Patients after splenectomy are of high risk of infections caused by:

Correct Answer: D

Rationale: Rationale: After a splenectomy, patients are at high risk of infections caused by encapsulated bacteria such as Streptococcus pneumoniae, Listeria monocytogenes, and Salmonella. The spleen plays a crucial role in the immune response against encapsulated bacteria, and its absence increases susceptibility to these specific pathogens. Therefore, all choices are correct as patients are at risk of infections from all three types of bacteria mentioned.

Correct Answer: C

Rationale: Correct Answer: C: Halophiles Rationale: 1. Halophiles are bacteria adapted to high salt environments. 2. They have specific mechanisms to tolerate high salt concentrations. 3. Acidophiles thrive in acidic conditions. 4. Thermophiles prefer high temperature environments. 5. Mesophiles grow best at moderate temperatures.

Correct Answer: A

Rationale: The correct answer is A because Gram-negative bacteria have a unique cell envelope structure consisting of a cytoplasmic membrane, a peptidoglycan layer, and an outer membrane. The cytoplasmic membrane is the innermost layer that separates the cytoplasm from the external environment. The peptidoglycan layer provides structural support to the cell. The outer membrane acts as an additional protective barrier and contains lipopolysaccharides. Choice B is incorrect because Gram-negative bacteria have an outer membrane in addition to the cytoplasmic membrane and peptidoglycan layer. Choice C is incorrect because Gram-negative bacteria have more than just a peptidoglycan layer in their cell envelope. Choice D is incorrect as the cell envelope of Gram-negative bacteria does have specific components.

Correct Answer: A

Rationale: The correct answer is A: Mycolic acid in the cell wall. Mycolic acid is a unique component of the cell wall of Mycobacterium species, including the causative agent of tuberculosis. The Ziehl-Neelsen method uses acid-fast staining, where mycolic acid confers resistance to decolorization by acid-alcohol, causing the bacteria to retain the red stain. Choices B, C, and D are incorrect as capsules, flagella, and peptidoglycan layers do not directly contribute to acid-fast staining characteristic of Mycobacterium species.

Correct Answer: A

Rationale: Rationale: 1. Iodine solution contains iodine, a halogen with antiseptic properties. 2. Iodine is effective against fungi, making it suitable for treating dermatomycosis. 3. Iodine solution is commonly used in dermatology for its fungicidal properties. 4. Formalin, methylene blue, and brilliant green do not contain halogens or have fungicidal properties. Summary: - Formalin is a disinfectant, not an antiseptic for dermatomycosis. - Methylene blue is an antifungal dye, not used as an antiseptic. - Brilliant green is an antiseptic, but does not contain halogens or have fungicidal properties.

Correct Answer: A

Rationale: The most likely diagnosis is A: Pneumonic plague. The patient's symptoms align with the presentation of pneumonic plague, caused by the bacterium Yersinia pestis. Symptoms include high fever, severe headache, dyspnea, cough with bloody sputum, and cyanosis. The characteristic bubonic plague lymphadenopathy may be absent in the pneumonic form. The patient's recent travel history to India also raises suspicion, as plague is endemic in some regions. The other choices can be ruled out based on the patient's symptoms and presentation. Miliary tuberculosis typically presents with diffuse miliary nodules on imaging. Influenza typically presents with more generalized symptoms and does not usually cause rusty sputum. Ornithosis is caused by Chlamydophila psittaci and usually presents with pneumonia-like symptoms after exposure to infected birds.

Correct Answer: A

Rationale: The correct answer is A: Robert Hooke. Hooke published Micrographia in 1665, showcasing detailed illustrations of insects, sponges, and plant cells under the microscope. Hooke's work was groundbreaking in advancing the field of microscopy. Van Leeuwenhoek is known for discovering microorganisms but did not publish Micrographia. Janssen and Needham were not associated with Micrographia. Therefore, A is the correct answer.

Correct Answer: D

Rationale: The correct answer is D because all of the mentioned bacteria (Escherichia coli, Salmonella enterica, and Pseudomonas aeruginosa) are gram-negative bacteria that produce endotoxins in their cell walls. Endotoxins are released when the bacteria are destroyed, leading to the activation of the immune system and potentially causing septic shock. Escherichia coli and Salmonella enterica are common causes of gastrointestinal infections, while Pseudomonas aeruginosa is known for causing infections in immunocompromised individuals. Therefore, all three bacteria can produce endotoxins that contribute to septic shock. Choices A, B, and C are incorrect because each of these bacteria individually can produce endotoxins that lead to septic shock.

Correct Answer: A

Rationale: The most likely diagnosis is Epidemic typhus (Choice A) based on the symptoms described. The presence of roseolous-petechial rash, high fever (41oC), hyperemia of face, reddening of scleras, tremor of the tongue, tachycardia, and splenomegaly are classic signs of epidemic typhus. The rash typically appears around the 5th day of the disease. Summary: - B: Measles typically presents with a maculopapular rash starting on the face and spreading downward. It doesn't usually present with tremor of the tongue or splenomegaly. - C: Alcohol delirium is characterized by confusion, disorientation, and hallucinations due to alcohol consumption. It doesn't match the symptoms described. - D: Leptospirosis presents with fever, muscle pain, and conjunctival suffusion. It doesn't typically present with the specific rash and trem