Microbiology Test II Quiz 2

hold the plate up to the light, and observe the plate with the light coming from behind

To read the hemolytic reaction accurately on a blood agar plate, the technologist must

Selective and differential

In which category of media would MacConkey agar best fit

sufficiently large numbers of a bacterium that can be observable with the unaided eye

A bacterial colony can be described as

Capnophiles

Increased concentrations of carbon dioxide (CO₂) (5% to 10%) and approximately 15% oxygen (O₂) produce an environmental condition that best suits which type of organism

No discrepancy is present. The correct results are obtained

An oxidase test was performed on two organisms for quality control purposes. Pseudomonas aeruginosa and Stenotrophomonas maltophilia tested positive and negative, respectively. Which of the following statements explains this discrepancy

the ability of two nucleic acid strands that have complementary base sequences to bond specifically with each other and form a double-stranded molecule

Hybridization methods are based on

Increase the salt concentration in the hybridization buffer

While developing a new hybridization-based molecular test for Cryptosporidium, a protozoan parasite that causes diarrheal illness, a laboratory technician examines the hybridization ability with a closely related, but nontarget, protozoan and also gets a positive test result. In order to improve the stringency of the hybridization reaction for detection of Cryptosporidium only, the technician can do which of the following

72°C

The enzyme that is commonly used for primer extensions in the PCR method works best at what temperature

Ethidium bromide

The optimal way to detect PCR amplicons is to use which stain

5'-GAATCGCAT-3'

Identify the appropriate DNA homolog, or complementary sequence, that could be used as a probe for in situ hybridization to the following target RNA: 5'-AUGCGAUUC-3'

are produced by the offspring of a single hybrid cell

Monoclonal antibodies are those that

Treponema pallidum

A positive test was observed on a serum sample that resulted in the formation of a fine precipitate in a flocculation assay on a reaction card. The most likely organism serologically identified is

the type of particle used to carry the antibody

The difference between latex agglutination and hemagglutination is

attaching to the surface of pathogens and contributing to their destruction by the lytic action of complement

Complement-fixing antibodies are those that function by

double immunodiffusion

The precipitin test that involves antigen and antibody diffusing toward each other, producing a visible precipitin band at the point at which they meet, is referred to as

TOTAL-FIX

Which of the following is currently the only fixative available that does not contain formalin, polyvinyl alcohol (PVA), or mercury

Starch granules

Irregularly-shaped objects of various sizes are seen in an iodine-stained wet mount prepared from a freshly passed stool specimen.  These objects are gray to black and some are found inside parenchymal cells.  What are these gray to black objects most likely to be

Macrophages

Pseudoparasites such as  ?  can be seen in stained stool smears.   They have a single nucleus and sometimes ingest red blood cells.  They can be differentiated from true parasites because they do not have a cyst wall, glycogen vacuoles, nor chromatin bodies.  The nuclear to cytoplasmic ratio is quite high.  Sometimes degenerate forms with darkly staining inclusions but no visible nucleus are seen

is designed to allow the detection of protozoan cysts, coccidian oocysts, microsporidial spores, and helminth eggs and larvae

The concentration protocol of the ova and parasite (O&P) examination

Football-shaped eggs with one flattened side

A 4-year-old boy who is in day care 3 days per week is irritable and scratching the area around his anus. What morphologic characteristics would most likely be observed on microscopic examination of the appropriate specimen

Isolator system

Blood cultures are collected from a 36-year-old patient suspected of having a disseminated fungal infection. History reveals that she was exposed to bird droppings and may have inhaled the conidia. What is the best blood culture system to use to ensure optimal recovery of this pathogen

