Microbio Labs

B

Comparing the six organisms that are represented in lanes A-F of this PFGE gel, the best conclusion is: A. The organism in lane D has the biggest B. The isolates in lanes B and C are most closely related to one another. C. The organism in lane F encodes the least number of proteins. D. The organisms in lanes D, E, and F make larger proteins than the organisms in lanes A, B, and C.

D

For each of the following, the arrow points to the template strand. Which one will result in a SILENT mutation when the template strand is transcribed by RNA polymerase and the mRNA codon is translated? A. 3'...GTA...5' <-- mutates to 3'...GTC...5' <-- 5'...CAT...3' 5'...CAG...3' B. 3'...TCT...5' <-- mutates to 3'...TCA...5' <-- 5'...AGA...3' 5'...AGT...3' C. 3'...CAT...5' <-- mutates to 3'...GAT...5' <-- 5'...GTA...3' 5'...CTA...3' D. 3'...GGA...5' <-- mutates to 3'...GGG...5' <-- 5'...CCT...3' 5'...CCC...3'

C

Here is an example of a genetic map from a typical bacterium that shows how genes and operons might be arranged along one small portion of its DNA. Which of these letters A-D marks an operon on this portion of DNA? A. A only B. A and B C. All but B are operons D. C and D

Only takes one

How many bacteria must be present for there to be the threat of infection?

Diagram A: Immediately following the destain of acid alcohol Diagram B: Immediately following the hot carbol fushin staining Diagram C: Immediately following the counterstain with methylene blue

Refer to the diagram above to match up the correct result to each step in the Ziehl-Neelsen Acid Fast Stain procedure:

A

Select the WBC type shown in the peripheral blood smear. A. PMN (neutrophil) B. Lymphocyte C. Eosinophil D. Monocyte

Glycoysis, Krebs cycle, ETC

Strict aerobes use what kind of pathways?

Glycolysis and fermentation

Strict anaerobe use what kind of pathways?

Eukaryotes, they have a nucleus and similar organelles (Protozoan) Fungi are eukaryotic but have a chitinous outer membrane

Which groups (if any) have cell types that have the most common with our human cell type? Why?

D

Which morphology above is considered a vibrio? A.B B.D C.F D.H

Largest--> Smallest Fungi (mm), Protozoan (um), Bacteria (200nm-10um), Virus (10-100nm)

Which of the 4 organism types are the biggest? smallest?

C

Which of the above photos shows a positive PPD or tuberculin skin test? A B C D

A

Which of the following descriptions matches the Gram stain shown the best? A. Gram+ cocci B. Gram+ bacilli C. Gram- bacilli D. Gram- diplococci

D

Which of the following differential Gram stain reactions would best describe the bacterium in this figure? A. Spore stain positive B. Acid Fast positive C. Gram-positive D. Gram-negative

C

Which of the following is prokaryotic? A. fungus B. protozoan C. bacterium D. virus

D

Which of the following statements about hemolysins is true? A. Red blood cells are not the main target in the body for hemolysins. B. To identify hemolysis, you must look around isolated colonies. C. Hemolysins help bacteria evade the bodies immune system. D. All of the above are true.

A

10 medical students were tested and found to have Staphylococcus aureus in the nasapharynx (nose). Their isolates were further tested using PCR to detect methicillin resistance. If 3 of the students were found to have methicillin-resistant S. aureus, how many students had results like result A above? A. 7 students B. 3 students C. 1 student D. All students

C

A 7 year-old girl was seen by her pediatrician for a fever and sore throat. A strep screen was performed yielding the above results. Check the ONE statement that would be true of the organism most likely the cause of this girl's symptoms. A. This girl has strep throat caused by Streptococcus pyogenes. B. This girl does not have strep throat and should be sent home with no treatment. C. This girl MAY have Group A strep and the culture should be performed to verify whether or not she needs treatment. D. The test is invalid and needs to be repeated.

B

A patient is suffeing from an unexplained fever. They have a white count of 11,000 WBC/dl (normal = 5,000-10,000 WBC/dl). The differential shows 50% lymphocytes. What is the most likely cause of the fever? A. A parasitic infection. B. A viral infection. C. A bacterial infection. D. None of the above.

