Deck 28: Clinical Microbiology and Epidemiology

Question 1

Shigella sonnei is the cause of an infection commonly seen in infant day-care facilities due to

A) a high prevalence of the microbe in young children.
B) its ability to contaminate and grow on plastic toys.
C) its inherent antimicrobial nature (it is bleach and cleaning-product resistant).
D) diaper changes and hands not being properly washed.
E) Gram-positive cell wall structure making the bacteria environmentally resistant.

Answer 1

D

Question 2

A person who begins to exhibit symptoms of bronchitis and bacterial pneumonia after recovering from the flu would be exhibiting

A) drug resistance.
B) antiviral susceptibility.
C) underlying immunodeficiency.
D) biological meltdown.
E) disease sequelae.

Answer 2

E

Question 3

The diagram shown below shows information relative to Gram-negative rods. We CANNOT consider this diagram to be a(n)

A) example of tests available on an API 20E strip.
B) algorithm.
C) dichotomous key.
D) example of tests used to determine which type of Enterobacteriaceae an unknown might be.
E) random collection of tests for Gram-negative bacteria.

Answer 3

E

Question 4

Haemophilius influenzae requires ________ and ________ for confirmatory growth of an organism in vitro.

A) catalase; oxidase (N disk)
B) Eosin-Methylene Blue (EMB) agar; MacConkey agar
C) citrate; bile salts
D) hemin (X factor); NAD (V factor)
E) phenylalanine; ortho-Nitrophenyl-b-galactoside (ONPG)

Question 5

When sampling clinical specimens to determine the cause of a disease, samples are often plated on selective media. The reason for this is to

A) initiate an epidemiological investigation.
B) prevent the growth of normal flora.
C) determine the antibiotic resistance prior to isolation of the pathogen.
D) prevent aerobes from growing.
E) ensure proper biosafety procedures.

Question 6

In the figure shown below, we see someone wearing a specific biosafety suit. This suit would NOT be required for studying a(n)

A) outbreak of a lethal disease with no known etiological agent.
B) Ebola outbreak.
C) anthrax outbreak.
D) biosafety level 4 agent.
E) lethal disease with no known treatment or vaccine.

Question 7

A Gram-negative diplococcus result on a laboratory test would rule out all of the following bacteria EXCEPT

A) Neisseria gonorrhoeae.
B) Listeria monocytogenes.
C) Staphylococcus epidermidis.
D) Haemophilus influenzae.
E) Escherichia coli.

Question 8

Laboratory analysis of a patient suspected to have bacterial meningitis would be performed with which type of sample?

A) urine sample
B) blood draw
C) throat swab
D) sputum sampling
E) lumbar puncture

Question 9

Chocolate agar is considered ________ in comparison to blood agar.

A) more nutrient rich (capable of growing a greater variety of bacteria)
B) less nutrient rich (capable of growing fewer variety of bacteria)
C) equally nutrient rich (since they both contain red blood cells)
D) a chemically defined media (whereas blood agar is not)
E) better for determining hemolytic bacterial reactions

Question 10

The figure below shows cells stained bright fuchsia. This stain is called a(an) ________ and is used to stain ________.

A) Gram stain; Bacillus anthracis
B) Gram stain; Mycobacterium sp.
C) acid-fast stain; Mycobacterium sp.
D) acid-fast stain; Bacillus anthracis
E) Ziehl-Neelsen; Bacillus anthracis

Question 11

The Lancefield groupings are for ________ bacteria and are based on ________.

A) Streptococcus; carbohydrate peptidoglycans
B) Escherichia; lipopolysaccharides
C) Staphylococcus; peptidoglycan amino acids
D) Neisseria; hopanoids
E) Pseudomonas; optochin sensitivity

Question 12

Hektoen agar will grow all of the following microorganisms EXCEPT

A) Klebsiella pneumoniae.
B) Escherichia coli.
C) Salmonella enteritidis.
D) Shigella sonnei.
E) Streptococcus pneumoniae.

