Deck 28: Clinical Microbiology and Immunology

Question 1

Widespread antimicrobial drug resistance is usually passed by

A) heterologous gene expression.
B) reverse transcription.
C) horizontal gene transfer.
D) gene splicing.

Answer 1

C

Question 2

Latex bead agglutination tests are

A) rapid and reliable tests used for the detection of certain bacteria as well as certain serum antibodies.
B) inferior tests used in developing countries not having facilities for more reliable assays.
C) an integral part of the EIA test procedure.
D) too expensive for routine use.

Answer 2

A

Question 3

MacConkey agar and eosin-methylene blue (EMB) agar are ________ media.

A) selective but not differential
B) differential but not selective
C) both selective and differential
D) neither selective nor differential

Answer 3

C

Question 4

Which of the following is a mechanism of aminoglycosides?

A) inhibition of cell wall biosynthesis
B) prevention of peptidoglycan crosslinking
C) inhibition of DNA replication
D) targeting the 30S ribosomal subunit

Question 5

Modified Thayer-Martin (MTM) agar

A) incorporates antibiotics into the medium.
B) enhances the growth of normal flora.
C) prevents the growth of Neisseria gonorrhoeae, but promotes the growth of Neisseria meningitidis.
D) prevents the growth of Neisseria meningitides, but promotes the growth of Neisseria gonorrhoeae.

Question 6

One advantage of the fluorescent antibodies that permits disease diagnosis long before primary isolation techniques yield results is that

A) cross-reactions do not occur.
B) few controls are required.
C) nonspecific staining does not occur.
D) it may be applied directly to tissue.

Question 7

________ infections are among the most common nosocomial infections.

A) Lymphatic
B) Reproductive tract
C) Skin
D) Respiratory tract

Question 8

Some antibiotics inhibit protein synthesis by disruption of translation through interactions with the

A) ribosome.
B) protein.
C) DNA.
D) chromosome.

Question 9

Which type of medium allows a variety of microbes to grow but often changes color in the right conditions, such as when fermentation causes a pH change?

A) selective but not differential
B) differential but not selective
C) both selective and differential
D) neither selective nor differential

Question 10

The component that enriches chocolate agar is

A) chocolate.
B) methyl brown indicator dye.
C) heat-lysed blood cells.
D) None of the answers are correct.

Question 11

Laboratories that work with extremely low risk pathogens are classified as

A) BSL-1.
B) BSL-2.
C) BSL-3.
D) BSL-4.

Question 12

The oxygen-free gas commonly employed during anoxic incubation of a bacterial culture is a mixture of

A) nitrogen and carbon dioxide.
B) nitrogen and carbon monoxide.
C) nitrogen and argon.
D) nitrogen and hydrogen.

Question 13

The first antibiotic to be characterized was a

A) cephalosporin.
B) quinolone.
C) β-lactam.
D) macrolide.

Question 14

The blotting of proteins from polyacrylamide gels to nitrocellulose paper, and the subsequent identification by specific antibodies, is called a(n) ________ blot.

A) Western
B) Eastern
C) Southern
D) Northern

Question 15

Which of the following immunological tests would allow the specific identification of a microorganism directly in infected tissues?

A) fluorescent antibody (FA)
B) radioimmunoassay (RIA)
C) enzyme-linked immunosorbent assay (EIA)
D) agglutination

Question 16

EMB agar preferentially selects for the growth of ________ bacteria.

A) gram-positive
B) gram-negative
C) gram-variable
D) both gram-positive and gram-negative

Question 17

The disk-diffusion test is used for

A) assessing antimicrobial activity.
B) the identification of Escherichia coli.
C) the identification of viral plaques.
D) the detection of antigen.

Question 18

An Etest is a clinical tool used for the determination of

A) enteric presence.
B) Escherichia coli O157:H7 presence.
C) the minimum inhibitory concentration (MIC) value of an antimicrobial agent.
D) pathogenic enzyme activity.

Question 19

Which of the following must be accomplished FIRST in order to conduct RT-PCR?

A) Complementary DNA must be synthesized from double-stranded DNA.
B) Complementary DNA must be synthesized from RNA.
C) Complementary DNA must be synthesized from proteins.
D) Complementary DNA must be synthesized from single-stranded DNA.

Question 20

Which of the following would be useful for treating Candida?

A) an azole
B) a fusion inhibitor
C) a macrolide
D) a nucleoside reverse transcriptase inhibitor

Question 21

The tuberculin skin test looks to identify ________ specific to Mycobacterium tuberculosis.

A) antibodies
B) antigens
C) delayed hypersensitive (DTH) TH1 cells
D) delayed hypersensitive (DTH) TC cells

Question 22

Most drug-resistant bacteria isolated from patients contain a(n)

A) R plasmid.
B) T1 phage.
C) reverse transcriptase.
D) β-lactam.

