Exam 1: Quizzes Flashcards by Aleksandra Grigoryants

Which of the following structures would NOT be found in a prokaryotic cell:

Ribosomes in the cytoplasm
DNA
A cell membrane composed of a phospholipid bilayer
A cell wall composed of peptidoglycan
Mitochondria in the cytoplasm

Mitochondria in the cytoplasm

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The cell walls of gram-positive bacteria contain

A very thin protective peptidoglycan layer
An outer lipopolysaccharide layer
Two unique antigenic components: teichoic acid and lipoteichoic acid
All of the above are found in the cell walls of gram positive bacteria

Two unique antigenic components: teichoic acid and lipoteichoic acid

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Streptococcus pyogenes would most likely have which morphology and arrangement?

Clusters of spheres
Single rods
Chains of rods
Chains of spheres
Clusters of rods

Chains of spheres

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**In regards to nomenclature guidelines, which of the following is written incorrectly:
**
1. Streptococcus pyogenes

staphylobacillus
Staphylococcus aureus
Escherichia coli O157:H7

staphylobacillus

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Which of the following lists the steps in the Gram Staining procedure correctly?

Crystal violet, Iodine, Alcohol-Acetone, Safranin
Safranin, Alcohol-Acetone, Crystal violet, Iodine
Carbolfuchsin, Acid-Alcohol, Methylene Blue
Methylene Blue, Acid-Alcohol, Carbolfuchsin
None of these are correct

Crystal violet, Iodine, Alcohol-Acetone, Safranin

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Corynebacterium diphtheria is the causative agent behind diphtheria. However, not all C. diphtheriae bacteria produce the toxin that causes this disease. To produce the toxin, the bacteria must first become infected with a bacteriophage. The process by which bacterial genes are transferred to new bacteria by a bacteriophage is called:

Transduction
Conjugation
Replication
Transformation

Transduction

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**When bacteria are growing, they go through a stationary phase when:
**
1. the number of nonviable bacterial cells exceeds the number of viable cells.

the bacterial numbers double with each generation time.
nutrients are becoming limited and the numbers of bacteria remain constant.
they are preparing to divide.

nutrients are becoming limited and the numbers of bacteria remain constant.

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**Which of the following environmental factors influence the growth of bacteria in the laboratory?
**
1. pH

Temperature
Gaseous composition of the atmosphere
All of the above

All of the above

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**The anaerobic process carried out by both obligate and facultative anaerobes that uses an organic compound as the final electron acceptor is called
**
1. capnophilic

fermentation
microaerophilic
anaerobic cellular respiration

fermentation

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**All of the following statements are true about viruses except viruses:
**
can infect bacteria, plants, and animals.

are acellular but are surrounded by a protein coat.

do not need host cells to survive and grow.

have a genome that consists of DNA or RNA but not both.

do not need host cells to survive and grow.

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**Microorganisms that participate in symbiosis where the microorganism lives at the expense of the host (the host is harmed)
**

mutualism

indigenous microbiota

commensalism

parasitism

host interactions

parasitism

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**Which of the following “site - bacteria” combinations, would NOT be considered normal microbiota:
**

Gastrointestinal tract - Bacteriodes spp.

Oral cavity - Streptococcus mitis

Stomach - Escherichia coli

Skin - Staphylococcus epidermidis

Vagina - Lactobacillus spp.

Stomach - Escherichia coli

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**Candida albicans is a member of the resident microbiota of many people, but it may overgrow when a person is taking an antibiotic. This type of infection is called:
**

sexually transmitted infection

an opportunistic infection

symbiosis

a carrier state

a parasitic infection

an opportunistic infection

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A patient arrives at the emergency room exhibiting the following symptoms: a temperature of 102° F, low blood pressure, elevated white blood cell count, and abnormal blood clotting (DIC). Blood cultures reveal the presence of gram-negative rods. What is the likely cause of these symptoms?

