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: A

Rationale: The correct answer is A: Yersinia pestis. Y. pestis causes bubonic plague, characterized by enlarged, painful lymph nodes called buboes. The Gram-negative rods with a safety pin appearance are seen on Gram stain of Y. pestis. The other choices are incorrect because Francisella tularensis causes tularemia, not lymphadenitis with safety pin appearance. Brucella abortus causes brucellosis, which typically does not present with lymphadenitis. Clostridium botulinum causes botulism, which is not associated with lymphadenitis or safety pin appearance.

Correct Answer: D

Rationale: The correct answer is D because virulent strains of Listeria monocytogenes exhibit multiple pathogenic factors. A: They do not have endotoxin-like substances, so this is incorrect. B: They are indeed facultative intracellular bacteria, aiding in their ability to survive and replicate inside host cells. C: They produce hemolysin, which helps them lyse red blood cells. Therefore, the correct answer is D, as all of the above statements are true for virulent strains of Listeria monocytogenes.

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

Correct Answer: A

Rationale: The correct answer is A: Escherichia coli. On Endo agar, lactose-fermenting bacteria produce red colonies due to acid production. Escherichersia coli is a lactose-fermenting, gram-negative bacillus commonly found in the intestines. Salmonella and Shigella are lactose-negative and do not produce red colonies on Endo agar. Proteus is also lactose-negative and doesn't typically grow on Endo agar. Therefore, based on the lactose fermentation and colony color, Escherichia coli is the most likely microorganism present in the fecal sample.

Correct Answer: B

Rationale: The correct answer is B: Cholera. Cholera is caused by Gram-negative curved rod-like bacteria called Vibrio cholerae, commonly found in contaminated water or food. The characteristic symptom of cholera is profuse watery diarrhea, which matches the patient's presentation. Typhoid fever (A) is caused by Salmonella typhi, which is not a curved rod-like bacteria. Diphtheria (C) is caused by Corynebacterium diphtheriae, a Gram-positive bacterium, and does not typically cause diarrhea. Intestinal form of plague (D) is caused by Yersinia pestis, which is not a curved rod-like bacteria and does not typically present with diarrhea.

Correct Answer: A

Rationale: The correct answer is A: spleen. The spleen is not a component of the gastrointestinal tract; it is part of the lymphatic system. The pharynx, esophagus, and stomach are all part of the gastrointestinal tract responsible for digestion and absorption of food. The spleen's main functions include filtering blood, storing blood cells, and supporting the immune system, making it unrelated to the digestive process.

Correct Answer: D

Rationale: The correct answer is D: salmonellosis. Zoonotic diseases are those that can be transmitted from animals to humans. Salmonella is not directly transmitted from animals to humans, instead, it is typically transmitted through contaminated food or water. Brucellosis (A), undulant fever (B), and plague (C) are all zoonotic diseases that can be directly transmitted from animals to humans through various means. Therefore, salmonellosis does not fit the definition of a zoonotic disease, making it the correct answer.

Correct Answer: B

Rationale: The correct answer is B: Legionella and Neisseria are both gram-negative aerobic rods and cocci. Legionella is a rod-shaped bacterium, while Neisseria is a diplococcus. Both are aerobic, meaning they require oxygen for growth. The other choices are incorrect because Legionella and Neisseria are not facultative anaerobes (A), spirochetes (C), or anaerobic cocci (D). Understanding the characteristics of these bacteria helps in differentiating and selecting the correct answer.