Rhizopus

A septate hyphae is microscopically observed using lactophenol cotton blue. Which organism can be ruled out as the cause of infection on the basis of this information

chitin

The cell wall of plants is composed of cellulose but the cell wall of fungi is composed of

furrows radiate out from the center

If a fungal colony is described as rugose, then it means that the colony

Calcofluor white

Which stain requires the use of a fluorescent microscope

HSV

Arbovirus

Adenovirus

HBV

Match the virus with the appropriate specimen

Vesicular

Cerebrospinal fluid (CSF) antibody

Respiratory

Blood

HSV

The enzyme-linked virus-inducible system (ELVIS) uses a cloned β-galactosidase gene that is expressed only when cells are infected with what virus

Shell vial

The cytomegalovirus (CMV) produces cytopathic effects (CPE) in diploid fibroblast cells in an average of 7 days. The results are available within 16 hours using which type of assay

all of the responses are correct

Nucleic acid amplification tests have replaced cell culture for the identification and diagnosis of viruses due to the fact that

Attachment

Penetration

Uncoating

Synthesis

Assembly

Release

List these six steps of viral replication in order of appearance.

a. Assembly
b. Uncoating
c. Attachment
d. Release
e. Synthesis
f. Penetration

the relative amount of organism present in the original specimen

When streaking for isolation and utilizing semi-quantitative methods, the numbers of colonial growth in successive quadrants correlates directly with

Hektoen enteric agar

Which medium can be described as containing bile salts and dyes (e.g., bromothymol blue and acid fuchsin) to slow selectively the growth of most nonpathogenic gram-negative bacilli found in the gastrointestinal tract and allow Salmonella spp. and Shigella spp. to grow

Supportive

Which category of media can be described as containing nutrients that support the growth of the most nonfastidious organisms without giving any particular organism a growth advantage

lipopolysaccharides

Which of the following cell wall components contains the toxic component of gram negative cell walls (lipid A)

Labeling of probe, heating sample to obtain single-stranded target nucleic acid, hybridization of target to probe, detection of hybridization

Place the basic steps involved in a molecular hybridization assay in sequence from first to last in the order in which they would be performed

They do not require selection of suspected pathogens prior to testing

What key advantage do emerging technologies, such as MALDI-TOF and next generation sequencing, have over conventional hybridization and amplification techniques

Amplification (PCR)

Complementary nucleic acid hybridization, which is coupled with nucleic acid replication and applied repeatedly through numerous cycles, is based on which of the following methods

Phenotypic methods examine the growth behavior of a microorganism and the proteins, enzymes, or toxins produced, while molecular methods examine the genetic makeup

What differentiates diagnostic techniques that employ phenotypic (culture-based) methods from those that employ molecular methods

cerebrospinal fluid (CSF).

A positive latex agglutination test was observed in a sample containing Cryptococcus spp. The specimen of choice to identify this pathogen is

serology

The study of the diagnosis of disease by measuring antibody levels in serum or other body fluids is called

increased sensitivity

The primary advantage for the implementation of a multiplex immunoassay is

Neobalantidium coli

Which of the following intestinal parasites is found in humans and in pigs

sandfly

Some strains of leishmaniae have reservoir hosts, including dogs and wild rodents. Transmission is via the bite of a

serologic means

The parasite T. gondii is acquired via the ingestion of infected oocysts from cat feces. A diagnosis is primarily made through

Pollen grains

Artifacts found in a stool specimen that can be confused with ova or cysts are

S. schenckii

A 28-year-old woman was gardening when a rose thorn pricked her finger, which later became infected. A sample is taken of the exudate and sent to the microbiology laboratory. Small, round, cigar-shaped structures are microscopically observed. She is most likely infected with which type of fungi

ascospores

The acid fast stain can be used to demonstrate which of the following types of sexual spores

The ingredients in the cycloheximide agar most likely inhibited the growth of the organism

A 29-year-old patient with acquired immunodeficiency syndrome (AIDS) is suspected of having a C. neoformans infection in the cerebrospinal fluid (CSF). A CSF specimen is collected and set up on cycloheximide agar. In addition, an India ink stain is set up. The India ink stain reveals encapsulated yeast; however, 3 weeks later, the cycloheximide agar is negative. Which one of the following statements explains this discrepancy