Exotoxin

Endotoxin

Extracellular enzymes

Exfoliating toxin

Endotoxin

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Innate immunity consists of which of the following components?

Physical and chemical barriers, such as the skin and mucous membranes

Blood proteins that act as mediators of infection

Cells capable of phagocytosis

All of the above are part of the innate immune system.

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Which of the following is NOT a virulence factor found on/in at lease some pathogenic bacteria?

Fimbriae

Protein A

Cilia

Capsules

Ability to resist phagocytosis

Cilia

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Indirect routes of transmission of infectious disease include all of the following EXCEPT?

Airborne - aerosols suspended in the air

Water

Fomites

Sexual contact

Food

Sexual contact

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Health care-associated infections are commonly associated with:

foodborne illness.

respiratory aerosol transmission.

preexisting infections.

breaks in aseptic technique.

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What process helps public health and health care officials recognize outbreaks, increasing trends of infections, and positive effects of interventions?

Intervention

Handwashing techniques

Antimicrobial resistance

Surveillance

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**How quickly would rabies need to be reported as a disease of major public health concern? (this is true for MN and OH like the chart)
**

By the end of the next business day

Immediately

During a monthly report

By the end of the work week

It doesn’t need to be reported at all

Immediately

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Methods used to destroy all life are called

bacteriostatic

sterilization

bactericidal

disinfection

sterilization

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The most resistant microbes to heat, chemicals, and radiation are:

parasites

viruses

prions

bacteria

prions

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After working in the microbiology lab, the laboratory scientist sprayed the bench top with a chemical spray. This process will not kill all microbes, but will reduce the number of microbes, including pathogens, on this non-living surface. What is this called?

Sterilization

Antiseptic

Bactericidal

Bacteriostatic

Disinfection

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Which type of gas has commonly been used for gas sterilization of heat sensitive material in a hospital setting?

oxygen

nitrous oxide

ethylene oxide

carbon dioxide

ethylene oxide

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**What is the most common iodophor used in the U.S. for preoperative skin preparation?** calcium iodophor 95% ethanol and iodine tincture of iodine povidone iodine

povidone iodine

**Which of the following is NOT contained on a SDS ** Disposal recommendations Precautions to take while using chemical and control measures Directions for using the chemical experimentally Spill cleanup procedures Name, address, and telephone of manufacturer

Directions for using the chemical experimentally

**Which Biosafety Level is used in most hospital labs, where there is a moderate potential for encountering hazardous material?** 1 2 3 4

**Which of the following is NOT considered a major source of biological hazard for people working in clinical microbiology?** Patient samples during processing and handling Actively growing culture materials Appropriately disposed of infectious waste None of these are sources of biological hazard

Appropriately disposed of infectious waste

**Why is quality control important? ** ensures that the correct BSL is used. ensures that incidence of emerging infectious diseases is decreasing. ensures that standard precautions are followed. ensures the medical reliability of laboratory data.

ensures the medical reliability of laboratory data.

**Select the answer that best fills in the blank: 100 patients who have gonorrhea are tested for that disease and the test yields positive results in 95 and is negative in the other 5. Five of these 100 patients had false-negative (FN) test results. The _of the test is 95%** Clinical specificity Incidence Analytic specificity Clinical sensitivity

Clinical sensitivity

**Which of the following is NOT TRUE of correct specimen collection?** label the specimen accurately with the specific anatomic site and the patient information. select the correct anatomic site to collect the specimen. pack the specimen to maintain viability and prevent leakage collect the appropriate quantity of specimen. it is acceptable to collect specimens after antibiotics are administered on a routine basis.

it is acceptable to collect specimens after antibiotics are administered on a routine basis.

**Why are bone marrow, synovium, and blood specimens mixed after collection with anticoagulants?** Anticoagulants dissolve part of the bacteria's cell wall and congeal many bacteria into groups. It ensures the specimen will work when using an automated spreader device. Prevent organisms from becoming bound up in the clotted material, making them difficult to isolate. It kills all the normal microbiota and only leaves the pathogens in the specimen. It breaks down eukaryotic nuclear material, but not bacterial for nucleotide amplification tests.

