A 30 year old patient consulted a doctor about having diarrhea and stomach aches for 5 days, temperature rise up to 37,50C with chills. The day before the patient was in a forest and drank some water from an open pond. He was diagnosed with amebic dysentery that was bacteriologically confirmed. Name the medication for treatment of this disease:

Correct Answer: A

Rationale: The correct answer is A: Metronidazole. Amebic dysentery is caused by the parasite Entamoeba histolytica, not a bacterium, hence antibiotics like Chloramphenicol or Phthalazole are ineffective. Metronidazole is the drug of choice for treating amebic dysentery due to its efficacy against anaerobic organisms like Entamoeba histolytica. Furasolidone is used for treating bacterial infections, not parasitic ones like amebiasis. The patient's symptoms of diarrhea, stomach aches, and a recent history of drinking water from a potentially contaminated source in the forest are indicative of a parasitic infection, supporting the choice of Metronidazole for treatment.

Correct Answer: D

Rationale: The correct answer is D: mixed infection. In a mixed infection, multiple infectious agents establish themselves at the same site, leading to a complex and diverse infection. This type of infection can involve different types of pathogens such as bacteria, viruses, fungi, and parasites. It can be challenging to diagnose and treat due to the presence of multiple pathogens. A: Chronic infection refers to an infection that persists over a long period but is typically caused by a single pathogen. B: Necrotizing infection is characterized by rapid tissue destruction but does not necessarily involve multiple infectious agents. C: Fatal infection does not specify the presence of multiple infectious agents, it simply implies that the infection leads to death. In summary, the correct answer, mixed infection, is the only choice that specifically describes the scenario of multiple infectious agents establishing themselves at the same site.

Correct Answer: A

Rationale: Rationale: 1. Endo agar inhibits the growth of Gram-positive bacteria. 2. Colorless colonies on Endo agar indicate lactose non-fermenting bacteria. 3. Shigella dysenteriae is a lactose non-fermenting, Gram-negative rod, causing dysentery. 4. Salmonella typhi, Escherichia coli, and Proteus vulgaris are lactose fermenters, so they would produce pink colonies on Endo agar. Therefore, the most likely causative agent is Shigella dysenteriae.

Correct Answer: D

Rationale: The correct answer is D: Yersinia enterocolitica. This bacterium can contaminate foods and grow at refrigerator temperatures due to its psychrotrophic nature. Yersinia enterocolitica is known to cause foodborne illnesses even when stored at cold temperatures. Shigella sonnei is a human pathogen transmitted through fecal-oral route, Campylobacter jejuni is typically found in poultry and causes food poisoning, and E. coli can cause foodborne illnesses but does not grow well at refrigerator temperatures.

Correct Answer: D

Rationale: The correct answer is D because it encompasses the true statements regarding the laboratory diagnosis of urinary tract infections. A: Bacteriuria of less than 10^5 can be significant in treated patients due to the development of antibiotic resistance. B: Staphylococcus aureus, Salmonella typhi, and Mycobacterium tuberculosis may be significant regardless of quantity due to their pathogenic nature. C: Leukocyturia indicates inflammation, and even a lower number of leukocytes can be clinically significant. Therefore, option D covers all these aspects making it the correct choice.

Correct Answer: B

Rationale: The correct answer is B: peak effect. When drug receptors are maximally activated, it means the drug has reached its highest effectiveness, resulting in the peak effect. This occurs when the drug concentration is at its highest level in the body, leading to the maximum response. Threshold level (A) refers to the minimum amount of drug needed to produce a response. Cessation effect (C) is when the drug's effect wears off. Latency time (D) is the time it takes for the drug to start producing an effect. So, the peak effect best describes the scenario where drug receptors are maximally activated.

Correct Answer: B

Rationale: The correct answer is B because peritrichous bacteria have flagella distributed all over their surface, allowing them to move in various directions. Choice A is incorrect because bacteria with a single flagellum at one pole are called monotrichous. Choice C is incorrect as bacteria with a single flagellum at each pole are known as amphitrichous. Choice D is incorrect because peritrichous bacteria have multiple flagella all over their surface, not limited to one or both poles.

Correct Answer: A

Rationale: The correct answer is A: BCG vaccine. Step 1: BCG vaccine is specifically designed to protect against tuberculosis, making it the appropriate choice for newborns. Step 2: STI vaccine is for sexually transmitted infections, not tuberculosis. Step 3: EV vaccine is not a recognized vaccine. Step 4: DPT vaccine protects against diphtheria, pertussis, and tetanus, not tuberculosis. In summary, BCG vaccine is the correct choice as it targets tuberculosis specifically, while the other options are designed for different purposes.

Correct Answer: D

Rationale: The correct answer is D: Granulomatosis. The appearance of a 10 mm papule 48 hours after the Mantoux test indicates a delayed-type hypersensitivity reaction, which is characteristic of granulomatosis. This type of reaction involves activation of macrophages and T cells, leading to the formation of granulomas. Granulomas are organized collections of immune cells that wall off the antigen, in this case, the tuberculin antigen. A, B, and C are incorrect: A: Cellular cytotoxicity involves the destruction of target cells by immune cells such as cytotoxic T cells or natural killer cells. This mechanism is not associated with the delayed-type hypersensitivity reaction seen in granulomatosis. B: Anaphylaxis is a rapid and severe allergic reaction involving IgE-mediated release of histamine and other inflammatory mediators. This is not the mechanism underlying the delayed-type hypersensitivity reaction in the Mantoux test. C: Antibody-dependent cytotoxic