E.Coli (a facultative anaerobe)

A patient presents with a ruptured appendix and peritonitis. The gram- negative anaerobe, Bacteroides fragilis, is isolated. Which of the following would, in a polymicrobial infection with this microbe, be most likely to have established the conditions needed for this infection?

Staphylococci (a facultative anaerobe)

A patient presents with community-acquired pneumonia, secondary to aspiration of oral secretions. The gram-negative anaerobe, Prevotella, is isolated. Which of the following would, in a polymicrobial infection with Prevotella, is most likely to have established the conditions needed for this infection?

C

A person with a latent Mycobacterium tuberculosis infection like our daycare manager A. Is symptomatic B. Is AFB smear positive C. Is likely to have a positive tuberculin skin test (PPD) D. Does not require treatment

C

A. Virus B. Bacteria C. Fungi D. Protozoan E. Worm Eggs

B

Above is an example of an ELISA. Which component comes from the patient? A. The green component B. The orange component C. The blue component D. None of the above

Glycolysis and fermentation

Aerotolerant anaerobe use what kinds of pathways?

5

Aerotolerant anaerobes growing in a TSA agar deep will have an appearance similar to tube.... 1 2 3 5

B

After viewing the results of the Quick Vue Strep test for the following three patients, what would your next step be for patient B? A. Do not treat with antibiotics and tell the patient to gargle with warm salt water B. Treat with antibiotics for Group A Strep C. DO NOT treat with antibiotics, but streak a second throat swab on a blood agar plate with a bacitracin disc

C

Based on your work in Activity 20, which of the media below would you classify as differential but not selective? A. TSA B. MacConkey C. Blood D. Campylobacter

Glycolysis, Krebs cycle, ETC, Fermentation

Facultative anaerobe use what kind of pathways?

C

If a gram-positive cocci was beta-lactamase negative by the phenotypic assay beta-lactamase test, what else can you assume about this organism? A. That the organism is a MRSA B. That the organism will also be penicillin resistant. C. That the organism will also be penicillin sensitive. D. That the organism will be resistant to all antibiotics used to treat gram-positive infections.

No, does not have thin peptidoglycan and 3 layers, just pink

If a protozoan stains pink when performing a gram stain, is it gram-negative?

B

If a urine culture was performed using a 0.01 ml calibrated loop, and the urine sample was collected by supra-pubic aspirate, if it produced a 10 colonies on the blood agar plate the culture would A. have to be recollected. B. be considered significant and a complete workup would be done. C. be considered contaminated and discarded. D. would have been performed incorrectly.

B

If the original sample contains 1.2x10^7 CFU/ml, how many colonies would you expect to see on plate D? A. 12 B. 120 C. 1200 D. 1

Use an electron microscope to determine the number of membrane layers, stain the bacteria according to the gram stain protocol and view at 1000X oil

If you wanted to categorize a newly isolated bacteria as gram-positive or gram-negative, what steps would work?

A

In Mystery Case 1, which test determined that the father was infected with a MRSA strain? A. Kirby Bauer B. catalase C. Gram stain D. Beta hemolysis

A?

In Mystery Case Study 4, after growing patient specimens on several different types of selective and differential growth media and performing a parasite and ova exam, which of the following organisms was not ruled out as a possible cause of the foodborne illness? A. Norovirus B. Salmonella C. Shigella D. Giardia

A

In the Mystery Case at the Dialysis Center, what was the cause of the patient's infection? A. Serratia liquefaciens B. Pseudomonas aeruginosa C. Staphylococcus aureus D. Salmonella

A

In the above ELISA, the serum samples from Patients A-F are placed in rows A-F, and are being tested for the presence of antibody to a rare fungal pathogen. Column 11 is the negative control and column 12 is the positive control. A 1:2 dilution of the patient serum has been placed in column 1, and is further diluted 1:2 out to column 9. A titer of 32 is considered positive. Which of the following statements is NOT true? A. C, D, and E are infected B. C and E are infected C. B is not infected

Yes, just not anaerobic (A count needs to be 10^7 to be visibly turbid)

Is it possible that tubes could appear clear (non-turbid) and still contain viable bacteria?