Question 13

A person exhibiting glomerular nephritis and rheumatic fever must have had what type of previous infection?

A) Shigella sonnei
B) Escherichia coli
C) Streptococcus pyogenes
D) Treponema pallidum
E) Mycobacterium tuberculosis

Question 14

Which of the following clinical specimens would be expected to be sterile in a healthy individual?

A) blood
B) urine
C) sputum
D) stool
E) skin and wound swabs

Question 15

The cause of the infection from which a patient suffers is best known as the

A) clinical agent.
B) etiological agent.
C) pathogenic culprit.
D) epidemiological agent.
E) antibiotic menace.

Question 16

Catheterization would be an appropriate method of microbial collection for

A) Streptococcus pneumoniae (lung infection).
B) Escherichia coli (UTI infection).
C) Shigella dysenteriae (GI infection).
D) Propionibacterium acnes (skin infection).
E) Helicobacter pylori (stomach infection).

Question 17

An abscess caused by the anaerobic species Clostridium perfringens would best be collected and transported by

A) aspiration into an oxygen-filled tube.
B) swabbing onto blood agar media.
C) aspiration into a nitrogen-filled tube.
D) draining with a catheter.
E) draining into a syringe.

Question 18

Catalase-positive organisms such as ________ produce ________ as end products when exposed to hydrogen peroxide.

A) Streptomyces; KCl and CO₂
B) Streptococcus; H₂O₂ and H₂O
C) Lactobacillales; CO₂ and O₂
D) Stachybotrys; HOCl and H₂O
E) Staphylococcus; H₂O and O₂

Question 19

Collection of specimen samples from places on or in the body that contain normal flora usually requires

A) initial plating on nonselective media.
B) direct Gram staining.
C) initial plating on selective media.
D) direct PCR identification.
E) immunofluorescent staining.

Question 20

A bacterial diagnosis of Mycobacterium avium in a sputum sample from an AIDS patient would be best determined by which method?

A) blood agar culture
B) acid-fast (Ziehl-Neelsen) staining
C) MacConkey agar culture
D) Gram staining
E) bacitracin susceptibility

Question 21

Eukaryotic parasites, such as Giardia lamblia, are usually diagnosed by

A) immunofluorescence.
B) PCR.
C) RFLP.
D) biochemical testing.
E) direct microscopy.

Question 22

A hemolysis reaction (on a blood agar plate) with an unidentified colony that results in a green zone due to oxidized iron in nonlysed red blood cells would be called

A) beta-hemolytic.
B) nonhemolytic.
C) gamma-hemolytic.
D) alpha-hemolytic.
E) epsilon-hemolytic.

Question 23

Symptoms of headache, fever, stiff neck, and confusion in combination with mosquito bites can indicate which viral infection?

A) Ebola
B) West Nile
C) influenza
D) rabies
E) HIV

Question 24

Point-of-care diagnostics are advantageous for all of the following reasons EXCEPT

A) culturing is not required.
B) therapy can begin sooner.
C) patient compliance is improved.
D) antibiotics can be prescribed more effectively.
E) lower risk of spreading infection.

Question 25

As point of care (POC) tests are developed, two concerns are sensitivity and specificity. Which of the following statements are true with respect to these terms?

A) Sensitivity deals with how much you can dilute the sample to get a result, whereas specificity deals with how much you dilute a control serum to get a result.
B) Sensitivity deals with how many false positives you get, whereas specificity deals with false negatives.
C) Sensitivity deals with distinguishing between closely related samples such as group A Streptococcus versus group B Streptococcus. Specificity quantitates those differences.
D) Sensitivity deals with how often a test is positive when the patient has the disease, whereas specificity deals with how often the test is negative when the patient does not have the disease.
E) The sensitivity and specificity of a test must be confirmatory or the test is useless.

