Nokea
Complement fixation test
- A. Is done in three stages
- B. Is a test that can be used to detect the presence of either specific antibody or specific antigen in a patient's serum
- C. Is done with human, not standardized complement proteins
- D. Can be made with or without sheep red blood cells
Correct Answer: B
Rationale: The correct answer is B because the complement fixation test is a serological test that detects the presence of specific antibodies or antigens in a patient's serum. It works by measuring the ability of antibodies to fix complement proteins. Choice A is incorrect because the complement fixation test typically involves several steps, not necessarily three. Choice C is incorrect as standardized complement proteins are commonly used in this test. Choice D is incorrect because sheep red blood cells are not essential for performing the complement fixation test.
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The main function of siderophores in bacteria is:
- A. to enhance antibiotic resistance
- B. to sequester iron from the environment
- C. to form capsules
- D. to perform oxidative phosphorylation
Correct Answer: B
Rationale: The correct answer is B: to sequester iron from the environment. Siderophores are molecules produced by bacteria to chelate and acquire iron, an essential nutrient for their growth and survival. By sequestering iron, bacteria can compete with host cells and other microbes for this vital resource. This enhances their ability to thrive and establish infections. Choices A, C, and D are incorrect because siderophores do not directly enhance antibiotic resistance, form capsules, or perform oxidative phosphorylation. These functions are unrelated to the primary role of siderophores in iron acquisition.
The role of adhesins in gram positive bacteria is carried out by:
- A. Lipoteichoic acids
- B. Fimbriae
- C. Flagella
- D. Short chain mycolic chains
Correct Answer: A
Rationale: Adhesins in gram positive bacteria are typically carried out by surface structures such as lipoteichoic acids. These molecules help the bacteria adhere to host cells or tissues. Lipoteichoic acids are specific to gram positive bacteria and play a crucial role in initiating infections. Fimbriae, flagella, and short chain mycolic acids are not primarily responsible for adhesion in gram positive bacteria. Fimbriae are more commonly found in gram negative bacteria, flagella are involved in motility, and short chain mycolic acids are specific to mycobacteria. Therefore, the correct answer is A, lipoteichoic acids.
A gynaecologist was examining a patient and revealed symptoms of genital tract inflammation. A smear from vagina contains pyriform protozoa with a spine, flagella at their front; there is also an undulating membrane. What disease can be suspected?
- A. Urogenital trichomoniasis
- B. Lambliasis
- C. Intestinal trichomoniasis
- D. Toxoplasmosis
Correct Answer: A
Rationale: The correct answer is A: Urogenital trichomoniasis. The presence of pyriform protozoa with a spine, flagella at their front, and an undulating membrane in a vaginal smear indicates Trichomonas vaginalis, the causative agent of urogenital trichomoniasis. Trichomonas vaginalis is sexually transmitted and causes vaginal discharge, itching, and inflammation. Lambliasis (choice B) is caused by Giardia lamblia, which is not characterized by the described features. Intestinal trichomoniasis (choice C) is caused by a different species, Tritrichomonas foetus, and presents with diarrhea in cattle. Toxoplasmosis (choice D) is caused by Toxoplasma gondii and typically affects the brain and other organs, not the genital tract.
Which of the following bacteria is responsible for causing peptic ulcers?
- A. Escherichia coli
- B. Helicobacter pylori
- C. Streptococcus pyogenes
- D. Mycobacterium tuberculosis
Correct Answer: B
Rationale: The correct answer is B: Helicobacter pylori. This bacterium is known to be the primary cause of peptic ulcers by colonizing the stomach lining and causing inflammation. It produces urease enzyme to neutralize stomach acid and has a flagellum for mobility. Escherichia coli (A) is mainly associated with foodborne illnesses. Streptococcus pyogenes (C) causes strep throat and skin infections. Mycobacterium tuberculosis (D) causes tuberculosis, a respiratory infection. Therefore, Helicobacter pylori is the correct choice for peptic ulcers based on its unique characteristics and pathogenicity.
For serological diagnostics of the whooping cough it was made large-scale reaction with parapertussis and pertussis diagnosticums. At the bottom of the test-tubes with diagnosticum of Bordetella parapertussis grain-like sediment formed. What antibodies have this reaction revealed?
- A. Bacteriolysins
- B. Precipitins
- C. Antitoxins
- D. Opsonins
Correct Answer: B
Rationale: Rationale:
1. The grain-like sediment indicates a precipitation reaction.
2. Precipitins are antibodies that cause precipitation reactions.
3. In serological diagnostics, precipitation reactions are used to detect specific antibodies.
4. Therefore, the reaction revealed in this scenario is due to the presence of precipitins.
Summary:
A: Bacteriolysins - These antibodies cause bacterial lysis, not precipitation.
C: Antitoxins - These antibodies neutralize toxins, not involved in precipitation reactions.
D: Opsonins - These antibodies enhance phagocytosis, not related to precipitation reactions.