Question 23

Two common or important bacterial pathogens found in the blood are

A) Pseudomonas aeruginosa and Escherichia coli.
B) Enterobacter and Proteus.
C) Shigella and Salmonella.
D) HIV and Escherichia coli.

Question 24

Compared with other precipitation tests, agglutination tests are

A) more sensitive.
B) less sensitive.
C) about equally sensitive.
D) highly variable in sensitivity, and thus the sensitivities cannot be compared.

Question 25

Which of the following prevents supercoiling of bacterial DNA?

A) macrolides
B) quinolones
C) penicillins
D) cephalosporins

Question 26

Which of the following is a novel antimicrobial target?

A) disruption of lipid biosynthesis
B) inhibition of protein synthesis
C) inhibition of cell wall biosynthesis
D) inhibition of peptidoglycan crosslinking

Question 27

In the United States, every clinical and research institution requires that workers be protected from ________, a pathogen that is contracted almost exclusively from handling patient specimens (rather than from known exposure or accidents).

A) anthrax
B) hepatitis B
C) drug-resistant mycobacteria
D) influenza

Question 28

A gram-negative, oxidase-positive diplococcus growing on chocolate agar likely belongs to the genus

A) Neisseria.
B) Escherichia.
C) Mycobacterium.
D) Pseudomonas.

Question 29

Blood agar is an example of amedium that supports the growth of many microbes. Medium that supports a wide variety of growth is called ________ medium.

A) selective
B) general-purpose
C) stable
D) halophilic

Question 30

The basis for blood typing is referred to as

A) neutralization.
B) hemagglutination.
C) immunodiffusion.
D) precipitation.

Question 31

Protein A, commonly used in immunoblots, is derived from

A) Staphylococcus.
B) Escherichia.
C) Bacillus.
D) Clostridium.

Question 32

Blood infections are most commonly caused by Enterococcus and ________, among many other genera.

A) Staphylococcus
B) Coryneform bacteria
C) Propionibacteria
D) Escherichia coli

Question 33

Eukaryotic intestinal parasites, such as Giardia, can be identified by observing stool samples for the presence of

A) cysts.
B) antibodies.
C) LPS.
D) blood.

Question 34

Which bacterium shows a characteristic metallic green sheen when grown on eosin-methylene blue (EMB) agar?

A) Escherichia coli
B) Salmonella enterica
C) Staphylococcus aureus
D) Streptococcus pyogenes

Question 35

A laboratory in which Ebola virus is studied would be classified as a BSL-________ laboratory.

A) 1
B) 2
C) 3
D) 4

Question 36

________ defines the lowest quantity of an antigen that can be detected in a serological test.

A) Specificity
B) Antigenic capacity
C) Minimal inhibitory concentration
D) Sensitivity

Question 37

Which of the following is a cause of drug-specific resistance in disease-causing organisms?

A) inappropriate hygiene
B) nosocomial infection
C) poor immunity
D) indiscriminate nonmedical use of antimicrobials

Question 38

EMB agar is an example of a ________ medium.

A) selective
B) differential
C) selective and differential
D) neither selective nor differential

Question 39

________, periodic reports on the susceptibility of clinically isolated organisms to the antibiotics in current local use, are particularly valuable for tracking the emergence of new antibiotic-resistant strains of pathogens.

A) Antibiotic susceptibility plates
B) Antibiograms
C) Direct agglutination reports
D) Histograms

Question 40

Antibody titer can be measured by

A) negative microscopy.
B) agglutination.
C) plate counts done after isolating the pathogen.
D) polymerase chain reaction.

Question 41

Why are secondary or ʺboosterʺ reimmunizations given?

A) Secondary immunizations are necessary for an innate immune response.
B) Secondary reimmunizations produce a secondary immune response and boost antibody titers.
C) Secondary reimmunizations produce a phagocytic immune response that is longer lasting than the primary immune response.
D) Frequent secondary reimmunizations are needed because the immune system doesnʹt remember antigens for more than a few years.

Question 42

How are infections caused by the drug-resistant Neisseria gonorrhoeae treated?

A) with β-lactamase-resistant antibiotics
B) with tetracycline
C) with synthetic analogs of tetracycline
D) with vancomycin

Question 43

Obligately anaerobic normal flora are found in ________, which is/are an anoxic habitat(s) of the body.

A) the kidneys
B) the skin
C) portions of the oral cavity
D) the lungs

Question 44

The use of special culture media and incubation conditions to isolate microorganisms from samples is known as a(n)

A) differential culture.
B) selective culture.
C) enrichment culture.
D) sensitive culture.

Question 45

Which of the following immunogens is most effective as a vaccine?

A) chemically inactivated bacteria
B) dead virus
C) live virus
D) toxoid

Question 46

A positive antibody titer indicates

A) previous exposure to an antigen.
B) active infection.
C) latent disease.
D) a healthy individual.

