100% Free American Society for Microbiology ABMM Practice Test Questions and Answers 2026

Start Learning with the Latest and Real 100% Free American Society for Microbiology ABMM Exam Questions

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Total 205 Questions | Updated On: May 22, 2026

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Question 1

During the investigation of a foodborne illness outbreak linked to raw sprouts, several bacterial isolates are obtained from patient stool samples and the implicated food source. Which of the following molecular methods would be MOST useful for establishing a definitive link between the clinical isolates and the food isolate?

A : Gram staining and biochemical profiling

B : Serotyping based on O and H antigens

C : Pulsed-field gel electrophoresis (PFGE)

D : Antimicrobial susceptibility testing

Answer: C

Question 2

A microbiology laboratory is processing a stool sample for ova and parasites. A large (approximately 100 µm), thick-shelled, oval egg with a flattened side is observed. This egg MOST likely belongs to:

A : Ascaris lumbricoides

B : Enterobius vermicularis

C : Taenia species

D : Trichuris trichiura

Answer: A

Question 3

A clinical microbiology laboratory is investigating a cluster of Clostridium difficile infections in a hospital. Which of the following methods is MOST appropriate for determining if the isolates from different patients are related?

A : Gram staining and morphology

B : Antimicrobial susceptibility testing

C : Enzyme immunoassay for C. difficile toxins

D : Molecular typing (e.g., PCR ribotyping)

Answer: D

Question 4

The human virome, the collection of viruses that reside in and on the human body, is increasinglyrecognized for its role in health and disease. Which of the following statements regarding the human virome is MOST accurate?

A : The human virome is primarily composed of pathogenic viruses that cause acute infections.

B : The composition of the human virome is relatively stable over time and is not influenced by environmental factors.

C : Bacteriophages, viruses that infect bacteria, are a significant component of the human gut virome.

D : The human virome is largely independent of the host's immune status.

Answer: C

Question 5

Metagenomic analysis of a bronchoalveolar lavage (BAL) sample from a patient with severe pneumonia reveals a complex microbial community with a high abundance of both bacterial and fungal sequences. This approach is particularly useful in identifying:

A : The specific antibiotic susceptibility profile of the predominant bacterial pathogen.

B : The presence of fastidious or unculturable pathogens that may be missed by traditional methods.

C : The relative proportions of different immune cell populations in the BAL fluid.

D : The presence of specific virulence factors expressed by the identified pathogens.

Answer: B

Page: 1 / 41

Total 205 Questions | Updated On: May 22, 2026

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