ATI RN
Microbiology A Systems Approach Test Bank Questions
Question 1 of 4
A patient complains of acute spastic abdominal pain, frequent urge to defecate, liquid bloody feces with mucus. Laboratory analysis of fecal smear revealed inconstant in shape organisms with erythrocyte. What is the most likely diagnosis?
Correct Answer: A
Rationale: The correct answer is A: Amebiasis. Amebiasis is caused by the parasite Entamoeba histolytica, presenting with symptoms like acute abdominal pain, bloody diarrhea with mucus, and inconstant shape organisms seen in fecal smear. The presence of erythrocytes supports the diagnosis due to the parasite's ability to invade intestinal mucosa causing bleeding. Choice B (Lambliasis) presents with different symptoms like steatorrhea and fatigue. Choice C (Schistosomiasis) is mainly associated with liver and urinary symptoms. Choice D (Intestinal trichomoniasis) commonly presents with watery diarrhea and does not typically cause bloody stools. Therefore, based on the patient's symptoms and fecal smear findings, Amebiasis is the most likely diagnosis.
Question 2 of 4
A 40 year old man noticed a reddening and an edema of skin in the area of his neck that later developed into a small abscess. The incised focus is dense, yellowish-green. The pus contains white granules. Histological examination revealed drusen of a fungus, plasmatic and xanthome cells, macrophages. What type of mycosis is the most probable?
Correct Answer: D
Rationale: The correct answer is D: Sporotrichosis. Sporotrichosis is caused by the fungus Sporothrix schenckii, which commonly presents as a subcutaneous infection. In the given case, the presence of a small abscess with yellowish-green pus containing white granules is indicative of sporotrichosis. The histological examination showing drusen of a fungus, plasmatic and xanthome cells, and macrophages further supports the diagnosis of sporotrichosis. Choice A: Actinomycosis is a bacterial infection caused by Actinomyces species, not a fungal infection. Choice B: Aspergillosis is caused by Aspergillus species and typically presents as a pulmonary infection, not a subcutaneous abscess as described in the case. Choice C: Candidosis is caused by Candida species and usually presents as mucocutaneous infections, not a subcutaneous abscess with the
Question 3 of 4
A man uses dentures. The dentist has noticed mucosal lecions with a white coating in his oral cavity. Microscopy of the coating detected large oval Gram-positive cells. What microorganisms have caused stomatitis in the patient?
Correct Answer: A
Rationale: The correct answer is A: Yeast-like fungi of Candida genus. Candida is a common cause of oral thrush/stomatitis, characterized by mucosal lesions with white coating. The presence of large oval Gram-positive cells is indicative of Candida species. Actinomycetes (B) are filamentous bacteria and not oval Gram-positive cells. Streptococci (C) are spherical bacteria, not oval, and are not commonly associated with stomatitis. Oral spirochetes (D) are spiral-shaped bacteria and not oval Gram-positive cells typically seen in Candida infections. Thus, A is the correct choice based on the characteristic morphology and clinical presentation.
Question 4 of 4
Basing upon the data of laboratory assessment of sanitary state of soil in a certain territory, the soil was found to be low-contaminated according to the sanitary indicative value; contaminated according to the coli titer; low-contaminated according to the anaerobe titer (Cl. perfringens). This is indicative of:
Correct Answer: A
Rationale: Step 1: The soil is low-contaminated according to the sanitary indicative value, which indicates that the contamination is recent. Step 2: The soil is contaminated according to coli titer, suggesting the presence of coliform bacteria typically found in fresh fecal matter. Step 3: The soil is low-contaminated according to the anaerobe titer (Cl. perfringens), which is an indicator of recent fecal contamination. Step 4: Based on the above steps, the correct answer is A: Fresh fecal contamination, as the presence of coliform bacteria and recent anaerobe titer levels point to recent fecal contamination. Summary: B: Old fecal contamination - Incorrect because the indicators suggest recent contamination. C: Insufficient intensity of soil humification - Incorrect as it is not related to the specific indicators mentioned in the question. D: Constant entry of organic protein contaminations - Incorrect as the indicators point towards fecal contamination, not protein