Question 47

Hybridization requires a nucleic acid probe that binds to DNA or RNA of interest, which must be in the ________ form for hybridization to occur.

A) single-stranded
B) double-stranded
C) oligomerized
D) polymerized

Question 48

________ is used to monitor gene expression of a pathogen.

A) Reverse transcription PCR
B) Serology
C) Antigen capture assay
D) Qualitative PCR

Question 49

Methylene blue in EMB agar slightly inhibits

A) gram-positives.
B) gram-negatives.
C) viral plaques.
D) both gram-positives and gram-negatives.

Question 50

An antigen must be at least ________ amino acids long to be effective in a vaccine.

A) 5
B) 10
C) 20
D) 100

Question 51

Indirect EIA is used to detect

A) antigens.
B) antibodies.
C) viruses.
D) serum.

Question 52

The study of antigen-antibody reactions is known as

A) serology.
B) immunology.
C) toxicology.
D) epidemiology.

Question 53

Protein A has a strong affinity for

A) antigen.
B) blood.
C) protein.
D) antibody.

Question 54

A mechanism for penicillin resistance in bacteria is

A) acetylation of the antibiotic.
B) phosphorylation of the antibiotic.
C) confirmation change of the antibiotic.
D) splitting the β-lactam ring of the antibiotic.

Question 55

An attenuated strain of a pathogen

A) has lost its virulence, but may be used to create a vaccine.
B) has changed its antigens to avoid an adaptive immune response.
C) is more virulent than the regular strains and may cause septic shock.
D) is an extracellular pathogen that will be cleared by innate immunity.

Question 56

Which of the following antibiotics inhibits RNA synthesis?

A) penicillin
B) erythromycin
C) rifampin
D) azithromycin

Question 57

SYBR Green, commonly used in qPCR, binds nonspecifically to ________, indicating the presence of the PCR product.

A) ssDNA
B) dsDNA
C) ssRNA
D) dsRNA

Question 58

Which of the following can be used in creating a vaccine?

A) attenuated bacteria
B) inactivated viruses
C) recombinant proteins
D) attenuated bacteria, inactivated viruses, or recombinant proteins

Question 59

New vaccine strategies resulting from progress in biochemistry and molecular biology include the production of

A) DNA vaccines.
B) recombinant vector vaccines.
C) synthetic peptide vaccines.
D) DNA, recombinant vector, and synthetic peptide vaccines.

Question 60

An important intestinal pathogen generally acquired from contaminated food or water is

A) Clostridium perfringens.
B) Mycobacterium tuberculosis.
C) Ebola virus.
D) Escherichia coli O157:H7.

Question 61

Nucleic acid probes and immunological reagents are NOT commonly used in the clinical laboratory for the diagnosis of viral disease, because the cultivation of the virus is often difficult or even impossible.

Question 62

In the EIA test for HIV infection, the microtiter plate is coated with disrupted HIV particles.

Question 63

Many pathogens can be readily grown in laboratory culture.

Question 64

Gram stain smears of urethral exudates for the detection of Neisseria gonorrhoeae are highly specific.

Question 65

DNA vaccines are bacterial plasmids that contain cloned DNA with an antigen of interest are unlike attenuated vaccines because there is no chance of causing disease.

Question 66

Vaccines can be developed from synthetic peptides.

Question 67

The EIA test for HIV infection is a direct test for HIV envelope proteins.

Question 68

Chitin is found ONLY in fungi and insects.

Question 69

All positive HIV-EIA tests must be confirmed by another independent test, usually the HIV Western blot.

Question 70

One problem with the EIA test is the disposal of radioactive wastes.

Question 71

Salmonella is commonly associated with wound infections.

Question 72

Some infectious agents, such as Neisseria gonorrhoeae, do NOT elicit a systemic immune response.

Question 73

What is the drawback of live attenuated vaccines?

A) They require more secondary reimmunizations than other vaccines.
B) They are not effective in adults.
C) They do NOT provide a long-lasting secondary immune response.
D) They can cause disease in some immunocompromised individuals.

Question 74

Nucleic acid probes are used to detect the presence of particular sequences of DNA.

Question 75

The causal agents of urinary tract diseases are often members of the normal flora.

Question 76

A recombinant-vector virus would still be effective if the vaccinia virus is unable to express the cloned gene as an antigenic protein.

Question 77

In cases of suspected foodborne or waterborne infections, fecal samples should be inoculated into a variety of selective media.

Question 78

When using the EIA test for HIV screening, BOTH false negative and false positive results are possible.

Question 79

Hydrogen sulfide production is assayed by growth in a medium containing ferric iron (Fe3+).

Question 80

At this time, EIA tests are too difficult for routine diagnoses.