A

Is the type of hemolysis seen above indicative of strep throat caused by Streptococcus pyogenes? A. Yes, it is beta-hemolytic and bacitracin sensitive. B. No, Streptococcus pyogenes is bacitracin resistant. C. No, Streptococcus pyogenes is gamma hemolytic. D. Yes, Streptococcus pyogenes is alpha-hemolytic.

D

One group of students wanted to test a few disinfectants. They prepared TSA agar plates with four disinfectant soaked discs. Their resulting plates are shown in Figure 1. Which disinfectant was the most effective disinfectant against both organisms? A. Quats B. pHisoHex C. Lysol D. Chlorine

C

Our victim has AB positive, what blood components above match? A. Unit 7 and 11 B. Units 4, 5, 6 and 7 C. All of the units are compatible D. Units 3 and 9 only

D

Peptidoglycan is present in.... A. all living cells B. Gram-positive bacteria only C. Gram-negative bacteria only D. most bacterial cells

B

The DNA double helix shown here is part of a bacterial gene, TRUE only one of the statements below can be regarding this small DNA piece--which one? A. If we assume that a "T" (thymine) defines the 5' end of a strand, then the sequence of nucleotides near the middle of the diagram is 5'AGCC-3'. B. If we assume that the base, T (thymine) defines the 5' end of one strand in the diagram, then the base, cytosine (C) is at the 3' end. C. If we assume that a "T" (thymine) defines the 5' end of one strand, then an "A" (adenine) defines the 5' end of its strand, too D. The amount of DNA shown in the diagram is equivalent to 11 amino acids when transcribed and translated into protein.

D

The bacteria in tubes A-D can ALL utilize which metabolic pathways? A. Fermentation B. Electron transport C. Krebs cycle D. Glycolysis

A

The diagram illustrates a moment in a bacterial cell during which transcription and translation are occurring. Which statement below correctly matches the position of one of the yellow icons (heart, moon, star, etc.) to its role in coupled transcription and translation? A. The sun is located just above the RNA polymerase which was the first one to begin transcribing this gene. B. Each lightning bolt is located next to a sequence of mRNA that is totally different from the sequences next to the other lightning bolts. C. The heart shows the location of the promoter sequence D. The moon shows the strand that is complementary to the mRNA strands. E. The smiley face shows where a stop codon would be encoded for this gene.

B

The diagram shows a stretch of DNA from a bacterial chromosome; at the top of the diagram, we're zoomed in on the portion of the DNA that includes the code for a stop codon (highlighted). When this DNA is transcribed and translated, which amino acid will be the final one in the protein (that is, the last amino acid to be put in place before the ribosome hits the stop codon)? A. His (H) for histidine B. Tyr (Y) for tyrosine C. Pro (P) for proline D. Gly (G) for glycine E. Gin (Q) for glutamine F. Val (V) for valine

D

The genetic material of which of the following types of viruses must be transcribed into a (+) sense RNA by the viral enzyme RNA-dependent RNA polymerase before the genes can be translated by host cell ribosomes? A. Positive sense RNA B. Double stranded DNA C. Double stranded RNA D. Negative sense RNA

B

The initial concentration of bacteria in tube A is 6x10^5 CFU/ml, using this info, answer the following question. What is the concentration of bacteria in tube C? A. 6x10^2 CFU/ml B. 6x10^3 CFU/ml C. 6x10^5 CFU/ml D. 6x10^4CFU/ml

B

This virulence factor is attached to the bacterial cell and protects it from phagocytosis. A. Coagulase B. Capsule C. DNase D. Biofilm

D

This virulence factor protects from phagocytosis and inhibits penetration of antibiotics without attaching to the bacterial cell. A. Coagulase B. Capsule C. DNase D. Biofilm

B

To survive and replicate, a virus must first: A. obtain proper nutrients and moisture. B.bind to an appropriate host cell. C. mate with a compatible virus of its own species. D. acquire genes from any cell living nearby.

C

Two patients are sharing a hospital room and develop infections at the same time. Isolates obtained from both patients are gram-positive cocci. When grown on sheep's blood agar, the isolate from patient A produces a distinctive transparent zone in the agar around each colony. The isolate from patient B also produces a transparent zone in the agar around each colony. What conclusion can be drawn from these results? A. They have infections with the same organism. B. Their infections are unrelated. C. They have infections that may or may not be caused by the same organism. D. While the causative organism may be the same, considerable mutations will have occured when the organism spread from 1 patient to the other. E. No answer text provided.

