Real ABMM Exam Questions are the Best Preparation Material [Q93-Q115]

Q93. A research laboratory is investigating the mechanism of action of a novel antiviral compound that inhibits the replication of a specific RNA virus. They find that the compound binds directly to the viral RNA-dependent RNA polymerase, preventing its elongation activity. This mechanism is most similar to that of:

Q94. A Gram stain of anaerobic growth from a peritoneal fluid abscess reveals pleomorphic, pale-staining Gram- negative rods. The isolate grows on Bacteroides Bile Esculin (BBE) agar, hydrolyzing esculin (producing black colonies), and is resistant to kanamycin (1000 µg), vancomycin (5 µg), and colistin (10 µg) disks. Which organism group is most likely?

Q95. A patient with a history of intravenous drug use develops a bloodstream infection with Staphylococcus aureus. Antimicrobial susceptibility testing reveals resistance to methicillin. The mechanism of methicillin resistance in Staphylococcus aureus is primarily mediated by:

Q96. A research laboratory is investigating the mechanisms of antiviral drug resistance. They are studying a herpes simplex virus strain that has developed resistance to acyclovir. The MOST common mechanism of acyclovir resistance in HSV involves mutations in the gene encoding:

Q97. A clinical microbiology laboratory is implementing whole-genome sequencing (WGS) for enhanced surveillance of Listeria monocytogenes isolates associated with foodborne outbreaks. WGS provides several advantages over traditional subtyping methods like pulsed-field gel electrophoresis (PFGE). Which of the following is the MOST significant advantage of WGS in this context?

Q98. A patient with a history of travel to a rural area develops a febrile illness with myalgias and thrombocytopenia. Laboratory testing reveals the presence of morulae within circulating leukocytes. The MOST likely diagnosis is:

Q99. An acid-fast bacillus isolate recovered from a respiratory specimen after 3 weeks of incubation on Löwenstein- Jensen medium is initially non-pigmented when grown in the dark. After exposure to light for several hours, the colonies develop a distinct yellow-orange pigment. This organism is classified as a:

Q100. A microbiology laboratory is performing antimicrobial susceptibility testing using the Kirby-Bauer disk diffusion method. A bacterial isolate shows no zone of inhibition around a specific antibiotic disk. This result could be due to:

Q101. According to the current CDC-recommended laboratory algorithm for diagnosing HIV infection in adults and children aged >18 months, what is the recommended initial screening test?

Q102. Microscopic examination of a Calcofluor white stained sputum sample from an immunocompromised patient with suspected invasive pulmonary infection reveals septate hyphae that branch dichotomously at acute (approximately 45°) angles. Conidial structures are observed, showing conidiophores arising from a specialized foot cell, terminating in a flask-shaped vesicle that bears phialides only on the upper two-thirds (uniseriate arrangement). Chains of small, round conidia are produced. This morphology is most characteristic of:

Q103. Which serological marker pattern is most consistent with chronic Hepatitis B virus infection with high infectivity?

Q104. A clinical microbiology laboratory is investigating a potential outbreak of a highly contagious respiratory virus. To rapidly screen a large number of nasopharyngeal swabs, the MOST appropriate initial diagnostic test would be:

Q105. During a primary infection with Epstein-Barr virus (EBV), the virus establishes latency in B lymphocytes.
The transition from lytic to latent infection is tightly regulated by viral gene expression. Which of the following viral proteins is crucial for the establishment and maintenance of EBV latency and is a key target in EBV-associated lymphomas?

Q106. Besides traditional Giemsa-stained thick and thin blood smears, which diagnostic approach is commonly employed as a rapid diagnostic test (RDT) for malaria detection, particularly in resource-limited settings?

Q107. A clinical microbiology laboratory is investigating a potential outbreak of Legionella pneumophila associated with a hospital’s water system. The MOST appropriate environmental samples to collect for culture and comparison to clinical isolates would be:

Q108. 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?

Q109. A research laboratory is investigating the mechanisms of antigenic variation in Trypanosoma brucei, the causative agent of African trypanosomiasis. The parasite evades the host immune response by periodically changing its surface coat protein. This process primarily involves:

Q110. 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:

Q111. A clinical microbiology laboratory is using PCR to detect the presence of the mecA gene in Staphylococcus aureus isolates. The mecA gene encodes for:

Q112. A patient with a history of chronic lung disease develops a severe pneumonia. Bronchoalveolar lavage fluid reveals the presence of numerous cysts containing multiple nuclei, which stain positively with silver stains but poorly with Gram stain. The patient’s CD4+ T-cell count is within the normal range. The MOST likely causative organism and the preferred treatment are:

Q113. A patient with a history of travel to a tropical region presents with cyclical fevers and chills.Peripheral blood smear reveals the presence of merozoites and schizonts within erythrocytes. The absence of crescent-shaped gametocytes makes Plasmodium falciparum less likely. The MOST probable species is:

Q114. A serum sample from an asymptomatic patient screened for syphilis yields a reactive Rapid Plasma Reagin (RPR) test result with a titer of 1:16, but a non-reactive Treponema pallidum particle agglutination (TP-PA) test. What is the most likely interpretation of these findings?

Q115. An immunocompromised patient develops a disseminated fungal infection. Blood cultures are consistently negative. However, a serum beta-D-glucan assay is markedly elevated. Tissue biopsy reveals the presence of hyaline, septate hyphae with dichotomous branching. The MOST likely causative organism is: