Which of the following is not a bacterial antibiotic resistance mechanism
- A. Reduced permeability
- B. Cell-wall regrowth
- C. Over-expression of target
- D. c) Efflux pump
Correct Answer: B
Rationale: The correct answer is B: Cell-wall regrowth. This is not a bacterial antibiotic resistance mechanism because antibiotics target specific components in bacteria, such as cell wall synthesis, making regrowth impossible in the presence of antibiotics. Reduced permeability (A) decreases antibiotic entry, Over-expression of target (C) reduces antibiotic effectiveness, and Efflux pump (D) actively removes antibiotics from the cell, all contributing to antibiotic resistance. In summary, cell-wall regrowth is not a mechanism of antibiotic resistance, unlike the other choices that actively promote bacterial survival against antibiotics.
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An inflammatory disease that can develop as a complication following a group A streptococcal infection is:
- A. endocarditis
- B. rheumatic fever
- C. nephritis
- D. cytomegalovirus
Correct Answer: B
Rationale: The correct answer is B: rheumatic fever. Rheumatic fever is an inflammatory disease that can occur as a complication following a group A streptococcal infection. This is known as a post-streptococcal complication. It typically affects the heart, joints, skin, and brain. Endocarditis (choice A) is also a complication of streptococcal infections, but it is an infection of the heart valves, not an inflammatory disease like rheumatic fever. Nephritis (choice C) is inflammation of the kidneys and is not directly related to streptococcal infections. Cytomegalovirus (choice D) is a different viral infection and is not associated with streptococcal infections.
Which of the following bacteria is a common cause of pneumonia?
- A. Streptococcus pneumoniae
- B. Mycobacterium tuberculosis
- C. Pseudomonas aeruginosa
- D. All of the above
Correct Answer: D
Rationale: The correct answer is D: All of the above.
- Streptococcus pneumoniae is a common cause of community-acquired pneumonia.
- Mycobacterium tuberculosis can cause pulmonary tuberculosis, which can present as pneumonia-like symptoms.
- Pseudomonas aeruginosa is an opportunistic pathogen that can cause pneumonia in immunocompromised individuals.
Therefore, all three bacteria can cause pneumonia, making option D the correct choice. Options A, B, and C are incorrect because they each represent a bacterium that can cause pneumonia, so only selecting one of them would not encompass all common causes of pneumonia.
Slime, blood and protozoa 30-200 microns of length have been revealed in a man's feces. The body is covered with cilias and has correct oval form with a little bit narrowed forward and wide round shaped back end. On the forward end a mouth is visible. In cytoplasm there are two nucleuses and two short vacuoles. For whom are the described attributes typical?
- A. Balantidium
- B. Lamblia
- C. Dysenteric amoeba
- D. Trichomonas
Correct Answer: A
Rationale: Rationale: The described attributes match those of Balantidium. The presence of cilia, oval shape with a narrowed front and wide back end, visible mouth, two nucleuses, and short vacuoles are all characteristic features of Balantidium. Balantidium is a ciliated protozoan parasite commonly found in the human intestine. The other choices can be eliminated based on specific characteristics: Lamblia lacks cilia and has a different shape, Dysenteric amoeba typically has a single nucleus, and Trichomonas does not have cilia or multiple nuclei. Therefore, based on the specific attributes described, the correct answer is Balantidium (Choice A).
Treponemae are motile because of:
- A. axial filaments
- B. mans peritrichous filaments
- C. single monotrichous filament
- D. fimbriae
Correct Answer: A
Rationale: The correct answer is A: axial filaments. Treponemae are motile due to their unique structure of axial filaments, also known as endoflagella. These axial filaments are located within the periplasmic space of the organism and are responsible for the corkscrew-like motility of Treponemae. The other choices (B: mans peritrichous filaments, C: single monotrichous filament, D: fimbriae) do not play a role in the motility of Treponemae. Peritrichous filaments and single monotrichous filaments are not present in Treponemae, and fimbriae are primarily involved in adhesion rather than motility.
Production of auto-antibodies may be due to:
- A. Emergence of mutant clones of B cells
- B. Production of antibodies against hidden tissues
- C. Genetic factors
- D. All of these
Correct Answer: D
Rationale: Production of auto-antibodies can be due to various factors. Mutant B cell clones can lead to the production of self-reactive antibodies. Antibodies against hidden tissues can also trigger autoimmune responses. Genetic factors play a crucial role in predisposing individuals to autoimmunity. Therefore, the correct answer is D, as all these factors can contribute to the production of auto-antibodies. Choice A is incorrect as it only addresses one possible cause. Choice B is incorrect as it focuses solely on antibodies against hidden tissues. Choice C is incorrect as it overlooks the other potential reasons for auto-antibody production.