The patient 25 y.o. was admitted on the 1st day of the disease with complaints of double vision in the eyes, heavy breathing. The day before the patient ate homemade mushrooms. On objective examination: paleness, widened pupils, disorder of swallowing, bradycardia, constipation are marked. What is the diagnosis?

Correct Answer: A

Rationale: The correct answer is A: Botulism. Botulism is a rare but serious illness caused by a toxin produced by the bacterium Clostridium botulinum. In this case, the patient's symptoms align with botulism due to the ingestion of homemade mushrooms. The symptoms of double vision, heavy breathing, paleness, widened pupils, swallowing difficulties, bradycardia, and constipation are all classic signs of botulism poisoning. The toxin affects the nervous system and can lead to paralysis. The other choices (B: Yersiniosis, C: Leptospirosis, D: Salmonellosis) do not match the patient's symptoms and history of consuming mushrooms, making them incorrect.

Correct Answer: A

Rationale: The correct answer is A: Spores. The Ozheshko method is used to stain spores, which are resistant structures produced by certain bacterial species. By studying the smear of streptobacillus preparation under oil immersion, one can observe the presence of spores as distinct, oval bodies within the bacteria. Spores are important for bacterial survival in harsh conditions. Summary: B: Capsules are not typically stained using the Ozheshko method. Capsules are usually visualized using negative staining techniques. C: Flagella are not stained by the Ozheshko method. Flagella are visualized using special staining techniques like the flagella stain. D: Inclusions are not specifically stained by the Ozheshko method. Inclusions are often observed using techniques that highlight cellular structures or components.

Correct Answer: C

Rationale: The primary target of beta-lactam antibiotics is cell wall synthesis. These antibiotics inhibit enzymes called penicillin-binding proteins, which are essential for building the bacterial cell wall. By disrupting cell wall synthesis, beta-lactam antibiotics weaken the cell wall, leading to bacterial cell lysis and death. Protein synthesis (Choice A), DNA replication (Choice B), and folic acid synthesis (Choice D) are not directly targeted by beta-lactam antibiotics, making them incorrect choices.

Correct Answer: C

Rationale: The correct answer is C because Marburg virus and Ebola virus belong to the Filoviridae family. These viruses are characterized by their filamentous shape and are known to cause severe hemorrhagic fever in humans. Both viruses have caused outbreaks with high mortality rates. Choice A (Lassa virus and lymphocytic choriomeningitis viruses) are not part of the Filoviridae family. They belong to the Arenaviridae family, which also includes viruses that cause hemorrhagic fevers. Choice B (Chikungunya virus and Sindbis virus) are arboviruses belonging to the Togaviridae family, which are not related to the Filoviridae family. Choice D (Crimean-Congo virus and Hantaan virus) are part of the Nairoviridae and Hantaviridae families, respectively, and not the Filoviridae family.

Correct Answer: A

Rationale: The correct answer is A: Anatoxin. An anatoxin is a preparation that contains inactivated toxins produced by the anthrax-causing bacteria. By administering anatoxin, the population can develop immunity against the toxin without being exposed to the live bacteria. This specific prophylaxis approach helps prevent the development of anthrax infection by targeting the toxin itself. Summary: - Choice B (Inactivated vaccine) is incorrect because an inactivated vaccine typically contains killed or inactivated whole bacteria, not just the toxins. - Choice C (Chemical vaccine) is incorrect as there is no such thing as a chemical vaccine; vaccines are biological preparations. - Choice D (Genetically engineered vaccine) is incorrect because while vaccines can be genetically engineered, the specific term "genetically engineered vaccine" does not accurately describe the prophylaxis used against anthrax in this scenario.

Correct Answer: B

Rationale: The correct answer is B: Gram-negative bacteria. Gram-negative bacteria have an outer membrane containing lipopolysaccharides (LPS). In the Gram staining technique, these bacteria appear pink/red due to the thin peptidoglycan layer, which allows the crystal violet stain to be washed out, revealing the safranin counterstain. Gram-positive bacteria (choice A) have a thick peptidoglycan layer but lack an outer membrane with LPS. Choice C is incorrect since only Gram-negative bacteria possess LPS in their outer membrane. Choice D is incorrect as all bacteria can be classified as either Gram-positive or Gram-negative based on their cell wall structure.

Correct Answer: B

Rationale: The correct answer is B: presence of metachromatic granules. This is because Corynebacterium diphtheriae is known for containing metachromatic granules, which are characteristic of this species. These granules can be observed under a microscope and aid in the identification of the bacteria. Explanation of other choices: A: formation of spores - Corynebacterium diphtheriae does not form spores. Spore formation is more commonly seen in bacteria such as Bacillus and Clostridium species. C: production of coagulase - Coagulase production is a characteristic of Staphylococcus aureus, not Corynebacterium diphtheriae. D: beta-hemolysis on blood agar - Corynebacterium diphtheriae does not exhibit beta-hemolysis on blood agar. This type of hemolysis is more typical of Streptococcus pyogenes.

Correct Answer: A

Rationale: Exotoxins are proteins produced inside the microbe cell and then released outside the cell to exert their toxic effects on neighboring cells or tissues. This is why choice A is correct. Choices B and C are incorrect because exotoxins are not meant to act within the same cell they are produced in. Choice D is incorrect because exotoxins are usually released without causing cell lysis; they are secreted by the microbe actively rather than being leaked out due to cell damage.

Correct Answer: B

Rationale: Step-by-step rationale: 1. Marburg virus is named after the German city Marburg where it was first identified in 1967. 2. Chikungunya virus is named after a village in Tanzania. 3. Measles virus got its name from the Middle English word "maselen" meaning "many little spots". 4. Epstein-Barr virus is named after Michael Epstein and Yvonne Barr, who discovered it. Summary: B is correct as it is directly named after the city of its discovery. A, C, and D are incorrect as they are named after other locations, characteristics, or discoverers.