During the staining of sputum smear of a patient with suspected croupous pneumonia the following reactives and stainers were used: gentian violet solution, Lugol's solution, 960 spiritus and water fuchsin. What method of staining is used in this case?

Correct Answer: A

Rationale: The correct answer is A: Leffler's method. In this staining method, gentian violet solution is used as the primary stain, followed by Lugol's solution as a mordant, 960 spiritus as a decolorizer, and water fuchsin as a counterstain. Gentian violet stains the organisms purple, Lugol's solution helps in fixing the dye, 960 spiritus decolorizes non-specifically, and water fuchsin acts as a counterstain to help visualize the bacteria. Leffler's method is specifically used for staining sputum smears in suspected cases of croupous pneumonia. Summary: B: Gram's staining uses crystal violet, iodine, alcohol, and safranin. It is mainly used for distinguishing between Gram-positive and Gram-negative bacteria. C: Ziehl-Neelsen's staining is used for acid-fast bacteria like Mycobacterium tuberculosis using carbol fuchsin and acid-alcohol

Correct Answer: A

Rationale: The correct choice is A: Binding to IgE fixed to mast cells. The Besredka desensitization method involves injecting small, gradually increasing doses of the allergen to induce tolerance and prevent anaphylactic shock. This process works by binding the allergen to IgE antibodies fixed to mast cells, which prevents the release of histamine and other inflammatory mediators that trigger allergic reactions. This desensitization process helps the immune system become less reactive to the allergen over time. Incorrect choices: B: Inhibited synthesis of mast cells mediators - This choice does not reflect the mechanism of the Besredka desensitization method, which involves binding to IgE on mast cells. C: Stimulation of the immunological antigen tolerance - While this may sound plausible, the Besredka method specifically targets the IgE-mast cell interaction. D: Stimulation of antigen-specific IgG synthesis - While IgG antibodies may play a role in desensitization, the

Correct Answer: B

Rationale: The correct answer is B because anaerobic bacteria can grow in environments without oxygen. Anaerobic bacteria do not require oxygen for their metabolism and energy production. They can thrive in oxygen-deprived conditions by using alternative electron acceptors. Choice A is incorrect because anaerobic bacteria do not require oxygen to survive. Choice C is incorrect because anaerobic bacteria typically cannot survive in the presence of high concentrations of oxygen. Choice D is incorrect because anaerobic bacteria do not perform photosynthesis.

Correct Answer: B

Rationale: The correct answer is B: acidic pH. The reproductive tract's acidic pH serves as a defense mechanism by creating an environment hostile to many pathogens, preventing microbial infection. The acidic pH helps to inhibit the growth and survival of harmful microorganisms. A: Alkaline pH would actually be more favorable for microbial growth as most pathogens thrive in neutral to alkaline pH environments. C: High sugar concentration can actually promote microbial growth as many pathogens feed on sugars. D: High body temperature may help in some cases, but it is not as effective as an acidic pH in preventing microbial infection in the reproductive tract.

Correct Answer: D

Rationale: The correct answer is D: Tuberculosis. Tuberculosis is considered a reemerging disease due to the increase in drug-resistant strains, high global prevalence, and challenges in diagnosis and treatment. This is supported by global health organizations' reports on the resurgence of TB cases. A: AIDS is not considered a reemerging disease as there has been significant progress in HIV prevention and treatment. B: Ebola outbreaks are sporadic and localized, not considered reemerging on a global scale. C: West Nile virus outbreaks occur periodically, but it is not considered a reemerging disease compared to TB.

Correct Answer: B

Rationale: Step-by-step rationale: 1. Sodium is the major cation in the intracellular fluid. 2. It plays a crucial role in maintaining cell volume and transmitting nerve impulses. 3. Potassium is the major cation in the extracellular fluid, not intracellular. 4. Bicarbonate and sulfate are anions and not major cations in intracellular fluid. Summary: Choice B (sodium) is correct as it is the major cation in intracellular fluid, essential for various cellular functions. Choices A, C, and D are incorrect as potassium is extracellular, while bicarbonate and sulfate are anions and not predominant cations in intracellular fluid.

Correct Answer: B

Rationale: The correct answer is B: genotype. The genotype refers to the actual genetic makeup of an organism, including all the genes and alleles present in its DNA. This determines the traits and characteristics of an organism. Phenotype (A) is the observable physical or biochemical characteristics of an organism. Conjugation (C) is a process in bacteria involving the transfer of genetic material. Construct (D) is not a term related to genetics. Therefore, the correct choice is B as it specifically refers to the genetic composition of an organism.

Correct Answer: B

Rationale: The correct answer is B: Motility. The bacterial flagellum is a whip-like appendage that helps bacteria move by rotating like a propeller. This motility allows bacteria to navigate their environment, find nutrients, and avoid harmful conditions. Choices A, C, and D are incorrect because the bacterial flagellum is not involved in protein synthesis, DNA replication, or spore formation. Protein synthesis occurs in ribosomes, DNA replication takes place in the nucleus or nucleoid, and spore formation is a specialized process involving the production of spores for survival in harsh conditions.

Correct Answer: A

Rationale: The correct answer is A: Isoniazid. Isoniazid is a first-line drug for treating active pulmonary tuberculosis due to its high efficacy and low toxicity. It works by inhibiting the synthesis of mycolic acids in the bacterial cell wall. Sulfalen, Cyclocerine, and Ethionamide are not first-line drugs for tuberculosis. Sulfalen is used for urinary tract infections, Cyclocerine for drug-resistant tuberculosis, and Ethionamide as a second-line drug for multidrug-resistant tuberculosis. Therefore, Isoniazid is the most appropriate initial choice for treating active focal pulmonary tuberculosis.