Nokea
The primary target of beta-lactam antibiotics is:
- A. protein synthesis
- B. DNA replication
- C. cell wall synthesis
- D. folic acid synthesis
Correct Answer: C
Rationale: The primary target of beta-lactam antibiotics is cell wall synthesis. These antibiotics inhibit enzymes called penicillin-binding proteins, which are essential for building the bacterial cell wall. By disrupting cell wall synthesis, beta-lactam antibiotics weaken the cell wall, leading to bacterial cell lysis and death. Protein synthesis (Choice A), DNA replication (Choice B), and folic acid synthesis (Choice D) are not directly targeted by beta-lactam antibiotics, making them incorrect choices.
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Which bacteria are responsible for causing bacterial meningitis?
- A. Neisseria meningitidis
- B. Haemophilus influenzae
- C. Streptococcus pneumoniae
- D. All of the above
Correct Answer: D
Rationale: The correct answer is D, "All of the above." Bacterial meningitis can be caused by Neisseria meningitidis, Haemophilus influenzae, and Streptococcus pneumoniae. These bacteria are common pathogens associated with meningitis. Each of them can lead to serious infections in the brain and spinal cord. Neisseria meningitidis is known for causing meningococcal meningitis, Haemophilus influenzae is a common cause of H. influenzae meningitis, and Streptococcus pneumoniae is responsible for pneumococcal meningitis. Therefore, since all three bacteria can cause bacterial meningitis, the correct answer is D. Choices A, B, and C are incorrect because each of these bacteria individually can cause bacterial meningitis; it is not limited to just one specific type.
Pili are also called:
- A. fimbriae
- B. microvilli
- C. cilia
- D. flagella
Correct Answer: B
Rationale: The correct answer is B: microvilli. Pili are hair-like structures found on the surface of some bacteria, while microvilli are microscopic cellular projections that increase surface area for absorption in cells like intestinal cells. Pili are involved in bacterial adhesion, while microvilli are important for nutrient absorption. Therefore, the correct answer is B.
Incorrect choices:
A: Fimbriae are short, thin appendages found on the surface of some bacteria, mainly used for adhesion.
C: Cilia are hair-like structures found on the surface of some eukaryotic cells, often involved in movement or sensory functions.
D: Flagella are long, whip-like appendages used for bacterial motility.
The most important fungi that cause diseases of the skin, hair, and nails are called:
- A. Plasmodium
- B. sporozoites
- C. dermatophytes
- D. nematodes
Correct Answer: C
Rationale: Correct Answer: C: dermatophytes
Rationale:
1. Dermatophytes are fungi that specifically infect the skin, hair, and nails.
2. They are the most common fungi causing such infections in humans.
3. Plasmodium and sporozoites are parasites causing malaria, not skin diseases.
4. Nematodes are a type of roundworm and do not typically cause skin, hair, or nail infections.
In summary, dermatophytes are the correct answer because they are specialized fungi that commonly cause skin, hair, and nail diseases, distinguishing them from the other choices.
A 37-year-old male was admitted to a hospital complaining of abdominal pain, difficulty in swallowing and breathing, constipation, and nausea. He developed respiratory failure and required endotracheal intubation and ventilation. Two days before, the patient consumed dried salted fish bought from an artisanal producer. Laboratory investigation for infectious pathogen was performed using Kitt-Tarozzi's method. Observation under a bright field microscopy revealed the presence of typical microorganisms with tennis racket appearance. Which of the following is the most likely diagnosis?
- A. Botulism
- B. Cholera
- C. Nontyphoidal Salmonella infection
- D. Typhoid fever
Correct Answer: A
Rationale: The correct answer is A: Botulism. Botulism is caused by the toxin produced by Clostridium botulinum bacteria found in improperly preserved or canned foods. The symptoms described align with botulism, such as difficulty swallowing and breathing due to muscle paralysis. The tennis racket appearance seen under microscopy corresponds to the characteristic appearance of Clostridium botulinum spores. The other choices can be ruled out based on the clinical presentation and microscopy findings. Cholera typically presents with severe watery diarrhea, Nontyphoidal Salmonella infection with fever and gastrointestinal symptoms, and Typhoid fever with high fever and abdominal pain. Therefore, the most likely diagnosis in this case is botulism.
Rheumatic fever is usually a complication of a(n) __________ infection.
- A. Escherichia coli
- B. Streptococcus pyogenes
- C. Staphylococcus epidermidis
- D. Staphylococcus aureus
Correct Answer: B
Rationale: Rationale:
1. Streptococcus pyogenes is the causative agent of strep throat.
2. If untreated, strep throat can lead to rheumatic fever.
3. Rheumatic fever is an autoimmune complication of streptococcal infections.
4. E. coli, S. epidermidis, and S. aureus are not typically associated with rheumatic fever.