Nokea
Which is the most prominent immunoglobulin class present in external secretions
- A. IgG
- B. IgM
- C. IgA
- D. IgE
Correct Answer: C
Rationale: The correct answer is C: IgA. IgA is the most prominent immunoglobulin class present in external secretions like saliva, tears, and mucus. It plays a crucial role in mucosal immunity by preventing pathogens from entering the body. IgG is mainly found in the blood and tissues, IgM is the first antibody produced in response to an infection, and IgE is involved in allergic reactions. IgA's presence in external secretions helps protect the body from infections at mucosal surfaces, making it the correct choice in this context.
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Urine examination of a patient with acute cystitis revealed leukocytes and a lot of gram-negative bacilli. Inoculation resulted in growth of colonies of mucous nature that formed green soluble pigment. What microorganism is the most probable cause of the disease?
- A. Pseudomonas aeruginosa
- B. Klebsiella pneumoniae
- C. Escherihia coli
- D. Salmonella enteritidis
Correct Answer: C
Rationale: Rationale:
1. Presence of gram-negative bacilli suggests Enterobacteriaceae family, which includes E. coli.
2. Green soluble pigment indicates pyocyanin production, characteristic of E. coli.
3. E. coli is the most common cause of acute cystitis due to its ability to colonize the urinary tract.
Summary:
A: Pseudomonas aeruginosa is not typically associated with acute cystitis and does not produce mucous colonies.
B: Klebsiella pneumoniae may cause UTIs, but does not produce green pigment and is less common than E. coli.
D: Salmonella enteritidis is associated with gastrointestinal infections, not cystitis.
Which of the following bacteria is known for producing a biofilm on medical devices?
- A. Clostridium tetani
- B. Pseudomonas aeruginosa
- C. Salmonella enterica
- D. Staphylococcus aureus
Correct Answer: B
Rationale: The correct answer is B: Pseudomonas aeruginosa. This bacterium is known for producing biofilms on medical devices due to its ability to adhere and form a slimy layer that protects it from antibiotics and the host immune system. Pseudomonas aeruginosa is commonly associated with healthcare-associated infections.
Clostridium tetani (A) causes tetanus, not known for biofilm production on medical devices. Salmonella enterica (C) causes foodborne illnesses, not typically associated with medical device biofilms. Staphylococcus aureus (D) is a common pathogen in healthcare settings but is not specifically known for biofilm production on medical devices.
Which form of human plague is present with high fever and large lymphadenopathies (buboes). The case fatality in untreated cases may reach 60%.
- A. Bubonic plague
- B. Pneumonic plague
- C. Gastrointestinal plague
- D. Septicemic plague
Correct Answer: A
Rationale: The correct answer is A: Bubonic plague. Bubonic plague is characterized by high fever and large swollen lymph nodes (buboes). The case fatality rate in untreated cases can reach 60%. This form of plague is typically transmitted through the bite of an infected flea.
B: Pneumonic plague presents with respiratory symptoms and is transmitted through respiratory droplets.
C: Gastrointestinal plague is not a recognized form of plague.
D: Septicemic plague is a severe form of plague where the bacteria multiply in the bloodstream. It may not always present with buboes.
When examining a patient with a suspicion of food toxicoinfection, a doctor on duty has detected symptoms characteristic of botulism. The patient named the meals he had eaten the day before. What is the most probable cause of infection?
- A. Homemade canned meat
- B. Custard pastry from private bakery
- C. Sour cream from local dairy factory
- D. Strawberries from suburban vegetable garden
Correct Answer: A
Rationale: The correct answer is A: Homemade canned meat. Botulism is often caused by consuming improperly canned or preserved foods, particularly meats. The spores of the Clostridium botulinum bacteria can grow in anaerobic conditions, such as those found in improperly canned foods, leading to the production of the botulinum toxin. The symptoms of botulism align with those characteristic of the patient's condition.
Explanation of why the other choices are incorrect:
B: Custard pastry from private bakery - Unlikely to be the cause of botulism as this type of food is not typically associated with the growth of Clostridium botulinum.
C: Sour cream from local dairy factory - While dairy products can sometimes be sources of foodborne illness, botulism is not commonly associated with sour cream.
D: Strawberries from suburban vegetable garden - Botulism is not typically transmitted through fresh fruits or vegetables, making this an unlikely source of infection.
Which of the following pathogens can cause meningitis?
- A. Staph. aureus
- B. Strep. pyogenes
- C. Strep. pneumoniae
- D. None of the above
Correct Answer: C
Rationale: Rationale for choice C (Strep. pneumoniae):
1. Strep. pneumoniae is a common cause of bacterial meningitis.
2. It is a leading pathogen responsible for meningitis in adults and children.
3. It can invade the bloodstream and reach the meninges, causing inflammation.
4. Treatment guidelines often include antibiotics effective against Strep. pneumoniae.
Summary of why other choices are incorrect:
A. Staph. aureus is not a common cause of meningitis.
B. Strep. pyogenes typically causes streptococcal infections but not meningitis.
D. "None of the above" is incorrect as Strep. pneumoniae can cause meningitis.