Question 26

RNA sensors can be used to detect pathogens such as ZIKA virus. The steps below are steps used in testing for ZIKA virus. Which has the required steps in the correct order? 1- LacZ gene product is detected via a color change.
2- DNA is added to an RNA switch that has a hairpin to block transcription of lacZ.
3- Multiple copies of DNA matching ZIKA are produced.
4- In the presence of the ZIKA-trigger RNA, the "toehold" switch is bound and releases the lacZ rbs and start codon so transcription can occur.
5- Reverse transcriptase is used to produce cDNA from the ZIKA RNA.

A) 5-2-4-1-3
B) 3-2-4-1-5
C) 5-4-3-2-1
D) 1-2-3-4-5
E) 5-3-2-4-1

Question 27

The figure shown below is a picture of a gel with multiplex PCR products from Clostridium botulinum isolates. Lane 1 contains DNA molecular weight markers and lanes 2-5 are positive strains as controls for toxins type A, type B, type E, and type F, respectively. Based on the bands shown, what can we say about the isolate results in lane 6?

A) The isolate in lane 6 produces all four toxins but not endotoxin.
B) The PCR products from isolate in lane 6 are consistent with that isolate having toxins A, F, and B but not E.
C) The isolate in lane 6 produces all four toxins.
D) There is no band for endotoxin in lane 6 but the isolate makes three other toxins.
E) The gel shows definitive proof that this strain produces three toxins.

Question 28

The figure below shows the mass to charge ratios of two pathogenic Neisseria sp. The molecule being measured is ________ and the technique being used is ________.

A) protein; riboswitch sensor
B) protein; MALDI-TOF-MS
C) DNA; riboswitch sensor
D) DNA; MALDI-TOF-MS
E) RNA; riboswitch sensor

Question 29

An antigen-capture ELISA could be looking for all of the following in a person who is presumed to have a severe acute lung infection EXCEPT

A) mycobacterium antigens.
B) SARS antigens.
C) Haemophilus sp. antigens.
D) pneumococcal antigens.
E) anti-influenza antibodies.

Question 30

Which of the following organisms falls within biosafety group category II?

A) Ebola virus
B) SARS
C) Mycobacterium tuberculosis
D) Escherichia coli strain K-12
E) Campylobacter jejuni

Question 31

Lowenstein-Jensen agar is used to culture ________ bacteria.

A) all Gram-negative
B) beta lactase-producing
C) mycolic acid-containing
D) all Gram-positive
E) toxin-producing enteric

Question 32

A serum antibody ELISA would be looking for which of the following in a person who is presumed to have a necrotizing fasciitis infection?

A) anti-group A streptococcal antibodies
B) antimeningococcal antibodies
C) group A streptococcal-specific antigens
D) enzyme-linked antibody
E) anti-group B streptococcal antibodies

Question 33

Fluorescent antibody staining works well for clinical diagnosis on what types of antigens?

A) ribosomal
B) cytoplasmic
C) nuclear
D) capsular
E) plasmid

Question 34

Which of the following genera of bacteria would NOT change the color of N,N,N',N'7' -tetramethyl-p-phenylenediamine to purple/black upon exposure?

A) Salmonella
B) Brucella
C) Pseudomonas
D) Bordetella
E) Campylobacter

Question 35

Humans are an incidental (dead-end) host in which clinical disease?

A) West Nile virus
B) Mycobacterium tuberculosis
C) Streptococcus pyogenes
D) Staphylococcus aureas
E) picornavirus

Question 36

Which of the following is NOT true of newer clinical techniques compared to conventional techniques that require culturing?

A) The new techniques require no special equipment or training.
B) They require less time since bacteria do not have to grow.
C) Some of the newer techniques can be quantitated.
D) Some newer molecular techniques can be applied to viruses and unculturable bacteria.
E) They may rely on the presence of DNA, RNA, antigens or other proteins, and antibodies for detection of the pathogen.

