Nokea
For family Rhabdoviridae is true that:
- A. They are enveloped viruses
- B. They cause plague
- C. They have spherical shape
- D. They infect only humans
Correct Answer: A
Rationale: The correct answer is A: They are enveloped viruses. Rhabdoviridae family consists of enveloped viruses, which means they have a lipid envelope surrounding their protein coat. This envelope helps the virus in infecting host cells and evading the immune system. The other choices are incorrect because B: They cause plague is not true as Rhabdoviridae family typically causes diseases like rabies in mammals. C: They have spherical shape is incorrect as rhabdoviruses have a bullet-shaped structure. D: They infect only humans is also incorrect as Rhabdoviridae viruses can infect a wide range of hosts beyond just humans.
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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.
Erysipelas is a bacterial infection characterised by well-defined areas of bright-red, inflamed and rough or leathery skin. Which one is the causative agent:
- A. Pseudomonas aeruginosa
- B. Staphylococcus aureus
- C. Streptococcus pyogenes
- D. Candida albicans
Correct Answer: C
Rationale: Step-by-step rationale for Choice C (Streptococcus pyogenes) being the correct answer:
1. Erysipelas is a skin infection characterized by well-defined red, inflamed skin areas.
2. Streptococcus pyogenes is a common causative agent of erysipelas.
3. This bacterium produces enzymes that break down skin proteins, leading to the characteristic symptoms of erysipelas.
4. Streptococcus pyogenes is known for causing skin infections, including erysipelas.
Summary of why the other choices are incorrect:
A. Pseudomonas aeruginosa: Typically causes opportunistic infections, but not commonly associated with erysipelas.
B. Staphylococcus aureus: Can cause skin infections, but not typically associated with erysipelas.
D. Candida albicans: Fungal infection, not a bacterium, and not known to cause erysipelas.
A patient with a long history of chronic gastritis undergoes a gastroscopy, which detects an ulcer in the duodenum area. Microscopic examination of the tissue biopsy developed Gram-negative curved bacteria and the rapid urease activity test of the biopsy material was highly positive. The most likely cause of the disease is:
- A. Vibrio cholerae
- B. Campylobacter fetus
- C. Acinetobacter baumannii
- D. Helicobacter pylori
Correct Answer: D
Rationale: The correct answer is D: Helicobacter pylori. Helicobacter pylori is a known bacterium associated with causing duodenal ulcers. The presence of Gram-negative curved bacteria in the biopsy along with a highly positive rapid urease test is characteristic of H. pylori infection. Vibrio cholerae causes cholera, not duodenal ulcers. Campylobacter fetus is associated with gastroenteritis, not duodenal ulcers. Acinetobacter baumannii is a nosocomial pathogen, not typically associated with duodenal ulcers. In summary, the unique combination of findings in this case points towards H. pylori as the most likely cause of the disease.
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.
There are several cases of children from boarding school suffering from sore throat. Microscopy of tonsil smears stained according Neisser method has revealed thin yellow bacilli with dark brown grains on their ends placed in the shape of Roman numeral five. What infection can be suspected in this case?
- A. Diphtheria
- B. Scarlet fever
- C. Listeriosis
- D. Tonsilitis
Correct Answer: A
Rationale: Rationale for Correct Answer A (Diphtheria):
1. Thin yellow bacilli with dark brown grains on ends suggest Corynebacterium diphtheriae, characteristic of diphtheria.
2. Roman numeral five shape is typical of diphtheria bacilli.
3. Diphtheria causes sore throat and can spread in boarding schools.
4. Neisser staining method is used for diphtheria bacilli.
Summary of Incorrect Choices:
B: Scarlet fever is caused by Streptococcus pyogenes and presents with rash, not yellow bacilli.
C: Listeriosis is caused by Listeria monocytogenes, not consistent with the described findings.
D: Tonsillitis can be caused by various bacteria or viruses, but the specific characteristics described do not match.