Aspergillus

A 59-year-old patient with cancer who was receiving high doses of chemotherapy developed a secondary lung infection that was identified as a fungus. The organism disseminated, which ultimately was fatal to the patient. The organism isolated from sputum exhibited septate hyphae that were dichotomous. The organism is most likely which of the following

cytopathology

Virus detection by examining stained cells (tissue sections or cell cultures) using brightfield microscopy is called

virus neutralization  

In the _____________ test a suspension of the test virus and patient serum are mixed and incubated.  If antibody directed against the virus is present in the patient’s serum it will destroy the ability of the virus to infect cells.  This is tested by adding the mixture (virus suspension and patient serum) to a cell culture and looking for cytopathic effect.  If infectivity of the test virus is lost due to specific antibody in the serum of the patient, there will be no cytopathic effect in the cell culture.  If the patient does not have the viral infection there is no antibody to prevent the virus from infecting the cells of the cell culture and cytopathic effect will be seen

Papilloma

Some viruses have the ability to stimulate uncontrolled growth of the host cells, resulting in cancer. Which virus has oncogenic properties

rabies virus

If Negri bodies are identified in brain tissue through cytologic means, then the virus is identified as a(n)

MacConkey agar

Which medium can be described as containing crystal violet dye to inhibit the growth of gram-positive bacteria and fungi and allows many types of gram-negative bacilli to grow

Selective

Which category of media can be described as containing one or more agents that are inhibitory to all organisms except those being sought

reincubate for additional time period if no growth is evident

Media function testing should include all of the following except

polysaccharide

The chemical composition of bacterial capsules is most often

Endonuclease

Which enzyme recognizes a specific nucleotide sequence (~4 to 8 nucleotides in length) and catalyzes the digestion of the nucleic acid at that site, causing a break in the DNA strand

Size

Gel electrophoresis is used to separate nucleic acid amplicons based upon what physical property

increase; two

For most pathogens to be diagnostic of current infection, there must be a(n) _____ in the patient’s antibody titer of _____ doubling dilutions

Prozone effect

A serial dilution is completed on a patient’s sera to determine an antibody titer. The dilution is a doubling dilution as follows: 1:2, 1:4, 1:8, 1:16, 1:32, 1:64 and 1:128. There is no agglutination in the first three dilutions and the last dilution. What is the reason for the absence of dilution in the first three dilutions in this reaction

Western blot assay

This assay uses electrophoresis, followed by the transfer of proteins to a solid support matrix, the proteins are then identified using specific antibodies conjugated to an enzyme substrate for identification

the type of particle that carries the antigen

The difference between direct latex agglutination and indirect latex agglutination is

Definitive hosts

Hosts which harbor the sexually mature (adult) stage of a parasite or where sexual reproduction occurs are called

sputum

The specimen of choice to collect in suspected cases of Paragonimus infection is

Intermediate hosts

Humans and animals which harbor the developmental stages of a parasite (larval forms) or hosts in which asexual reproduction alone occurs are called

Arthroconidia

Microscopically, this fungus appears barrel shaped with thick walls, which best describes which type of conidia

Potassium hydroxide (KOH) mount

Which of the following preparations allows fungal elements to be seen in clinical specimens such as skin scrapings, nail clippings, and sputa because it digests keratin (the protein found in skin, hair, and nails)?  Chitin in the cell wall of fungi resists degradation while, RBCs and WBCs are destroyed

The medium is most likely expired

Urea agar is set up for quality control purposes using two Trichophyton spp.—T. mentagrophytes and T. rubrum. After the appropriate amount of incubation, both organisms are negative. Which one of the following statements explains this discrepancy

stool

A 2-year-old girl is suspected of having a rotavirus infection. The specimen of choice to collect to identify the agent is

Respiratory syncytial virus (RSV)

The most used EIA for antigen detection that uses a solid phase and membrane is used for detecting which virus

Monkey Kidney Cells

Fibroblast Cells

Hep-2 culture cells

Match the cells with the appropriate cell line.

