Nokea
Microscopy of a smear obtained from a patient with acute purulent periostitis revealed gram-positive bacteria arranged in clusters resembling bunch of grapes. What microorganisms is this morphology typical for?
- A. Staphylococci
- B. Sarcina
- C. Tetracocci
- D. Candida fungi
Correct Answer: A
Rationale: Rationale:
Staphylococci are gram-positive bacteria that typically arrange in clusters resembling a bunch of grapes. This characteristic morphology is specific to staphylococci due to their division pattern. Sarcina, Tetracocci, and Candida fungi do not exhibit this clustering pattern. Staphylococci are commonly associated with purulent infections, making them the most likely microorganisms in this scenario.
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In order to prevent wound infection associated with surgical procedures a patient was given a synthetic antiprotozoan drug with a high activity against Helicobacter pylori. Specify this drug:
- A. Metronidazole
- B. Doxycycline hydrochloride
- C. Chingamin
- D. Acyclovir
Correct Answer: A
Rationale: The correct answer is A: Metronidazole. Metronidazole is a synthetic antiprotozoan drug with high activity against Helicobacter pylori, a bacterium that can cause wound infections. Metronidazole specifically targets anaerobic bacteria like H. pylori, making it effective in preventing wound infections.
Incorrect choices:
B: Doxycycline hydrochloride - Doxycycline is primarily used for bacterial infections, not protozoan infections like H. pylori.
C: Chingamin - Chingamin is not a commonly used drug for treating H. pylori infections or preventing wound infections.
D: Acyclovir - Acyclovir is an antiviral drug used to treat herpes infections, not bacterial or protozoan infections like H. pylori.
Which fact is correct about the nucleoids in bacteria:
- A. Contain a haploid bacterial chromosomes in each nucleus
- B. Are reabsorbed well by the method of Neisser
- C. Are 1 to 4 in each bacterial cell depending on the nature of the cell and the phases of growth and replication
- D. None of the above
Correct Answer: C
Rationale: The correct answer is C because nucleoids in bacteria can vary in number from 1 to 4 depending on the specific bacterial cell and its growth and replication phases. This is due to the dynamic nature of bacterial cells and their genetic material organization.
Choice A is incorrect because nucleoids do not contain nuclear membranes or multiple haploid chromosomes like eukaryotic nuclei. Choice B is incorrect as there is no known method of reabsorbing nucleoids by Neisser. Choice D is incorrect as option C is indeed the correct statement regarding the number of nucleoids in bacterial cells.
A child with diarrhea had stool microscopy revealing cysts with four nuclei. What is the most likely causative agent?
- A. Entamoeba histolytica
- B. Giardia lamblia
- C. Balantidium coli
- D. Trichomonas hominis
Correct Answer: A
Rationale: The correct answer is A: Entamoeba histolytica. This pathogen is known to cause amoebic dysentery, characterized by diarrhea with bloody or mucoid stools. The presence of cysts with four nuclei in the stool microscopy is a characteristic feature of Entamoeba histolytica. Other choices are incorrect because Giardia lamblia typically presents with binucleate cysts, Balantidium coli is a ciliated protozoan, and Trichomonas hominis is a non-pathogenic parasite found in the human intestine.
The prokaryotic cell does not possess:
- A. Ribosomes
- B. Endoplasmic reticulum
- C. Chromosome
- D. Peptidoglycan
Correct Answer: B
Rationale: The correct answer is B: Endoplasmic reticulum. Prokaryotic cells lack membrane-bound organelles like the endoplasmic reticulum, which is present in eukaryotic cells. Prokaryotes do possess ribosomes for protein synthesis (A), a chromosome (C) for genetic material, and peptidoglycan (D) in their cell walls. The absence of endoplasmic reticulum is a key characteristic that distinguishes prokaryotic cells from eukaryotic cells.
A patient complains of frequent bowel movements and stool with blood admixtures ("raspberry jelly" stool). Microscopic examination revealed large mononuclear cells with absorbed red blood cells. What protozoon is this morphological structure typical for?
- A. Entamoeba histolytica
- B. Giardia lamblia
- C. Campylobacter jejuni
- D. Toxoplasma gondii
Correct Answer: A
Rationale: The correct answer is A: Entamoeba histolytica. This protozoon is responsible for causing amoebic dysentery, which presents with bloody diarrhea. The "raspberry jelly" appearance of stool is due to the presence of mucosal lining and blood. The large mononuclear cells with absorbed red blood cells are characteristic of the histopathology of Entamoeba histolytica infection. Giardia lamblia (B) causes watery diarrhea, not bloody stools. Campylobacter jejuni (C) is a bacterial pathogen associated with gastroenteritis, but does not typically cause bloody diarrhea. Toxoplasma gondii (D) causes toxoplasmosis, a systemic infection with symptoms such as fever and lymphadenopathy, but not bloody diarrhea.