Prevent organisms from becoming bound up in the clotted material, making them difficult to isolate.

**Which of the following normally has the highest level of specimen prioritization?** Feces Cerebrospinal fluid Urine Bone Sputum

Cerebrospinal fluid

**Which of the following is NOT a normal reason to reject a specimen? ** Specimen is received in the wrong preservative. The transport time was 30 minutes. All of these are normal reasons to reject a specimen The transport container is leaking. Requisition information does not match specimen label Specimen is dried up.

The transport time was 30 minutes.

**You receive a specimen through the mail from a smaller lab. The package has a small watertight vial in a larger watertight tube. The smaller tube has absorbent material around it. No other packaging is present. What was wrong with this?** The primary container does not need to be watertight. It is not necessary to have a second watertight tube to enclose the smaller vial. Absorbent material should be around the larger tube not the primary receptacle. Secondary container should be enclosed in a outer container made of fiberboard. Specimen was placed in a small watertight vial.

Secondary container should be enclosed in a outer container made of fiberboard.

**Which of the following media would be classified as nonselective and enriched?** Mannitol salt agar Eosin methylene blue agar MacConkey agar Chocolate agar CNA agar

Chocolate agar

**Which of the following media / classification pairings is incorrect?** Sheep's blood agar / Differential media CNA / Selective media MacConkey agar / Selective Media Sheep's blood agar / Selective media MacConkey agar / Differential Media

Sheep's blood agar / Selective media

**A common method to isolate individual colonies of bacteria on a culture plate is called a _plate. It allows grading of a relative concentration of organisms using four quadrants.**

Streak

Cotton swabs are the best specimen collection devise. True False

false

Both written and verbal instructions are necessary to provide patients expected to collect a clean catch urine sample. True False

true

**Which of the following is NOT a critical value in microbiology?** Positive blood culture Positive cerebrospinal fluid culture Positive acid-fast smears Streptococcus agalactiae from genital site of pregnant women at term Streptococcus pyogenes from a sterile site All of these are examples of critical values in microbiology

All of these are examples of critical values in microbiology

**If you are looking at a specimen under the 100X oil objective of a compound microscope with a 10X ocular magnification, what would be the total magnification?** 10X 60X 110X 500X 1,000X

1,000X

Which type of microscope is usually used in the clinical microbiology lab? Darkfield compound Fluorescent Brightfield compound Dissecting

Brightfield compound

**In the Gram stain technique, Safranin functions as the** Mordant Decolorizer Counterstain Primary stain

Counterstain

**Which of the following staining procedures would be used as a differential stain of infected materials to stain infected materials suspected of containing bronchoalveolar fungi? ** Leifson stain Acid-fast stain Calcofluor white stain Methylene blue stain Wright-Giemsa stain

Calcofluor white stain

**When making slides of thin materials such as urine and cerebrospinal fluid (CSF)** use the two-slide pull method to ensure evenly distributed material over the slides spread the material once, let the specimen dry, then spread another layer on top to ensure enough specimen to stain mark the area of the sample drop on the reverse side with a wax pencil and then place a drop of the specimen into the marked area dip a swab into the specimen, then roll the swab over the glass slide to ensure adequate coverage for staining

mark the area of the sample drop on the reverse side with a wax pencil and then place a drop of the specimen into the marked area

**What elements should be included in the direct examination of a microbial smear?** Only those elements pertaining to the amount of gram-positive cocci present in the specimen Only those elements useful in characterizing the specimen Only those elements of contaminating material present in the specimen Only elements pertaining to the necrosis present in the specimen

Only those elements useful in characterizing the specimen

**A cytocentrifuge is an excellent method for preparing nonviscous fluids, because** it deposits cellular elements and microorganisms from the specimen onto the surface of a glass slide as a monolayer. the sediment is mixed with 70% albumin before spreading it on the surface of a slide. the cytocentrifuge not only spreads the specimen over the surface of a slide but also stains the specimen. it concentrates the protein evenly throughout the slide surface.

it deposits cellular elements and microorganisms from the specimen onto the surface of a glass slide as a monolayer.

**You prepare cerebrospinal fluid (CSF) cultures and read the results. You notice no growth on sheep blood agar (BAP) or MacConkey (MAC) agar, but that there is growth on chocolate agar (CHOC). The Gram stain showed a gram-negative bacillus. What organism should be suspected?** Haemophilus influenzae Streptococcus pneumoniae Escherichia coli Staphylococcus aureus

Haemophilus influenzae

If a symptomatic patient presents to a physician with a bacterial infection, the physician will treat the patient with antibiotics. What role does the laboratory play in antibiotic selection if the physician has already treated the patient before receiving the laboratory results? ** The physician has only given the patient antibiotic samples, and they will only last for a couple days—until the culture results are ready and a proper prescription can be written.** Physicians will only write antibiotic prescriptions for patients who are infected with a large number of bacteria, so the laboratory needs to tell the physician which antibiotic to use to treat the patient infected with a small number of bacteria. The physician can treat the patient for bacterial infections, but if the patient has a fungal infection, the physician relies on the laboratory to tell her or him if the patient has a fungal infection. The physician expects the laboratory to affirm or reject the antibiotic choice made after the presumptive diagnosis.

The physician expects the laboratory to affirm or reject the antibiotic choice made after the presumptive diagnosis.

**Plate reading is:** a comparative examination of bacteria growing on a variety of culture media. examining the colonial morphology of bacteria on slants. determining if the inoculum is mixed. setting up biochemical tests to identify bacteria.

a comparative examination of bacteria growing on a variety of culture media.

**A commonly used medium containing lactose and bile salts that is a selective and differential medium for the isolation of gram-negative bacteria is .** Sabouraud dextrose agar Anaerobic blood agar MacConkey agar Chocolate agar

MacConkey agar

**β-Hemolysis is:** when organisms have no lytic effect on the erythrocytes in the blood agar plate. partial lysing of erythrocytes in a blood agar plate around and under the colony. complete clearing of erythrocytes in a blood agar plate around and under the colony. a pink "halo" around a colony.

complete clearing of erythrocytes in a blood agar plate around and under the colony.

**Which of the following is not used to describe the edge of colonies?** filamentous umbonate rough rhizoid irregular smooth

umbonate

**Which bacterial species is said to smell like a musty basement?** Haemophilus spp. Nocardia sp. Proteus mirabilis Pseudomonas aeruginosa Staphylococcus aureus

Haemophilus spp.

**Which of the following organisms form scumlike growth when grown in thioglycollate broth?** Gram-negative rods (Enterobacteriaceae) Pseudomonas spp. Yeast Streptococcus spp.

Pseudomonas spp.

**Why should laboratory professionals look for contamination of a specimen by normal microbiota? ** Normal microbiota always preclude the possibility of a pathogen infecting the area where they reside. Contamination of specimens with normal flora that are not collected from sterile sites diminishes the value of the culture studies. The normal microbiota will be found in clumps, and any pathogenic bacteria will be found with the normal flora. Contaminated specimens will have much amorphous debris that also goes with them.

Contamination of specimens with normal flora that are not collected from sterile sites diminishes the value of the culture studies.