Group of answer choices

Primary cell line

Diploid cell line

Continuous cell line

0 to 4

If not inoculated immediately, viral specimens should be stored in viral transport media for up to 48 hours.  What is the correct storage temperature

eclipse

The period of intracellular viral synthesis where there is no visible evidence of viral replication is during which phase of the replication cycle

Brain-heart infusion (BHI)

Which medium can be described as a nutritionally rich medium used to grow various microorganisms, either as a broth or as an agar, with or without added blood

time required for a bacterial population to double

Generation time can be defined as the

35°C to 37°C

The most medically important bacteria sought in the medical laboratory are cultivated using incubators with temperatures maintained in what range

Quantitative PCR

Analysis of the number of target molecules in the original clinical specimen can be determined using which of the following molecular techniques

Nucleic acid purification

Which of the following steps are crucial for the success of a nucleic acid amplification test, such as PCR

originating from an organism of known identity with a known sequence

The probe in the hybridization assay can be described as

direct fluorescent antibody test

A test procedure that applies a specific fluorescent dye-antibody complex to a slide to which the patient specimen has been applied is referred to as a(n)

react with many different antigens of one specific organism

Polyclonal antibodies are those that

Detection of rickettsial infections using strains of Proteus is not as specific as other serologic tests; therefore the infections should be retested with a newer method

A patient was suspected of having a rickettsial infection after hiking in the Rocky Mountains. A Weil-Felix test was performed, which resulted in no agglutination observed. Which one of the following statements explains this discrepancy

Giardia duodenalis

The Entero-Test Capsule technique involves the collection of duodenal contents to examine the presence of which of the following parasites

Acanthamoeba spp

A 17-year-old male with a severe eye infection admits that he does not clean his contact lenses as often as he should. His eye infection is most likely the result of which parasite

Reservoir hosts

Animals which harbor the same parasitic species as man and which serve as additional sources of infection (making control of parasitic diseases more difficult) are called

Direct fluorescent antibody (DFA)

The PARA-TECT Cryptosporidium/Giardia test kit uses which of the following formats for detection

superficial

A 16-year-old male teenager is diagnosed with a fungal infection of his foot, which he acquired at the gym. This infection would most likely be classified as a(n) _______ mycosis

Mycosel agar

Which fungal media is ideal for the recovery of organisms such as Microsporum and Trichophyton

Inhalation of spores

Fungal infections are generally acquired via which route

uncoating

The period, during viral replication where the capsid is removed by host enzymes is called

Reverse transcriptase polymerase chain reaction (RT-PCR)

Which assay is the current recommended method of detection in most laboratories for influenza A and B viruses

opaque

Colonies that appear white and shinny are also considered

Selective and Differential medium

MacConkey is a good example of a/an

MacConkey and Columbia with colistin and nalidixic acid (CNA) agars

A mixture of organisms (gram positive and gram negative) is seen on the gram stain of material aspirated from a peritoneal abscess.  Which inhibitory media should be included so both types of organisms can be isolated

Clostridium or Bacillus species

Large, spore forming, gram positive rods seen on direct microscopic examination of material from a wound exudate could be indicative of

In situ

Which type of hybridization method would be the optimal choice to use to detect a lesion infected with a particular virus

3'-CACGGA-5'

Predict which of the following DNA oligonucleotide probes would have the highest melting temperature (Tm) when hybridizing to the target sequence 5'-GTGCCTGAATGCAATGTCA-3’

Copying of DNA to RNA

Transcription is the

The risk is low; a fourfold rise in titer is not present

A pregnant woman had contact with her nephew who was just diagnosed with a rubella infection. Acute and convalescent samples were taken, which resulted in an acute titer of 1:16 and a convalescent titer of 1:32. Which one of the following comments explains the risk to the fetus