ATI RN
free microbiology test bank questions pdf Questions
Question 1 of 5
Microscopy of a smear obtained from a patient with acute purulent periostitis revealed gram-positive bacteria arranged in clusters resembling bunch of grapes. What microorganisms is this morphology typical for?
Correct Answer: A
Rationale:
Rationale:
Staphylococci are gram-positive bacteria that typically arrange in clusters resembling a bunch of grapes. This characteristic morphology is specific to staphylococci due to their division pattern. Sarcina, Tetracocci, and Candida fungi do not exhibit this clustering pattern. Staphylococci are commonly associated with purulent infections, making them the most likely microorganisms in this scenario.
Question 2 of 5
Which bacteria produce exotoxins that affect the nervous system?
Correct Answer: A
Rationale: The correct answer is A: Clostridium botulinum and Clostridium tetani. Both bacteria produce exotoxins that affect the nervous system. Clostridium botulinum produces botulinum toxin, causing botulism, leading to muscle paralysis. Clostridium tetani produces tetanospasmin, causing tetanus, leading to muscle stiffness and spasms.
Choice B (Escherichia coli and Salmonella) are known for causing gastrointestinal infections, not specifically affecting the nervous system.
Choice C (Bacillus anthracis and Listeria monocytogenes) produce toxins that primarily affect other body systems, not the nervous system.
Choice D (Pseudomonas aeruginosa and Staphylococcus aureus) are associated with skin and respiratory infections, not neurological effects.
Question 3 of 5
The human pinworm Enterobius vermicularis lives in the __________ of humans.
Correct Answer: D
Rationale: The correct answer is D: rectum. Pinworms typically inhabit the rectum area in humans, where they lay their eggs. This is because the female pinworm migrates to the rectum at night to deposit her eggs near the anus. Other choices are incorrect because pinworms do not reside in the duodenum (
A), ileum (
B), or transverse colon (
C) as their primary location is in the lower gastrointestinal tract near the anus.
Question 4 of 5
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?
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.
Question 5 of 5
Which bacterium is responsible for causing pneumonia?
Correct Answer: A
Rationale: The correct answer is A: Streptococcus pneumoniae. This bacterium is the most common cause of bacterial pneumonia in adults. It is a leading cause of community-acquired pneumonia. Streptococcus pneumoniae is known for its ability to infect the respiratory tract and cause inflammation in the lungs leading to pneumonia. Mycobacterium tuberculosis causes tuberculosis, not pneumonia. Escherichia coli is associated with urinary tract infections and gastrointestinal illnesses, not pneumonia. Clostridium botulinum causes botulism, a severe form of food poisoning, but not pneumonia.
Therefore, the correct choice is Streptococcus pneumoniae as it is specifically known for causing pneumonia.