In which of the following GIT infections, the pathogenesis consists mainly of invasion and intraepithelial multiplication without generalization of infectious process:

Correct Answer: C

Rationale: Rationale: 1. Shigella invades and multiplies within the intestinal epithelial cells, causing inflammation and tissue damage locally. 2. It does not spread systemically, unlike Yersinia enterocolitica and Listeria monocytogenes. 3. Shigella's pathogenesis is focused on invasion and multiplication at the site of infection, leading to symptoms of dysentery. 4. Yersinia enterocolitica and Listeria monocytogenes can disseminate beyond the gastrointestinal tract, causing systemic infections. Summary: - A (Yersinia enterocolitica) and B (Listeria monocytogenes) are incorrect as they can generalize the infectious process. - C (Shigella) is correct as it mainly involves invasion and intraepithelial multiplication without spreading systemically.

Correct Answer: B

Rationale: The correct answer is B: Aminoglycosides. Aminoglycosides are antibiotics that act by binding to the 30S ribosomal subunit, disrupting protein synthesis in bacteria. This interaction affects the ribosomes directly, leading to inhibition of bacterial protein production. Penicillins (A) work by inhibiting cell wall synthesis, Sulfonamides (C) target folic acid synthesis, and Quinolones (D) inhibit DNA gyrase. These mechanisms do not directly affect the ribosomes, making them incorrect choices in this context.

Correct Answer: B

Rationale: The correct answer is B: Typhoid fever, Brucellosis. Both Typhoid fever and Brucellosis are bacterial infections that can lead to bacteremia, the presence of bacteria in the bloodstream. In Typhoid fever, the causative agent Salmonella typhi can enter the bloodstream, causing bacteremia. Similarly, Brucellosis, caused by Brucella species, can also result in bacteremia. Choice A is incorrect because bacteremia is not typically observed in Diphtheria. Choice C, Cholera, is caused by a toxin-producing bacterium and does not usually lead to bacteremia. Choice D, Dysentery, is a condition characterized by bloody diarrhea and is primarily caused by parasites or bacteria that typically do not lead to bacteremia.

Correct Answer: A

Rationale: The correct answer is A: Francisella tularensis. This bacterium is classified as a class A bioterrorism agent due to its high virulence and potential for mass casualties. It can cause tularemia, a severe and potentially fatal disease. The other choices, Hepatitis B, E. coli, and Bacillus subtilis, are not considered class A bioterrorism agents. Hepatitis B is a virus causing liver inflammation, E. coli is a common bacterium found in the gut, and Bacillus subtilis is a beneficial bacterium used in various industries. Therefore, Francisella tularensis is the correct choice based on its high pathogenicity and bioterrorism potential.

Correct Answer: C

Rationale: The correct answer is C: Measles serological test. This is because the clinical presentation of high fever, maculopapular rash, and Filatov-Koplik's spots on the buccal mucosa are classic symptoms of measles. The presence of Filatov-Koplik's spots is highly specific for measles. Performing a measles serological test will help confirm the diagnosis by detecting measles-specific antibodies in the blood. Incorrect choices: A: Mumps serological test - Mumps typically presents with parotitis (swelling of the parotid glands) and not with Filatov-Koplik's spots. B: Enteroviruses serological test - Enteroviruses do not typically cause Filatov-Koplik's spots or the classic triad of symptoms seen in measles. D: Influenza virus serological test - Influenza virus does not cause Filatov-Koplik's spots and the characteristic rash seen