Nokea
The immunity in syphilis is:
- A. Nonsterile (infectious)
- B. Antitoxic
- C. Humoral
- D. A + B + C
Correct Answer: A
Rationale: The correct answer is A because immunity in syphilis is nonsterile, meaning that individuals who have been infected may still carry the bacteria and be capable of transmitting the disease. This is due to the ability of the bacterium causing syphilis, Treponema pallidum, to evade the immune system by hiding within host cells.
Option B, antitoxic, is incorrect because syphilis is not caused by a toxin produced by the bacteria, but rather by the bacterium itself.
Option C, humoral, is also incorrect as syphilis immunity involves both humoral (antibody-mediated) and cell-mediated immune responses, not solely humoral immunity.
Option D is incorrect as it includes all three options, whereas in reality, the immunity in syphilis is primarily nonsterile.
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A child with fever and swollen lymph nodes had a Gram-stained smear revealing Gram-negative rods with a safety pin appearance. What is the causative agent?
- A. Yersinia pestis
- B. Francisella tularensis
- C. Brucella abortus
- D. Clostridium botulinum
Correct Answer: A
Rationale: The correct answer is A: Yersinia pestis. This bacterium causes the plague, which presents with fever and swollen lymph nodes. The safety pin appearance on Gram stain is characteristic of Yersinia pestis.
B: Francisella tularensis causes tularemia, which presents differently and does not show safety pin appearance on Gram stain.
C: Brucella abortus causes brucellosis, which does not typically present with the same symptoms as described in the question.
D: Clostridium botulinum causes botulism, which does not show safety pin appearance on Gram stain and does not typically present with fever and swollen lymph nodes.
Specify the FALSE statement. Bacteriocins:
- A. Kill the bacterial cells of closely related species
- B. Are substances with protein nature
- C. Are polysaccharides of varying activity
- D. Kill the bacteria cells of other strains of the same species
Correct Answer: C
Rationale: The correct answer is C because bacteriocins are substances with protein nature, not polysaccharides. Bacteriocins are antimicrobial peptides that kill bacterial cells, mainly those of closely related species or other strains of the same species. Polysaccharides are not typically involved in bacteriocin activity. Therefore, option C is false. Options A, B, and D are true statements supported by the nature and function of bacteriocins.
Which bacteria are capable of forming spores to survive in harsh environments?
- A. Bacillus anthracis
- B. Clostridium botulinum
- C. Both A and B
- D. None of the above
Correct Answer: C
Rationale: The correct answer is C (Both A and B) because both Bacillus anthracis and Clostridium botulinum are capable of forming spores to survive in harsh environments. Bacillus anthracis causes anthrax and forms spores that can survive extreme conditions. Clostridium botulinum causes botulism and also forms spores for survival. Option A (Bacillus anthracis) and Option B (Clostridium botulinum) are incorrect on their own because they only represent one of the bacteria capable of forming spores. Option D (None of the above) is incorrect because it disregards the fact that both bacteria can form spores.
Which one of the following is a normal skin flora?
- A. Streptococcus pyogenes
- B. Staphylococcus epidermidis
- C. Pseudomonas aeruginosa
- D. Acinetobacter baumannii
Correct Answer: B
Rationale: The correct answer is B: Staphylococcus epidermidis. This bacterium is a normal skin flora commonly found on human skin. It is part of the skin microbiota and helps protect against pathogenic organisms. Streptococcus pyogenes (A), Pseudomonas aeruginosa (C), and Acinetobacter baumannii (D) are not normal skin flora. Streptococcus pyogenes is a pathogenic bacterium causing various infections, Pseudomonas aeruginosa is an opportunistic pathogen commonly found in water and soil, and Acinetobacter baumannii is associated with healthcare-associated infections.
The neonatal infection referred to as “sticky eye†is caused by:
- A. Streptococcus
- B. herpes simplex
- C. Staphylococcus
- D. Escherichia
Correct Answer: C
Rationale: The correct answer is C: Staphylococcus. Staphylococcus is a common bacteria that can cause neonatal conjunctivitis, also known as "sticky eye." Staphylococcal conjunctivitis presents with symptoms like eye redness, discharge, and swelling. Streptococcus (choice A) typically causes throat infections, herpes simplex (choice B) causes genital or oral sores, and Escherichia (choice D) is a bacteria commonly found in the gastrointestinal tract and is not typically associated with neonatal conjunctivitis. Therefore, the most likely pathogen causing "sticky eye" in newborns is Staphylococcus.