**When reading stool culture plates, a microbiologist observes an organism that has a dry, pink colony with a surrounding halo of pink on MAC. What organism are they likely observing?** Klebsiella/Enterobacter-like organism Haemophilus influenzae Escherichia/Citrobacter-like organism Enteric pathogen

Escherichia/Citrobacter-like organism

**When examining colony size on culture plates, what organisms generally have larger colonies y comparison?** Gram-positive rods Gram-negative rods Gram-negative diplococci Gram-positive cocci

Gram-negative rods

**When examining a vaginal culture, a microbiologist observes very white colonies that are non-hemolytic on BAP but appear to have feet. What organism is likely present?** Gram-negative rods Yeast Haemophilus influenzae Gram-positive cocci

Yeast

**All of the colors below are commonly used to describe bacteria, except** buff gray white orange

orange

**Biochemical tests are based on microbial .** mitochondria phenotype characteristics plasmid number antibiodies lysogeny formation

phenotype characteristics

**Arguably the most important carbohydrate determination, screening of gram-negative rods is first performed by testing for the use of _.** glucose mannitol sucrose lactose

lactose

**When performing the O/F test two tubes are used. Why is one tube covered with mineral oil? ** To create an asaccharolytic environment To create an anaerobic (fermentative) environment To create a reductive environment To create an aerobic (oxidative) environment

To create an anaerobic (fermentative) environment

**Semi-solid medium that is helpful in differentiating gram-negative bacteria in the Enterobacteriaceae family. Used to determine motility, production of H2S, and indole production.** Urease agar SIM agar Citrate agar LIA slant

SIM agar

**Commercial identification systems fall into all of the following categories, except** enzyme-based reactions use of nitrogen and sulfur sources visual detection of bacterial growth pH-based reactions molecular assays

use of nitrogen and sulfur sources

**The identification system for gram-negative fermentative bacteria that has a series of 20 cupules attached to a plastic strip. Inside the cupules are lyophilized pH-based substrates. What is the name of this system? ** Enterotube II Microbact None of the other answers are correct API 20E ID Tri-Panel

API 20E

What result is shown for the TSI agar slant below?

Ferments glucose, lactose (or sucrose), no gas is produced, but hydrogen sulfide is produced.

**The ONPG test is used to test for** ornithine decarboxylation vs deamination delayed lactose fermenters vs nonlactose fermenters sucrose fermenters vs nonfermenters citrate utilization vs unable to utilize citrate

delayed lactose fermenters vs nonlactose fermenters

**Why is zinc added during the nitrate reduction test? ** To determine if nitrate was reduced to nitrite and then further reduced to a product like nitrogen gas To determine if nitrite is reduced completely to nitrate and the further reduced to a product like nitrogen gas To determine the presence of urease within the media To determine the presence of the cytochorome oxidase system within the bacteria

To determine if nitrate was reduced to nitrite and then further reduced to a product like nitrogen gas

**Enterics use two separate pathways for glucose metabolism within the Embden-Meyerhof pathway. Which test determine whether the bacterium uses the butylene glycol pathway for this type of metabolism?** Voges-Proskauer (VP) Methyl Red (MR) Phenylalanine deaminase (PAD) test Motility-Indole-Ornithine (MIO) test

Voges-Proskauer (VP)

The study of antibodies and their reaction with antigens that bind specifically to antibodies or T-cell receptors, in the diagnosis of infectious diesease is called

serology

Which of the following is NOT a disadvantage of using immunodiagnosis? Immunocompromised patients may have diminished responses Cross-reactive antibodies Detection of infectious agents that are difficult to culture Generally takes 10-14 days to produce an immune response

Detection of infectious agents that are difficult to culture

Which of the following is NOT an immunochemical method to detect the cause of an infection? Coagglutination method Double immunoelectrophoresis ELISA RT-PCR Latex Agglutination method

RT-PCR

Which of the following is descriptive of the part of the antigen that binds to an antibody?

epitope

A test to determine blood type may be done by mixing blood to antibodies for each possible blood type and looking for clumping as an indicator of the specific antigens present on red blood cells. This is a type of immunodiagnostic test using the ELISA procedure. t/f

false

Amplify cDNA produced from mRNA to detect expression of genes, using multiple temperatures.