Question 37

A proper course of action for a patient presenting with Ebola would be

A) quarantine and laboratory determination of Ebola IgG antibodies.
B) vaccination and laboratory growth of Ebola in culture.
C) course of antibiotics and laboratory determination of Ebola antigen.
D) antiviral therapy followed by a course of antibiotics.
E) in-home supportive therapy and laboratory PCR detection.

Question 38

Direct fluorescent staining of infected tissue samples taken from a patient allows for rapid identification under what circumstances?

A) hard-to-culture organisms
B) protist infections
C) Gram-negative organisms
D) intracellular infections
E) metabolically active organisms

Question 39

Most point-of-care diagnostics rely on

A) immunochromatographic assays.
B) Qt-polymerase chain reaction.
C) ELISA kits.
D) immunofluorescence.
E) API platforms.

Question 40

PCR-based detection of a person thought to have HIV would require all of the following EXCEPT

A) primers specific for HIV genes.
B) a thermocycler.
C) HIV agar media.
D) gel electrophoresis.
E) HIV genome isolation/extraction.

Question 41

Tuberculosis has become a reemerging pathogen today in large part due to

A) increased incidence of HIV infection.
B) airline travel reducing geographical distances.
C) surge in reservoir animal populations carrying the disease to humans.
D) strict compliance with drug regimens.
E) concurrent increases in hepatitis C infection.

Question 42

Which infectious disease is on the CDC bioterrorism list due to the general population NOT being vaccinated for this disease since the 1970s?

A) bubonic plague
B) rabies
C) smallpox
D) tuberculosis
E) Machupo virus

Question 43

Molecular screening is now being used to detect individuals with early stages of TB because

A) skin testing is unreliable and needs refrigeration that many countries may not have.
B) vaccination with Bacille Calmette-Guérin does not protect against multidrug resistance.
C) many countries do not have disposable needles for skin testing.
D) it can detect infection earlier than chest X-rays and sputum sampling.
E) it can be used more safely on children with the disease.

Question 44

Collaborators necessary to solve and control a human epidemic include

A) epidemiologists.
B) ecologists.
C) veterinarians.
D) scientists.
E) epidemiologists, ecologists, veterinarians, and scientists.

Question 45

A defining commonality between biosafety risk group II handling techniques and a biosafety IV facility would be the need for

A) a personal positive-pressure suit.
B) an isolation facility.
C) a negative-pressurized lab space.
D) directional air flow in the room.
E) the use of aseptic techniques.

Question 46

John Snow, the "father of epidemiology," is known for deducing the source of which etiologic agent in the 1854 London outbreak?

A) Shigella dysenterie
B) Vibrio cholerae
C) Haemophilius influenzae
D) Giardia lamblia
E) Yersinia pestis

Question 47

The correct definition of "bioweapon" is any

A) agent categorized as a biosafety level IV organism.
B) infectious disease spread person to person with a low mortality rate.
C) agent causing widespread psychological trauma, with few casualties.
D) microbial agent or pieces of microbes that can be loaded into bombs.
E) infectious agent or toxin that has a high virulence and/or mortality rate.

Question 48

Which of the following would NOT be a task for an epidemiologist?

A) keeping track of the incidence and prevalence of disease and reportable diseases
B) helping to assess the effectiveness of treatments of preventions
C) performing basic research to understand how the etiological agents causes symptoms
D) coordinating global measures to minimize an outbreak or epidemic
E) finding patient zero

Question 49

Bubonic plague is endemic in many countries in Africa and in the former Soviet Union. This indicates that

A) plague was once a huge problem and has now evolved to not cause infection.
B) plague has been eradicated from these areas.
C) large numbers of people are infected in these areas and it is spreading.
D) the disease is always present in the population at a low frequency.
E) human-to-human contact transfers plague.

Question 50

Compare and contrast the dichotomous key approach to bacterial determination with the seven-digit-number approach when using the API strip system.

Question 51

Looking at the laboratory results presented here, what three interpretations can be made?

Question 52

The use of a laminar flow hood when studying the organism Francisella tularensis is an example of level ________ biological safety.

