Nokea
A patient with diarrhea had fecal analysis revealing small, curved Gram-negative bacilli with a monotrichous flagellum. These bacteria do not form spores or capsules and thrive in alkaline conditions. What is the causative agent?
- A. Vibrio cholerae
- B. Escherichia coli
- C. Salmonella
- D. Shigella
Correct Answer: A
Rationale: Step 1: Small, curved Gram-negative bacilli with a monotrichous flagellum point towards a motile bacterium.
Step 2: The absence of spores or capsules and preference for alkaline conditions further narrows down the possibilities.
Step 3: Vibrio cholerae fits all criteria as it is a curved, motile, Gram-negative bacillus that thrives in alkaline environments.
Summary: Escherichia coli is a facultative anaerobe, Salmonella and Shigella are non-flagellated, and all of them can form capsules or spores, unlike Vibrio cholerae.
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The tertiary stage of syphilis is usually manifested as:
- A. Syphilitic granulomas (gummas)
- B. Purulent exudation from the urethra
- C. Non-tender chancre (ulcus durum)
- D. Diffuse maculopapular rash
Correct Answer: A
Rationale: The correct answer is A: Syphilitic granulomas (gummas). In the tertiary stage of syphilis, gummas, which are soft, tumor-like growths, can develop in various organs such as the skin, bones, liver, and brain. This stage typically occurs years after the initial infection and can lead to serious complications if left untreated. Purulent exudation from the urethra (B) is not specific to syphilis and may indicate other infections. Non-tender chancre (C) is characteristic of the primary stage of syphilis, not the tertiary stage. Diffuse maculopapular rash (D) is more commonly seen in the secondary stage of syphilis.
A sputum sample from a patient with pneumonia revealed Gram-positive cocci in pairs with a capsule. What is the most likely causative agent?
- A. Streptococcus pneumoniae
- B. Staphylococcus aureus
- C. Klebsiella pneumoniae
- D. Pseudomonas aeruginosa
Correct Answer: A
Rationale: The correct answer is A: Streptococcus pneumoniae. This bacterium is the most likely causative agent for pneumonia in this case due to the presence of Gram-positive cocci in pairs with a capsule, which is a typical characteristic of S. pneumoniae. This pathogen is a common cause of community-acquired pneumonia and is known for its encapsulated morphology. Staphylococcus aureus (B) is a Gram-positive cocci but does not typically present in pairs with a capsule in pneumonia cases. Klebsiella pneumoniae (C) is a Gram-negative bacterium and does not match the description provided. Pseudomonas aeruginosa (D) is a Gram-negative bacterium that is not typically associated with Gram-positive cocci in pneumonia samples.
Micellar growth
- A. is observed in bacterial cells
- B. includes a parent and daughter cell which have different sizes
- C. is inherent in viruses and rickettsia
- D. represents apical prolongation of the hyphae in the fungus
Correct Answer: D
Rationale: Step 1: Micellar growth refers to the apical prolongation of hyphae in fungi.
Step 2: Fungi have a unique growth structure with hyphae extending at the tips.
Step 3: This growth pattern allows fungi to expand and access nutrients.
Step 4: Bacterial cells (A) do not exhibit micellar growth.
Step 5: Parent and daughter cells in division have similar sizes, not different (B).
Step 6: Viruses and rickettsia (C) do not display micellar growth.
A 10-year-old child had the mantoux tuberculin test administered. 48 hours later a papule up to 8 mm in diameter appeared on the site of the injection. What type of hypersensitivity reaction developed after the tuberculin injection?
- A. Type IV hypersensitivity reaction
- B. Arthus phenomenon
- C. Seroreaction
- D. Type II hypersensitivity reaction
Correct Answer: A
Rationale: The correct answer is A: Type IV hypersensitivity reaction. This type of reaction is characterized by a delayed response involving T cells. In this case, the appearance of a papule after 48 hours indicates a delayed hypersensitivity reaction, which is typical of a Type IV reaction. The other choices are incorrect because: B: Arthus phenomenon is a localized immune complex-mediated reaction, not seen in tuberculin tests. C: Seroreaction typically involves antibodies reacting with soluble antigens, not seen in this scenario. D: Type II hypersensitivity reactions involve antibodies targeting specific cells or tissues, which is not the mechanism at play in this case.
On the base of the clinical data a child was diagnosed with atypical pneumonia resistant to the effects of beta-lactam antibiotics. The patient's sputum was cultured and incubated in a special medium, which resulted in growth of microorganisms forming microscopic colonies with a dense center (looking like fried eggs). What microorganism caused the disease?
- A. Mycoplasma pneumoniae
- B. Klebsiella pneumoniae
- C. Str. pneumoniae
- D. L. pneumophila
Correct Answer: A
Rationale: The correct answer is A: Mycoplasma pneumoniae. Mycoplasma pneumoniae is a common cause of atypical pneumonia and is known to be resistant to beta-lactam antibiotics. The description of microorganisms forming microscopic colonies with a dense center resembling fried eggs is characteristic of Mycoplasma pneumoniae colonies seen on special media.
Summary of other choices:
B: Klebsiella pneumoniae is not typically associated with atypical pneumonia and does not exhibit the described colony morphology.
C: Streptococcus pneumoniae is not resistant to beta-lactam antibiotics and does not produce colonies with the described appearance.
D: Legionella pneumophila is associated with Legionnaires' disease, not atypical pneumonia, and does not form colonies resembling fried eggs.