pseudopodia, and barely visible core. Entamoeba gingivalis (choice A) and Entamoeba histolytica (choice B) are amoebas, not flagellated protozoa, and they do not exhibit the characteristics described in the question. Lamblia (choice C) is also an incorrect choice as it is a different type of protozoan that does not match the description provided.

Correct Answer: B

Rationale: Step-by-step rationale for why B (Gamma Interferon) is the correct answer: 1. Gamma Interferon is a type of immunomodulator that helps regulate the immune response. 2. It activates macrophages and enhances the immune system's ability to fight infections. 3. Rifampin is an antibiotic, not an immunomodulator. 4. Hexacima and Pentaxim are combination vaccines, not immunomodulators. In summary, Gamma Interferon is the correct answer as it directly influences the immune response, while the other choices are not immunomodulators.