Reverse transcriptase PCR

Method for identification of many microbes at the same time from mixed populations, by sequencing specific DNA regions of the microbes.

Metagenomics

Many molecules are placed on a surface at defined locations and they are used to test affinity with another molecule(s). These have been developed for genomics and proteomics studies.

Nanoarrays

Indicates differences or likenesses in nucleotide sequences after cutting the DNA into segments and determining the fragmentation pattern using electrophoresis.

Restriction Fragment Length Polymorphism

Method used to detect certain bacteria from clinical specimens by targeting rRNA.

Transcription-Mediated Amplification

Method that uses mass spectrometry for rapid identification of microbes in a clinical microbiology lab.

MALDI-TOF

Used to amplify nucleic acids, like the genome of RNA viruses, using only a single temperature.

Nucleic Acid Sequence-Based Amplification

Amplify specific, target segments of DNA using primers specific for regions flanking the sequence to be amplified. Cycles through 3 temperatures.

Polymerase Chain Reaction

Short, specific sequences of ssDNA or RNA that are labeled and used to identify one or more sequences of interest within denatured nucleic acid by hybridization and detection.

Nucleic Acid Probes

Which of the following is NOT a reason to use molecular techniques instead of traditional culturing techniques for microbe identification? Identify microbes that cannot routinely be cultures. Detect microbes that have a long incubation period. Are considered too hazardous to be grown in most labs. All of the answers are reasons to use molecular techniques

All of the answers are reasons to use molecular techniques

Match the antibiotic with the mode of action: bacterial cell wall synthesis

glycoproteins penicillin

Match the antibiotic with the mode of action: folate synthesis

sulfonamides trimethoprim

Match the antibiotic with the mode of action: DNA replication

quinolones

Match the antibiotic with the mode of action: RNA transcription

rifampin

Match the antibiotic with the mode of action: mRNA translation by targeting the 30S subunit of the ribosome

tetracyclines aminoglycosides

Match the antibiotic with the mode of action: mRNA translation targeting the 50S subunit of ribosome

macrolides chloramphenicol

Efflux pumps

function as transporter proteins involved in the removal of toxic substances from the interior of the cell to the external environment

This is one of the first resistance mechanisms identified and is a strategy that bacteria use successfully to survive the action of many classes of antibiotics.

Acquisition of inactivating enzymes

A patient undergoes a colon resection. Because of the amount of bacteria present in the colon, the physician put the patient on broad-spectrum antibiotics after surgery. The patient develops a fever 2 days after surgery. He developed an infection with vancomycin-resistant enterococci (VRE). True or False: There is currently no other antibacterial agent available to treat this patient. t/f

false

When should antimicrobial susceptibility testing be performed on a bacterial isolate from a clinical specimen? a) When the isolate is determined to be a probable cause of the patient's infection b) When the susceptibility of the isolate to particular antimicrobial agents cannot be reliably predicted without testing c) Both a and b

c) Both a and b

The most widely used method of inoculum standardization is the

McFarland turbidity standards

What type of broth is most commonly recommended in determining the MIC of an antibiotic against a particular pathogen?

Mueller-Hinton

What is a breakpoint panel?

An MIC panel with only one or a few concentrations of each drug

On a breakpoint panel, when two concentrations are tested and no growth is present in either well, the isolate is:

susceptible

A zone of inhibition is:

the area around the antibiotic disk where the bacteria cannot grow

Oxacillin-resistant Staphylococcus aureus is also called _____-resistant S. aureus

methicillin

The most widely used supplementary quality control measure for antimicrobial susceptibility testing is

Use of antibiograms to verify results generated on patient isolates

The minimal inhibitory concentration (MIC) is

the lowest antibiotic concentration to inhibit the growth of an organism

A drug will generally inhibit multiplication of the bacteria so that the patient's immune defense mechanisms are no longer overwhelmed when

the drug concentration exceeds the MIC for the microbe