ATI RN
microbiology chapter 1 test bank Questions
Question 1 of 5
Microscopy of a wound smear revealed Gram-positive rods with terminal spores resembling drumsticks. What microorganism is most likely responsible?
Correct Answer: A
Rationale: The correct answer is A: Clostridium tetani. The presence of Gram-positive rods with terminal spores resembling drumsticks indicates Clostridium tetani, the causative agent of tetanus. This bacterium forms spores at one end, giving it a drumstick appearance under the microscope. Clostridium perfringens (B) and Clostridium botulinum (D) do not have terminal spores. Bacillus anthracis (C) forms spores but typically appears as a square-ended or bamboo stick shape. Therefore, based on the microscopy findings, Clostridium tetani is the most likely microorganism responsible for the wound infection.
Question 2 of 5
In the sixteenth century, a father-and-son team, by the name of __________, produced a compound microscope consisting of a simple tube with lenses at each end.
Correct Answer: C
Rationale: The correct answer is C: Janssen. In the 16th century, Hans and Zacharias Janssen were a father-and-son team from the Netherlands who are credited with inventing the compound microscope. They constructed a simple tube with lenses at each end, which allowed for magnification of small objects. Their invention significantly contributed to the development of microscopy. Van Leeuwenhoek is known for his contributions to microscopy but did not invent the compound microscope. Semmelweis is known for his work in handwashing and preventing infection. Hooke made significant contributions to microscopy but did not invent the compound microscope.
Question 3 of 5
A patient with foul-smelling diarrhea had a stool sample showing large ciliated protozoa with a kidney-shaped macronucleus. What is the diagnosis?
Correct Answer: A
Rationale: The correct answer is A: Balantidiasis. The large ciliated protozoa with a kidney-shaped macronucleus described in the stool sample is consistent with Balantidium coli, the causative agent of balantidiasis. Balantidium coli is the only ciliated protozoan parasite that infects humans and presents with these specific characteristics. Giardiasis (B) is caused by Giardia intestinalis, which is flagellated, not ciliated. Amoebiasis (C) is caused by Entamoeba histolytica, which has an amoeboid shape, not ciliated. Trichomoniasis (D) is caused by Trichomonas vaginalis, which is a flagellated protozoan and does not have a kidney-shaped macronucleus. Hence, the correct diagnosis in this case is Balantidiasis.
Question 4 of 5
A patient with pneumonia had a sputum smear stained by the Gram method revealing Gram-positive cocci in pairs. What is the most likely causative agent?
Correct Answer: A
Rationale: The correct answer is A: Streptococcus pneumoniae. The presence of Gram-positive cocci in pairs indicates a bacterial morphology consistent with Streptococcus pneumoniae, a common cause of pneumonia. This bacterium is known to appear in pairs or short chains on Gram stain. Staphylococcus aureus (B) typically presents as clusters of Gram-positive cocci, Neisseria meningitidis (C) is a Gram-negative diplococcus, and Klebsiella pneumoniae (D) is a Gram-negative rod, making them less likely causative agents in this scenario.
Question 5 of 5
A child with an enlarged, painful lymph node had Gram-negative rods with a safety pin appearance. What is the causative agent?
Correct Answer: A
Rationale: The correct answer is A: Yersinia pestis. Y. pestis causes bubonic plague, characterized by enlarged, painful lymph nodes called buboes. The Gram-negative rods with a safety pin appearance are seen on Gram stain of Y. pestis. The other choices are incorrect because Francisella tularensis causes tularemia, not lymphadenitis with safety pin appearance. Brucella abortus causes brucellosis, which typically does not present with lymphadenitis. Clostridium botulinum causes botulism, which is not associated with lymphadenitis or safety pin appearance.