What drug should be administered for individual prevention of malaria?

Correct Answer: A

Rationale: The correct answer is A: Chingamin. Chingamin is a type of antimalarial drug that is commonly used for individual prevention of malaria. It works by targeting the malaria parasite in the body, preventing its growth and spread. Rifampicin (B), Ampicillin (C), and Gentamicin (D) are not effective for preventing malaria as they are antibiotics that target bacterial infections, not parasitic infections like malaria. Therefore, Chingamin is the most appropriate choice for individual prevention of malaria due to its specific antimalarial properties.

Correct Answer: C

Rationale: The correct answer is C because Koch's postulate states that a microorganism must be isolated in pure culture, grown in a laboratory setting, and then inoculated into animals to reproduce the same disease seen in the original host. This step demonstrates a direct cause-and-effect relationship between the isolated microorganism and the disease. Choice A is incorrect because not all cases of a disease may have the same microorganism present. Choice B is incorrect as isolating the microorganism alone does not prove its pathogenicity. Choice D is incorrect as it does not address the need for experimental reproduction of the disease in a new host.

Correct Answer: A

Rationale: The correct answer is A: Cell wall. In the Gram staining method, the primary differentiation of bacteria is based on the composition of their cell walls. Gram-positive bacteria have a thick layer of peptidoglycan in their cell walls, which retains the crystal violet dye and appears purple under the microscope. On the other hand, Gram-negative bacteria have a thinner layer of peptidoglycan and an outer membrane, which allows the crystal violet dye to be washed out during the decolorization step and take up the counterstain safranin, appearing pink. The different responses to stains are primarily due to the structural differences in the cell walls of these two types of bacteria. Summary: - Choice A: Cell wall is correct because it determines the differential staining in Gram staining. - Choice B: Cytoplasm is incorrect as it does not directly influence the staining properties of bacteria. - Choice C: Cytoplasmic membrane is incorrect as it is not the main structural

Correct Answer: B

Rationale: The correct answer is B because a supercapsid is a lipoprotein membrane that encloses the nucleocapsid, providing protection to the genetic material inside. This structure is distinct from the capsid which is the protein coat surrounding the nucleic acid. Choice A is incorrect as there is no shell located between the capsid and supercapsid. Choice C is incorrect as it describes the nucleocapsid itself, not the supercapsid. Choice D is incorrect as a protein envelope around the nucleic acid does not specifically refer to a supercapsid.

Correct Answer: A

Rationale: Step 1: Vibrio cholerae is a bacterium known to cause cholera, a foodborne illness transmitted through contaminated water. Step 2: Cholera outbreaks are often linked to unsanitary water sources, making Vibrio cholerae the correct choice. Step 3: Clostridium difficile causes gastrointestinal infections, not typically associated with contaminated water. Step 4: Mycobacterium tuberculosis causes tuberculosis, a respiratory disease, not related to foodborne illnesses. Step 5: Neisseria gonorrhoeae is a sexually transmitted bacterium, not linked to foodborne illnesses from contaminated water.

Correct Answer: C

Rationale: The correct answer is C: Pili. Pili are bacterial structures involved in conjugation, which is the process of transferring genetic material between bacterial cells. Pili facilitate the physical contact between donor and recipient cells, allowing for the transfer of plasmids or other genetic material. Capsules (choice A) are involved in protection and adherence, not conjugation. Flagella (choice B) are responsible for bacterial motility. Fimbriae (choice D) are also involved in adherence but not in conjugation. Therefore, the correct answer is C as pili specifically play a crucial role in the process of conjugation.

Correct Answer: D

Rationale: The correct answer is D: Neuraminidase inhibitors. Neuraminidase is an enzyme crucial for the release of new viral particles from infected cells during influenza infection. By inhibiting neuraminidase, the spread of the virus is limited. Protease inhibitors (choice A) are used to treat HIV, not influenza. Beta-lactamase inhibitors (choice B) are used in combination with beta-lactam antibiotics to increase their effectiveness against bacteria, not viruses. Reverse transcriptase inhibitors (choice C) are used to treat HIV by blocking the enzyme responsible for replicating the virus's genetic material, but they are not effective against influenza.

Correct Answer: A

Rationale: The correct answer is A: Pseudomonas aeruginosa. Pseudomonas aeruginosa is a gram-negative bacilli that produce pyocyanin, a blue-green pigment. The presence of greenish fluorescent colonies of gram-negative nonsporeforming bacilli that release blue-green pigment matches the characteristics of Pseudomonas aeruginosa. Now, let's analyze the other choices: B: Enterobacteriaceae - While some Enterobacteriaceae can be gram-negative bacilli, they do not typically produce pyocyanin or exhibit the specific characteristics described in the question. C: Staphylococcus aureus - Staphylococcus aureus is a gram-positive cocci, not a gram-negative bacilli. It does not match the given description. D: Staphylococcus epidermidis - Staphylococcus epidermidis is also a gram-positive cocci, not a gram-negative bacilli. It does

Correct Answer: A

Rationale: The correct answer is A: Escherichia coli. E. coli is the most common bacteria responsible for causing urinary tract infections due to its ability to adhere to the urinary tract lining and multiply rapidly. It is a normal inhabitant of the gut and can enter the urinary tract through improper hygiene practices. Salmonella enterica and Neisseria gonorrhoeae are typically associated with other infections like food poisoning and gonorrhea, respectively. Mycobacterium tuberculosis causes tuberculosis, not urinary tract infections. Thus, based on its prevalence and pathogenicity in the urinary tract, E. coli is the correct choice.