B

Two patients are sharing a room in a hospital and develop IVcatheter-related infections at the same time. Isolates obtained from both patients are chain-forming, grampositive cocci. When grown onsheep's blood agar, the isolate from patient A produces a distinctive greenishzone in the agar around each colony. The isolate from patient B produces a clear zone in the agar around eachcolony. What would be appropriate for the hospital staff to conclude? A. That the two room-mates have become nosocomially infected with the same microbe. B. That Patient A has an Alpha-hemolytic, gram-positive cocci; and Patient B has a beta-hemolyitic gram-positive cocci that are different species. C. That Patient A has a gamma-hemolytic, gram-positive cocci; and Patient B has an alpha-hemolyitic gram-positive cocci that are different species. D. That Patient A's Alpha-hemolytic, gram-positive cocci; and Patient B's beta-hemolyitic gram-positive cocci are genetically identical.

D

Using an E-test, the MIC for an isolate from a patient suffering from a tooth abscess was reported as seen above. If the concentration of antibiotic at the site of the abscess is 0.5 micrograms/ml, what effect will this concentration of antibiotic have on the organisms at the site of the abscess? A. The antibiotic will inhibit the organisms. B. The antibiotic will kill half of the organisms. C. The antibiotic will kill the organisms. D. The organisms will be unaffected.

A

Virulence factors A. give the pathogen an advantage at the site of infection. B. are always necessary for a pathogen to cause infection. C. cannot be used to identify pathogens. D. have no effect on host defenses.

(1) Gram reaction (+/-) (2) Morphology

What are the two key parts of a gram stain result?

C

What blood types are compatible with the above victim? A. O negative and A positive B. O positive and AB negative C. O negative and A negative D. A positive and B negative

A

What conclusion can be made about the identity of the isolate that grew in this urine culture? A. The organism is gram-positive. B. The organism is gram-negative. C. The organism has to be Staphylococcus aureus. D. You can make no conclusions from the information shown.

D

What does 6X105 CFU/ml mean? A. 600 CFU/ml B. 6,000 CFU/ml C. 60,000 CFU/ml D. 600,000 CFU/ml

B

What is the blood type for the above patient? A. B+ B. A- C. O- D. A+

Fermentation pathways (H2 or CO2)

What sort of metabolic pathways produce gas?

A

What type of hemolysis is shown in the figure? A. Alpha B. beta C. Gamma D. Delta

D

What type of viral structure is pictured in this figure? A. Naked, icosahedral caspid B. Naked, helical capsid C. Enveloped, icosahedral capsid D. Enveloped, helical capsid

D

What type on infection is indicated by the diagram? A. Persistent B. Chronic C. Latent D. Acute

strict anaerobe

What type os TSA tube produces gas?

D

What will not be seen in a normal peripheral blood smear? A. Red cells B. White cells C. Platelets D. Antibodies

B

When you perform ABO, you react patient red blood cell _________ with known manufactured ___________ and look for agglutination or clumping. A. Antibody; antigen B. Antigen; antibody C. Macrophages; antigen D. Monoclonal antibodies; anti-IgG antibodies

2

Which RNA nucleotide would bind to the C on the DNA strand? 1 2 3 4 5 6 7

C

Which of the following statements is true regarding HIV testing? A. A microtiter HIV assay is used to confirm previously screened samples. B. The western blot confirms HIV because it tests for multiple HIV antigens. C. The western blot confirms HIV because it tests for antibodies specific to multiple HIV antigens. D. The western blot is used to screen samples for HIV.

C

Which of the following tests is commonly used to establish the antibiotic resistance profile of a particular organism to several antibiotics at one time? A. Broth dilution B. E test C. Kirby Bauer D. Both broth dilution and E test

Bacteria

Which type of organism gives a gram stain result?

A

Why can't microorganisms develop resistance to disinfectants like they do to antibiotics? A. Because disinfectants are active against a class of host molecules, such as all proteins or lipids B. Because disinfectants are active against a specific molecule, such as an enzyme C. Because disinfectants can prevent mutations in DNA that lead to resistance D. Because bacteria are not exposed to disinfectants very often.