Which of the following viruses can cause hemorrhagic cystitis?

Correct Answer: A

Rationale: The correct answer is A: BK virus. BK virus is a common cause of hemorrhagic cystitis, especially in immunocompromised individuals. It infects the urinary tract, leading to inflammation and bleeding in the bladder. Enteroviruses, Flaviviruses, and Coronaviruses do not typically cause hemorrhagic cystitis. Enteroviruses usually cause respiratory and gastrointestinal infections, Flaviviruses are commonly associated with diseases like dengue fever and Zika virus, and Coronaviruses are known for causing respiratory illnesses such as COVID-19. Hence, the correct answer is A as it is the only virus among the options known to cause hemorrhagic cystitis.

Correct Answer: B

Rationale: The correct answer is B: to sequester iron from the environment. Siderophores are molecules produced by bacteria to chelate and acquire iron, an essential nutrient for their growth and survival. By sequestering iron, bacteria can compete with host cells and other microbes for this vital resource. This enhances their ability to thrive and establish infections. Choices A, C, and D are incorrect because siderophores do not directly enhance antibiotic resistance, form capsules, or perform oxidative phosphorylation. These functions are unrelated to the primary role of siderophores in iron acquisition.

Correct Answer: C

Rationale: The correct answer is C: acetyl-CoA. Acetyl-CoA is the compound that combines with oxaloacetic acid at the beginning of the Krebs cycle to form citric acid. This step is essential for the cycle to proceed, making acetyl-CoA the correct choice. A: Citric acid is formed after acetyl-CoA combines with oxaloacetic acid, so it is a product of the reaction, not the compound that enters the cycle. B: Pyruvic acid is converted to acetyl-CoA in a separate process before entering the Krebs cycle. D: Phosphoglyceraldehyde is not involved in the Krebs cycle; it is a compound in glycolysis.

Correct Answer: B

Rationale: The correct answer is B: Tuberculosis. The case describes a man with a perforation in the hard palate and features of caseous necrosis with granulation tissue, endovasculitis, and a cellular infiltration mainly of lymphocytes, epithelioid cells, and plasma cells. These findings are classic for tuberculosis infection, commonly seen in extrapulmonary sites like the oral cavity. Syphilis (choice A) typically presents with a painless ulcer and different histopathological features. Leprosy (choice C) presents with granulomas containing foamy macrophages. Scleroma (choice D) is caused by Klebsiella rhinoscleromatis and presents with chronic granulomatous inflammation.

Correct Answer: A

Rationale: The correct answer is A: Blue pus bacillus. Pseudomonas genus includes bacteria that commonly cause diseases in plants. Blue pus bacillus is a common name for Pseudomonas aeruginosa, a well-known bacterium that causes diseases in medicinal plants. Explanation: 1. Blue pus bacillus (Pseudomonas aeruginosa) is a member of the Pseudomonas genus known for causing diseases in plants. 2. Colon bacillus (Escherichia coli) belongs to the Enterobacteriaceae family, not the Pseudomonas genus. 3. Proteus is a genus of the Enterobacteriaceae family, not Pseudomonas. 4. Mycoplasma is a genus of bacteria that lack a cell wall and are not related to the Pseudomonas genus. In summary, the correct answer is A because it is a member of the Pseudomonas genus known for causing diseases in medicinal plants, while

Correct Answer: A

Rationale: The correct answer is A: viruses. Viruses are always in a parasitic form of interaction with the individual because they cannot survive or reproduce outside of a host cell. They rely on host cells to replicate and cause harm. Non-pathogenic bacteria (choice B) do not always cause harm and can coexist with the individual. Facultative pathogenic bacteria (choice C) can switch between being beneficial and harmful. Therefore, the correct answer is A as viruses always rely on a host for survival and reproduction.

Correct Answer: B

Rationale: The correct answer is B: Mycobacterium tuberculosis. This bacterium is responsible for causing tuberculosis. Mycobacterium tuberculosis specifically targets the lungs, leading to respiratory symptoms and can spread to other parts of the body. Streptococcus pneumoniae (A) is known for causing pneumonia, Neisseria meningitidis (C) causes meningitis, and Clostridium botulinum (D) causes botulism, not tuberculosis. Mycobacterium tuberculosis is the only bacterium among the choices that is associated with tuberculosis.

Correct Answer: C

Rationale: The correct answer is C because disinfectants are non-selective and can harm a wide range of microbial cells. Disinfectants work by disrupting cell membranes, proteins, and nucleic acids, affecting both harmful and beneficial microorganisms. Choices A and B are incorrect because disinfectants are designed to be potent and non-selective. Choice D is incorrect because the effects of disinfectants are often permanent and irreversible on microbial cells.

Correct Answer: C

Rationale: The correct answer is C: Staphylococcus aureus. This bacterium is commonly associated with hospital-acquired infections due to its ability to cause a wide range of infections and its resistance to multiple antibiotics. Staphylococcus aureus can cause skin infections, pneumonia, bloodstream infections, and surgical site infections, making it a significant threat in healthcare settings. Escherichia coli (choice A) is more commonly associated with foodborne illnesses. Clostridium difficile (choice B) is known for causing antibiotic-associated diarrhea. Bacillus anthracis (choice D) is primarily associated with anthrax infections, which are not typically acquired in hospital settings.