Question 1

Which of the following best describes a nosocomial infection?

Accepted Answer

A local or systemic infection acquired at a healthcare facility.

Question 2

A clinical microbiology laboratory is classified as BSL-3. Which of the following practices is most likely required in this setting?

Accepted Answer

Use of a biosafety cabinet and protective suits to prevent aerosol transmission.

Question 3

Which of the following is a major risk factor for healthcare-associated infections (HAIs)?

Accepted Answer

Use of anti-inflammatory drugs, which lowers resistance to infection.

Question 4

A blood culture is ordered for a patient suspected of septicemia. What is the standard procedure for collecting and culturing the blood sample?

Accepted Answer

Draw 10–20 mL of blood and culture in two bottles: one aerobic and one anaerobic.

Question 5

Which medium would be most appropriate for isolating methicillin-resistant Staphylococcus aureus (MRSA) from a wound sample?

Accepted Answer

Chromogenic agar, which is both selective and differential for MRSA.

Question 6

The minimum inhibitory concentration (MIC) is determined by:

Accepted Answer

Measuring the lowest concentration of antibiotic that inhibits visible growth of a test organism.

Question 7

Which of the following best explains why $$eta-$$lactam antibiotics are selectively toxic to bacteria?

Accepted Answer

They target cell wall synthesis, which is unique to bacteria.

Question 8

A patient’s infection is suspected to be caused by Neisseria gonorrhoeae. Which laboratory method would provide the most rapid presumptive identification?

Accepted Answer

Observation of gram-negative diplococci in neutrophils from a tissue sample.

Question 9

Which of the following statements about ELISA (enzyme-linked immunosorbent assay) is correct?

Accepted Answer

ELISA uses enzyme-conjugated antibodies to detect specific antigens or antibodies.

Question 10

Which of the following is a mechanism by which bacteria can acquire resistance to antibiotics?

Accepted Answer

Inactivating the antibiotic with enzymes.

Question 11

A laboratory uses quantitative real-time PCR (qPCR) to detect a pathogen. What is the main advantage of this technique?

Accepted Answer

It provides almost immediate results by detecting amplified gene products in real time.

Question 12

Which of the following antibiotics acts by interfering with bacterial DNA gyrase?

Accepted Answer

Ciprofloxacin

Question 13

Which of the following best describes the principle of agglutination tests?

Accepted Answer

Visible clumping of particulate antigen when mixed with specific antibodies.

Question 14

Why are bacterial ribosomes a good target for antibiotics that inhibit protein synthesis?

Accepted Answer

Bacterial ribosomes are structurally different from eukaryotic ribosomes, allowing selective toxicity.

Question 15

Which of the following is NOT a reason why a microorganism might be naturally resistant to an antibiotic?

Accepted Answer

The organism lacks a cell wall, making it susceptible to $$eta-$$lactam antibiotics.

Question 16

A patient is suspected of having a viral infection. Which diagnostic method would most rapidly confirm the presence of viral genetic material?

Accepted Answer

Reverse transcriptase PCR (RT-PCR) to detect viral RNA.

Question 17

Which of the following best describes the use of monoclonal antibodies in clinical diagnostics?

Accepted Answer

They are produced by fusing a single B cell clone with a cancer cell to create an immortalized cell line.

Question 18

Which of the following is a characteristic of broad-spectrum antibiotics?

Accepted Answer

They are effective against both gram-positive and gram-negative bacteria.

Question 19

A patient with a wound infection is found to have MRSA. Which of the following best explains why MRSA is a clinical concern?

Accepted Answer

MRSA is resistant to methicillin and often other antibiotics, making infections difficult to treat.

Question 20

Which of the following is the best example of selective media?

Accepted Answer

A medium that allows only certain organisms to grow while inhibiting others.

Clinical Microbiology: Laboratory Safety, Diagnosis, and Antimicrobial Therapy

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