Nokea
A patient with fever, headache, and neck stiffness had cerebrospinal fluid microscopy revealing Gram-negative diplococci. What is the likely causative agent?
- A. Neisseria meningitidis
- B. Streptococcus pneumoniae
- C. Haemophilus influenzae
- D. Klebsiella pneumoniae
Correct Answer: A
Rationale: The correct answer is A: Neisseria meningitidis. This bacterium is a Gram-negative diplococcus commonly associated with meningitis. Neisseria meningitidis is a leading cause of bacterial meningitis in young adults and adolescents. It is known for causing fever, headache, and neck stiffness. The other choices, Streptococcus pneumoniae, Haemophilus influenzae, and Klebsiella pneumoniae, are not typically Gram-negative diplococci and are not commonly associated with the symptoms described. Streptococcus pneumoniae is a Gram-positive coccus, Haemophilus influenzae is a Gram-negative coccobacillus, and Klebsiella pneumoniae is a Gram-negative rod. Therefore, Neisseria meningitidis is the most likely causative agent in this scenario.
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Microscopic examination of a microbial culture revealed fusiform spore-forming microorganisms that get violet-blue Gram's stain. What microorganisms were revealed?
- A. Clostridia
- B. Streptococci
- C. Spirochaete
- D. Actinomycete
Correct Answer: A
Rationale: The correct answer is A: Clostridia. Fusiform spore-forming microorganisms that stain violet-blue with Gram's stain are characteristic of Clostridia. Clostridia are anaerobic, rod-shaped bacteria known for their ability to form spores and cause diseases such as tetanus and botulism.
Summary of other choices:
B: Streptococci are spherical, not fusiform, and typically do not form spores.
C: Spirochaete are spiral-shaped bacteria and do not typically form spores.
D: Actinomycete are filamentous bacteria that do not typically form spores and do not stain violet-blue with Gram's stain.
A child cut his leg with a piece of glass while playing and was brought to the clinic for the injection of tetanus toxoid. In order to prevent the development of anaphylactic shock the serum was administered by Bezredka method. What mechanism underlies this method of desensitization of the body?
- A. Binding of IgE fixed to the mast cells
- B. Blocking the mediator synthesis in the mast cells
- C. Stimulation of immune tolerance to the antigen
- D. Stimulation of the synthesis of antigenspecific IgG
Correct Answer: A
Rationale: The correct answer is A: Binding of IgE fixed to the mast cells. The Bezredka method involves injecting small, gradually increasing doses of the antigen (tetanus toxoid) to desensitize the body and prevent anaphylactic shock. This process works by binding the IgE antibodies fixed to mast cells, thereby reducing the release of allergic mediators like histamine. This prevents the cascade of events that lead to anaphylactic shock.
Choice B (Blocking the mediator synthesis in the mast cells) is incorrect because the Bezredka method does not block mediator synthesis but rather prevents the release of mediators by binding IgE.
Choice C (Stimulation of immune tolerance to the antigen) is incorrect as the Bezredka method does not primarily focus on inducing immune tolerance but rather on preventing anaphylactic reactions.
Choice D (Stimulation of the synthesis of antigen-specific IgG) is incorrect because the Bezredka method targets IgE antibodies on mast cells
Which of the following infections are typical for the upper respiratory tract?
- A. Psittacosis
- B. Mycoplasma bronchitis
- C. Chronic atrophic rhinitis
- D. Legionnaires disease
Correct Answer: C
Rationale: The correct answer is C: Chronic atrophic rhinitis. This infection is typical for the upper respiratory tract as it affects the nasal mucosa and sinuses. It is characterized by inflammation and atrophy of the nasal mucosa. Psittacosis (A) is a zoonotic infection transmitted from birds, affecting the lungs. Mycoplasma bronchitis (B) is a lower respiratory tract infection caused by Mycoplasma pneumoniae. Legionnaires disease (D) is a severe form of pneumonia caused by Legionella bacteria. Therefore, C is the correct answer as it specifically pertains to the upper respiratory tract.
A duodenal content smear of a patient with indigestion contains protozoa 10-18 mcm large. They have piriform bodies, 4 pairs of filaments, two symmetrically located nuclei in the broadened part of body. What kind of the lowest organisms is it?
- A. Lamblia
- B. Dysentery ameba
- C. Trichomonas
- D. Intestinal ameba
Correct Answer: A
Rationale: The correct answer is A: Lamblia. The description matches the characteristics of Giardia lamblia - a protozoan parasite that causes giardiasis. The piriform bodies, 4 pairs of filaments, and two symmetrically located nuclei are specific to Giardia lamblia. It is important to differentiate it from the other choices. Dysentery ameba (choice B) typically has a single nucleus and lacks the specific characteristics described. Trichomonas (choice C) is a flagellated protozoan with different morphology and does not match the given description. Intestinal ameba (choice D) such as Entamoeba histolytica usually has a single nucleus and different body shape compared to the described organism.
The main structure components of Viruses are:
- A. Glycoproteins and proteins
- B. Nucleic acids and lipids
- C. Nucleic acid and proteins
- D. Lipids and proteins
Correct Answer: C
Rationale: The correct answer is C: Nucleic acid and proteins. Viruses contain genetic material in the form of nucleic acids (DNA or RNA) surrounded by a protein coat. This genetic material carries instructions for viral replication. Proteins are also essential components of viruses, serving various functions like facilitating viral entry into host cells. Option A is incorrect as lipids are not main components of viruses. Option B is incorrect as lipids are not typically found in the main structure of viruses. Option D is incorrect as lipids are not primary components of viruses, and glycoproteins are not always present in the main structure of viruses.