A) 0
B) I
C) II
D) III
E) IV

Question 53

In determining the bacterial etiology of a patient with an infection, the first laboratory test should be what, and why? What type of testing would then follow?

Question 54

Which of the following is a reportable, biosafety level III organism that causes low-grade fever, chills, headache, and malaise followed by a dry cough, shortness of breath, and chest heaviness?

A) methicillin-resistant Staphylococcus aureas
B) Plasmodium falciparum
C) West Nile virus
D) Bacillus anthracis
E) Yersinia pestis

Question 55

Describe the general protocol used to diagnose a patient with a Salmonella typhimurium infection (from collection to testing).

Question 56

Which of the following criteria is NOT required in order for a mosquito-borne virus to become endemic in a new location?

A) A person infected elsewhere must travel to the new area.
B) A local mosquito must bite a person who has the disease in order to spread it to someone else.
C) The virus must move from an Aedes mosquito to another insect vector.
D) The virus must move from the local mosquito to a local animal that can then serve as a reservoir.
E) The local mosquito must bite another human in that area and give him or her the disease.

Question 57

Gaëtan Dugas is frequently referred to as the individual who began the spread of HIV within the gay male community in North America in the 1970s. In epidemiology, he is known as

A) the first patient.
B) the superspreader.
C) patient 1.
D) the index case.
E) patient zero.

Question 58

Looking at the laboratory results presented here, what three interpretations can be made?

Question 59

The following are all concerns of the influence of global climate change on infectious diseases EXCEPT that

A) global climate change will increase the incidence of antibiotic resistance.
B) the habitat of insect vectors increases in size as temperatures rise.
C) extending ranges of vectors may bring them in contact with new hosts.
D) climate change may bring more flooding, thus increasing the spread of gastrointestinal illness.
E) infectious disease cycles may speed up or extend through longer portions of the year.

Question 60

The graph shown below diagrams the number of cases of a disease versus time. The high peak near the right-hand side would be considered a(n)

A) prevalence.
B) incidence.
C) endemic.
D) epidemic.
E) pandemic.

Question 61

Compare and contrast the use of the serum antibody ELISA with the antigen-capture ELISA in the detection of Ebola.

Question 62

Describe what the One Health Initiative is and the role it played in the 2006 outbreak of food-borne O157:H7 in spinach.

Question 63

Compare and contrast the handling of rabies (a category III organism) with Lassa fever (a category IV organism).

Question 64

As a disease detective investigating an outbreak in the cafeteria of your college, what would be some of the first steps you would need to take to begin your investigation, other than laboratory testing?

Question 65

The clinical microbiology laboratory just received a sputum (deep-lung) sample that so far has been very slow-growing in nonselective agar, as well as not Gram stainable. What tests should be performed next, and why?

Question 66

How would a serum antibody ELISA work in the detection of Lyme disease?

Question 67

How were Koch's postulates modified in the discovery of Tropheryma whipplei, the causative agent of Whipple's disease?

Question 68

How can reverse transcriptase PCR (RT-PCR) be used to determine the presence and viral load of HIV infection?

Question 69

Compare and contrast the use of point-of-care rapid tests as diagnostic methods in doctors' offices.

Question 70

Once cultured, bacteria from septic infections or urine can be quickly identified by MALDI-TOF-MS. What is this technique and how does it work?

Question 71

Describe the chain of command that is followed when a patient sees his or her doctor and is diagnosed with a reportable disease such as listeriosis.

Question 72

Compare and contrast the epidemiological terms "endemic," "epidemic," and "pandemic." Give an example of each to support your answer.

Question 73

How does a multiplex PCR reaction differ from a traditional PCR detection method? In addition, describe an example of how multiplex can be used in diagnostics.

Question 74

Why are clinical viral diseases more challenging to diagnose than are clinical bacterial diseases?

Question 75

How have changes within our human culture caused new diseases to emerge? Explain your answer using a specific example that supports your statements.