Nokea
Disinfection with chemicals acting on cell surface:
- A. Soaps
- B. Phenols
- C. Amines
- D. Polymyxin
Correct Answer: B
Rationale: The correct answer is B: Phenols. Phenols act on the cell surface by disrupting cell membranes and denaturing proteins, leading to cell death. Soaps (A) work by lifting dirt and microbes off surfaces, not directly acting on cell surfaces. Amines (C) are typically used as disinfectants targeting specific enzymes in microbes, not cell surfaces. Polymyxin (D) is an antibiotic that works by disrupting cell membranes internally, not on the cell surface.
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Which bacteria are associated with causing foodborne infections?
- A. Clostridium botulinum
- B. Escherichia coli
- C. Salmonella enterica
- D. All of the above
Correct Answer: D
Rationale: The correct answer is D (All of the above) because all three bacteria (Clostridium botulinum, Escherichia coli, Salmonella enterica) are known to cause foodborne infections. Clostridium botulinum can lead to botulism, E. coli can cause various gastrointestinal illnesses, and Salmonella enterica is a common cause of food poisoning. Each bacterium has specific mechanisms that result in foodborne illnesses. Choices A, B, and C are incorrect because each bacterium mentioned is associated with causing foodborne infections, making them collectively the correct answer.
An 18-year-old patient has enlarged inguinal lymph nodes, they are painless, thickened on palpation. In the area of genital mucous membrane there is a small-sized ulcer with thickened edges and "laquer"bottom of greyish colour. What is the most probable diagnosis?
- A. Syphilis
- B. Tuberculosis
- C. Lepra
- D. Trophic ulcer
Correct Answer: A
Rationale: The correct answer is A: Syphilis. The presentation of painless inguinal lymph nodes, along with a small-sized ulcer with thickened edges and a "laquer" bottom of greyish color on the genital mucous membrane, is classic for primary syphilis. The painless nature of the lymph nodes and the specific characteristics of the ulcer are key features of syphilitic infection. Primary syphilis is caused by the bacterium Treponema pallidum and typically presents with a single, painless ulcer known as a chancre. It is important to consider syphilis in the differential diagnosis of genital ulcers.
Summary of other choices:
B: Tuberculosis - Unlikely, as tuberculosis typically presents with pulmonary symptoms and does not cause genital ulcers.
C: Lepra - Unlikely, as leprosy does not typically present with painless inguinal lymph nodes and the specific ulcer characteristics described.
D: Trophic ulcer - Unlikely
Allergy to penicillin is an example of:
- A. Type I hypersensitivity reaction
- B. Type II hypersensitivity reaction
- C. Type III hypersensitivity reaction
- D. Type IV hypersensitivity reaction
Correct Answer: A
Rationale: Step-by-step rationale for choice A being correct:
1. Penicillin allergy involves IgE antibodies binding to penicillin.
2. This triggers mast cell degranulation, releasing histamine.
3. Histamine causes allergic symptoms like rash, swelling.
4. This immune response characterizes Type I hypersensitivity reactions.
Summary of other choices:
B: Type II reactions involve antibody-mediated cell destruction, not seen in penicillin allergy.
C: Type III reactions involve immune complex deposition, not typical in penicillin allergy.
D: Type IV reactions are delayed hypersensitivity reactions, not immediate like penicillin allergy.
Which bacteria is commonly associated with foodborne illnesses?
- A. Streptococcus pneumoniae
- B. Campylobacter jejuni
- C. Mycobacterium tuberculosis
- D. Haemophilus influenzae
Correct Answer: B
Rationale: The correct answer is B: Campylobacter jejuni. This bacteria is commonly associated with foodborne illnesses due to its presence in undercooked poultry and unpasteurized milk. Campylobacteriosis is a leading cause of bacterial gastroenteritis. Streptococcus pneumoniae (A) causes pneumonia, not foodborne illnesses. Mycobacterium tuberculosis (C) causes tuberculosis, not foodborne illnesses. Haemophilus influenzae (D) can cause respiratory infections but is not commonly associated with foodborne illnesses.
The bacterium Yersinia pestis is responsible for causing what disease?
- A. Tonsillitis
- B. Leprosy
- C. Plague
- D. Rat fever
Correct Answer: C
Rationale: The correct answer is C: Plague. Yersinia pestis is the bacterium responsible for causing the bubonic, septicemic, and pneumonic plague. The bacterium is transmitted to humans through infected flea bites or handling infected animals. Tonsillitis (A) is commonly caused by streptococcal bacteria, leprosy (B) is caused by Mycobacterium leprae, and rat fever (D) is another term for leptospirosis, caused by Leptospira bacteria.