American Society of Microbiology ASM-ABMM Online Practice Questions and Exam Preparation

American Society of Microbiology ASM-ABMM Online Questions & Answers

• Question 1:

  A patient develops severe, watery diarrhea shortly after starting a course of clindamycin. Stool testing using a cytotoxicity assay is positive. This result is most consistent with infection by which organism?

  A. Campylobacter jejuni
  B. Clostridioides difficile
  C. Giardia lamblia
  D. Norovirus
  B. Clostridioides difficile

• Question 2:

  A patient with a history of neutropenia following chemotherapy develops a rapidly progressive pneumonia. Bronchoalveolar lavage fluid reveals septate hyphae with acute angle (45-degree) branching. The MOST likely diagnosis is invasive pulmonary aspergillosis caused by:

  A. Aspergillus fumigatus
  B. Mucor species
  C. Rhizopus species
  D. Fusarium species
  A. Aspergillus fumigatus

• Question 3:

  A Gram-positive rod is isolated from the blood culture of a neonate with sepsis. The organism exhibits weak beta-hemolysis on sheep blood agar, is catalase-positive, hydrolyzes esculin in the presence of bile, and demonstrates characteristic "tumbling" motility in a wet mount prepared from a broth culture incubated at 25A. Corynebacterium jeikeium
  B. Bacillus anthracis
  C. Listeria monocytogenes
  D. Erysipelothrix rhusiopathiae

  C. Listeria monocytogenes

• Question 4:

  A patient with a history of chronic sinusitis develops a severe invasive fungal infection involving the nasal sinuses and extending into the orbit. Tissue biopsy reveals broad, aseptate hyphae with irregular branching. The patient is diabetic and acidotic. The MOST likely causative organism belongs to the genus:

  A. Aspergillus
  B. Fusarium
  C. Mucor or Rhizopus
  D. Scedosporium
  C. Mucor or Rhizopus

• Question 5:

  A research laboratory is investigating the mechanisms of viral latency in herpes simplex virus type 1 (HSV-1). During latency in sensory neurons, the viral genome exists as a circular episome. Whichof the following viral gene products is thought to play a crucial role in maintaining this latent state and preventing viral gene expression?

  A. Immediate-early (IE) proteins such as ICP4 and ICP27.
  B. Early (E) proteins such as thymidine kinase and DNA polymerase.
  C. Late (L) proteins such as structural glycoproteins.
  D. Latency-associated transcripts (LATs).
  D. Latency-associated transcripts (LATs).

• Question 6:

  A patient with a history of intravenous drug use develops a bloodstream infection with Enterococcus faecalis. Antimicrobial susceptibility testing reveals resistance to vancomycin. The MOST likely mechanism of vancomycin resistance in Enterococcus involves:

  A. Production of enzymes that inactivate vancomycin.
  B. Modification of the peptidoglycan precursor, reducing vancomycin binding.
  C. Increased expression of efflux pumps that actively transport vancomycin out of the cell.
  D. Alteration of the ribosomal target site, preventing vancomycin binding to the ribosome.
  B. Modification of the peptidoglycan precursor, reducing vancomycin binding.

• Question 7:

  Transmissible spongiform encephalopathies (TSEs), such as Creutzfeldt-Jakob disease (CJD) in humans and Bovine Spongiform Encephalopathy (BSE) in cattle, are caused by infectious agents composed primarily of:

  A. Viroids (small, circular RNA molecules)
  B. Defective viral particles requiring a helper virus
  C. Aberrantly folded host-encoded prion proteins (PrPandlt;sup>Scandlt;/sup>)
  D. Slow-growing bacteria lacking a cell wall
  C. Aberrantly folded host-encoded prion proteins (PrPandlt;sup>Scandlt;/sup>)

• Question 8:

  A clinical microbiology laboratory is using flow cytometry to analyze lymphocyte subsets in a patient with suspected immunodeficiency. Which of the following cell surface markers is typically used to identify helper T cells?

  A. CD8
  B. CD4
  C. CD19
  D. CD56
  B. CD4

• Question 9:

  A researcher is studying the genetic relatedness of different isolates of Mycobacterium tuberculosis. Which of the following molecular typing methods provides the highest discriminatory power for distinguishing between closely related strains?

  A. Restriction fragment length polymorphism (RFLP) analysis
  B. Pulsed-field gel electrophoresis (PFGE)
  C. Spoligotyping
  D. Whole-genome sequencing (WGS)
  D. Whole-genome sequencing (WGS)

• Question 10:

  During the processing of stool specimens for ova and parasite examination, the formalin- ethyl acetate concentration procedure primarily serves to:

  A. Preserve parasite morphology and kill bacteria
  B. Separate parasites from fecal debris and concentrate them
  C. Selectively culture protozoan trophozoites
  D. Stain parasite nuclei for easier identification
  B. Separate parasites from fecal debris and concentrate them