Acne is caused by:
- A. Staphylococcus aureus
- B. Staphylococcus epidermidis
- C. Streptococcus pyogenes
- D. Propionibacterium acnes
Correct Answer: D
Rationale: The correct answer is D: Propionibacterium acnes. This bacterium plays a key role in acne formation by colonizing hair follicles, leading to inflammation and acne lesions. It produces fatty acids that contribute to the development of acne. Staphylococcus aureus (A) and Staphylococcus epidermidis (B) are not directly linked to acne. Streptococcus pyogenes (C) is associated with skin infections but not acne. In summary, Propionibacterium acnes is the primary bacterium responsible for acne due to its ability to induce inflammation and follicular blockages.
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The correct hierarchical order for virus classification is
- A. order, genus, family, subfamily, species.
- B. species, genus, family, subfamily, order.
- C. order, family, subfamily, genus, species.
- D. genus, order, family, subfamily, species.
Correct Answer: C
Rationale: The correct hierarchical order for virus classification is order, family, subfamily, genus, species. This is because classification starts at a broader level (order) and narrows down to a more specific level (species). Order comes first to group viruses based on common characteristics, followed by family, which further categorizes them. Subfamily refines the classification, then genus groups similar viruses together, and species distinguishes different strains within a genus. Choice A is incorrect because it places genus before family, which is not the correct sequence. Choice B is incorrect as it starts with species, which is the most specific level. Choice D is incorrect because it places genus at the beginning, which is too specific for the hierarchical order.
The class of immunoglobulins most abundant in body is:
- A. IgG
- B. IgE
- C. IgD
- D. IgM
Correct Answer: A
Rationale: The correct answer is A: IgG. IgG is the most abundant class of immunoglobulins in the body, constituting about 75% of total immunoglobulins. IgG plays a crucial role in long-term immunity, neutralizing toxins, and enhancing phagocytosis. IgE is involved in allergic reactions, IgD is mainly found on B cells and functions as a receptor, and IgM is the first antibody produced in response to an infection but is less abundant compared to IgG. Therefore, IgG is the correct choice based on its abundance and diverse functions in the immune system.
Which of the antibiotics listed below are not suitable for treatment of listeriosis?
- A. Penicillin and ampicillin
- B. Macrolids
- C. Cephalosporins
- D. None of them
Correct Answer: B
Rationale: The correct answer is B: Macrolides. Listeriosis is typically treated with antibiotics such as Penicillin and ampicillin due to their effectiveness against Listeria monocytogenes. Macrolides, on the other hand, are not first-line agents for listeriosis treatment. They are less effective in treating this bacterial infection compared to Penicillin and ampicillin. Cephalosporins may also be less effective against Listeria monocytogenes compared to Penicillin and ampicillin. Choice D is incorrect as Macrolides are not suitable for listeriosis treatment.
A 14-year-old patient was diagnosed with Hutchinson's triad: barrel-shaped incisors, parenchymatous keratitis and deafness. The revealed presentations are consistent with the following disease:
- A. Syphilis
- B. Toxoplasmosis
- C. Lepra
- D. Tuberculosis
Correct Answer: A
Rationale: The correct answer is A: Syphilis. Hutchinson's triad is a classic presentation of congenital syphilis in children. Barrel-shaped incisors, parenchymatous keratitis, and deafness are key manifestations. Barrel-shaped incisors result from mulberry molars, a type of abnormal tooth. Parenchymatous keratitis is an inflammation of the cornea, a common ocular sign in congenital syphilis. Deafness can occur due to damage to the auditory nerve caused by the infection. Choices B, C, and D are incorrect as they do not typically present with the specific triad of symptoms seen in congenital syphilis.
A pregnant woman applied to a doctor with complaints typical for toxoplasmosis. The doctor took a sample of her blood. What serological tests should be performed in this case?
- A. Complement binding assay
- B. Precipitation test
- C. Neutralization test
- D. Widal's test
Correct Answer: A
Rationale: The correct serological test for diagnosing toxoplasmosis is the Complement Binding Assay (A) because it detects antibodies specific to the Toxoplasma gondii parasite. This test is highly sensitive and specific for toxoplasmosis.
Choice B, Precipitation test, is not used for toxoplasmosis diagnosis but rather for other diseases like syphilis.
Choice C, Neutralization test, is not specific for toxoplasmosis and is used for other types of infections.
Choice D, Widal's test, is used for diagnosing typhoid fever and is not relevant for toxoplasmosis.
In summary, the correct answer (A) is specific to toxoplasmosis, while the other choices are used for different diseases and are not suitable for diagnosing toxoplasmosis.
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