[Apr 28, 2026] Get New ABMM Practice Test Questions Answers [Q82-Q104]

Q82. A patient with a history of recurrent Clostridioides difficile infection (CDI) is being considered for fecal microbiota transplantation (FMT). Pre-FMT screening of the donor stool sample should include comprehensive testing to exclude potential transmission of enteric pathogens. Which of the following would be the MOST critical to rule out in the donor stool?

Q83. A patient with a history of inflammatory bowel disease is diagnosed with primary sclerosing cholangitis and undergoes liver transplantation. Post-transplant, they develop a bloodstream infection with a Gram-negative bacterium that is identified as Fusobacterium nucleatum. This organism’s role in the pathogenesis of colorectal cancer is primarily attributed to its ability to:

Q84. During an outbreak of norovirus gastroenteritis in a nursing home, environmental swabs are collected to identify the source of the infection. Which of the following methods would be MOST appropriate for detecting norovirus in these samples?

Q85. A clinical microbiology laboratory is validating a new point-of-care test for the rapid detection of influenza A and B viruses. To accurately determine the clinical sensitivity of the test, it should be compared to a gold standard method using:

Q86. A patient with a history of travel to South America presents with fever, lymphadenopathy, and hepatosplenomegaly. Peripheral blood smear reveals the presence of trypomastigotes. The MOST likely diagnosis is:

Q87. A microbiology laboratory is processing a throat swab for the detection of Group A Streptococcus. Culture on sheep blood agar reveals beta-hemolytic colonies. Which of the following tests can be used to presumptively identify Streptococcus pyogenes?

Q88. A microbiology laboratory receives a corneal scraping from a patient with keratitis. Microscopic examination with calcofluor white stain reveals the presence of septate hyphae and conidiophores with a foot cell and phialides. The MOST likely genus is:

Q89. A patient with a history of valvular heart disease undergoes a dental procedure and subsequently develops a bloodstream infection with Streptococcus mutans. This organism gains access to the bloodstream primarily due to:

Q90. Clavulanic acid is often combined with amoxicillin (e.g., Augmentin™) to overcome certain types of bacterial resistance. What is the primary mechanism by which clavulanic acid enhances amoxicillin’s activity?

Q91. For epidemiological tracking and outbreak investigations of Clostridioides difficile infection (CDI), which molecular typing method based on PCR amplification targeting repetitive elements within the pathogenicity locus (PaLoc) has historically been widely used and designated by specific nomenclature (e.g., NAP1/BI
/027)?

Q92. A clinical trial is evaluating the efficacy of a new antifungal agent against invasive aspergillosis. Serum galactomannan levels are being used as a biomarker to monitor the infection. A decrease in galactomannan levels during treatment would indicate:

Q93. A traveler returning from Southeast Asia presents with fever, headache, and a maculopapular rash that started on the trunk and spread to the extremities, including the palms and soles. Serological testing is positive for Orientia tsutsugamushi. The vector responsible for transmitting this organism is a:

Q94. Which of the following bacterial genera inherently possesses D-alanyl-D-lactate peptide subunits in its peptidoglycan precursors, conferring natural, high-level resistance to vancomycin?

Q95. A patient with HIV infection and a CD4+ T-cell count of 30 cells/µL develops progressive multifocal leukoencephalopathy (PML). The causative agent of PML is:

Q96. A clinical laboratory manager is implementing a new automated blood culture system. Which aspect is LEAST likely to be part of the initial verification/validation process before clinical use?

Q97. A clinical microbiology laboratory is using a nucleic acid amplification test (NAAT) to detect Mycobacterium tuberculosis directly from sputum. A positive result indicates:

Q98. Which of the following organisms is an obligate intracellular bacterium transmitted by arthropod vectors and is a common cause of Rocky Mountain Spotted Fever?

Q99. A patient with a history of travel to Southeast Asia presents with fever, severe headache, and altered mental status. CSF analysis reveals lymphocytic pleocytosis and elevated protein, but routine bacterial and viral cultures are negative. Serological testing of CSF is positive for IgM antibodies against Japanese encephalitis virus. The MOST likely mode of transmission for this infection is:

Q100. A microbiology laboratory receives a sample of cerebrospinal fluid from a patient with suspected bacterial meningitis. The Gram stain shows Gram-positive diplococci. Culture on blood agar shows alpha-hemolytic colonies that are bile soluble and optochin-sensitive. The MOST likely organism is:

Q101. A patient undergoing chemotherapy for leukemia develops a severe pneumonia. Bronchoalveolar lavage fluid is examined, revealing numerous cysts containing crescent-shaped structures upon silver staining. The patient’s CD4+ T-cell count is significantly low. The MOST likely diagnosis is infection with:

Q102. A clinical microbiology laboratory is implementing a new real-time PCR assay for the direct detection of Chlamydia trachomatis in urine samples. To ensure the accuracy of negative results, it is essential to include:

Q103. A patient with recent abdominal surgery develops a fever, abdominal pain, and a wound infection. Gram stain of the wound exudate reveals a mixture of Gram-negative rods and Gram-positivebacilli. Anaerobic culture yields a foul-smelling, Gram-negative rod that is bile-esculin positive. The MOST likely organism is:

Q104. A patient develops a severe diarrheal illness after consuming raw oysters. Stool cultures grow a Gram- negative, comma-shaped bacterium that is oxidase-positive and grows on thiosulfate-citrate-bile salts-sucrose (TCBS) agar, producing green colonies. The MOST likely virulence factor contributing to the watery diarrhea is: