Module 5: Chapter 15 Flashcards
1
Q
tests that can be performed at the bedside, meaning samples do not have to be sent out and patient care can continue without delay
A
point-of-care testing/diagnosis
2
Q
scans often used to diagnose peritonsillar abscesses
A
computerized tomography (CT) scans
3
Q
scan used to find areas of deep tissue infection
A
magnetic resonance imaging (MRI) scan
position emission tomography (PET) scan
4
Q
refers to the traits that an organism is expressing in the present
A
phenotype
5
Q
method of microbial identification:
observation of microbe’s microscopic and macroscopic morphology, physiology, and biochemical properties; involves examining their appearance and behavior ( behavior = enzymatic activities they carry out, what kind of physical conditions they thrive in, what antibiotics it is susceptible to, and the chemical composition of its walls and/or membrane)
A
phenotypic methods
6
Q
method of microbial identification:
the nature of the antibody response is exploited for diagnostic purposes when a patient sample is tested for the presence of specific antibodies to a suspected pathogen (antigen)
analysis of microbe using antibodies, or of patients’ antibodies using prepackaged antigens
alternatively, microbial antigens in the patient’s tissues can be tested with antibodies “off the shelf” (these methods can be easier than trying to isolate the microbes itself.
A
immunologic methods
7
Q
methods of microbial identification:
analysis of microbe’s DNA or RNA
ie. numerous viable nonculturable (VNC) microbes are currently being identified in this manner through studies such as the Human Microbiome Project
A
genotypic methods
8
Q
primary advantages of genotypic methods over phenotypic methods
A
culturing of the microorganisms is not always necessary
genotypic methods are increasingly automated, producing rapid results that are often more precise than with phenotypic methods
9
Q
15.1 outcome
list the three major categories of microbial identification and a one sentence description for each
A
- Phenotypic methods: examining the appearance and behavior (enzymatic activities, physical conditions it thrives in, antibiotics its susceptible to, chemical comp of walls/membranes)
- Immunologic methods: examining the antibodies present in a patient’s sample, to see if the antibodies link to the suspected antigens; antigens in the patients tissues can be tested with antibodies “off the shelf”
- Genotypic methods: examining a microbes genetic material (RNA or DNA
10
Q
15.2 First Steps: Specimen Collection
A
11
Q
the success of identification and treatment depends on how specimens are:
A
collected, handles, stored, and cultured
12
Q
in specimen collection it is important that general _______ procedures be used, including sterile sample containers and other tools to prevent contamination from the environment or patient.
A
aseptic
13
Q
throat and nasopharyngeal swabs should not touch the cheeks, tongue, or _____.
A
saliva (saliva contains millions of bacteria per milliliter, most of which is normal biota)
14
Q
mucus secretion that coats the lower resp surfaced, especially the lungs; is discharged by coughing or taken by a thin tube called a catheter to avoid contamination with saliva
A
sputum
15
Q
saliva samples may be needed for dental diagnosis and are obtained how?
A
having the pt spit or drool into a container
16
Q
the mucous lining of the urethra, vagina, or cervix can be sampled with a swab or _______
A
applicator
17
Q
depending on the nature of a skin lesion, skin can be swabbed or scaped with a scalpel to expose deeper layers; wounds are sampled either by _______ or by using a __________
A
swabbing or a punch biopsy tool
18
Q
fluids such as blood, cerebrospinal fluid, and tissue fluids must be taken by _______ _______ _______
; antisepsis of the puncture site is extremely important in these cases
A
sterile needle aspiration
19
Q
name some additional sources of specimen besides urine, blood, CSF, mucous secretions, and sputum
A
eye, ear canal, synovial fluid (joint fluid), nasal cavity (all by swab), and diseased tissue that has been surgically removed (biopsied)
20
Q
nonsterile samples such as urine, feces, and sputum, are especially prone to deterioration at
A
room temperature
21
Q
nonnutritive maintenance media
A
a media used to maintain specimens in stable conditions for several hours, but will but grow them
22
Q
before collecting a specimen, what should your analyze a patient for?
A
signs of microbial infection such as fever, wound exudate, mucus production, abnormal lesions
23
Q
the time required for testing _______
ie. a few minutes for rapid strep testing to several weeks for tuberculosis testing
A
varies
24
Q
- 2 outcomes
- identify factors that may affect the identification of an infectious agent from a sample
- compare the types of tests performed on microbial isolates versus those performed on patients themselves
A
1.
- improper collection technique
- collection, transport, storage, labeling
- Microbes: analysis involves
- Direct testing using microscope, immunologic or genetic methods that provide clues to identify the microbes.
- Cultivation, isolation, and identification of pathogens using a wide variety of general and specific tests.
Patients: tests on patient serum provide indirect evidence for specific pathogens though analysis of the antibody response. Skin testing can be used or some pathogens can be identified solely on the patient’s signs and symptoms
25
15.3 Phenotypic Methods
26
most used stains for bacterial identification
Gram stain and acid-fast stain
but as useful as these stains are they can identify only a few organisms on their own
27
direct microscopic observation of a fresh or stained specimen is one of the most ______ methods of determining presumptive and sometimes confirmatory microbial characteristics
rapid
28
in cases where the suspected pathogen is present in small amounts or is easily overgrown by normal biota, the specimen can be initially enriched with ____________ media.
specialized
29
nonsterile specimens containing a diversity of bacterial species, such as urine and feces, are cultured on _______ media to encourage the growth of only the suspected pathogen
selective
30
specimens are often inoculated into _________ media to identify definitive characteristics, such as reactions in blood (blood agar) and fermentation patters (mannitol salt and MacConkey agar)
differential media
31
dichotomous key
a graphic method that is essentially a flowchart leading to the identification of specimens
"di" refers to the fact that at each branch of the flowchart there are two (di) possible outcomes
32
a straightforward way to phenotypically identify specimens is to combine the results of tests such as gram staining (neg or pos?), growth on different media, and simple enzymatic tests -----> this can form the starting point for what
dichotomous key
33
cocci --->
gram + or gram - --->
gram + = Catalase + (irregular clusters, tetrads) or catalase - (pairs, chain arrangement) --->
catalase - = Streptococcus
catalase + = strictly aerobic or facultative anaerobic
strictly aerobic = micrococcus
facultative anaerobic = Staphylococcus/Planococcus
example of gram + dichotomous key
34
what technique in this chapter do most home pregnancy test kits utilize?
the lateral-flow test, which is an immunochromatographic method
35
Biochemical testing:
the physiological reactions of bacteria to nutrients and other substrates provide excellent evidence of the types of ______ systems present in a particular species;
knowing which ____ an isolate has can often leas to its identity
enzyme
| enzymes
36
many biochemical testing are based on ________-mediated metabolic reactions that are visualized by a color change
enzyme
37
in enzyme-mediated biochemical testing the microbe is cultured in a medium with a special substrate and then tested for a particular end product.
microbial expression of the enzyme is made visible by a colored dye, no coloration means it ________ the enzyme for utilizing the substrate in that particular way
lacks
38
Mycobacterial Growth Indicator Tube (MGIT)
a type of phenotypic test used to detect the growth of slow-growing Mycobacterium tuberculosis
---> this system monitors oxygen levels in a tube that has been inoculated with a patient specimen (blood, sputum), tube contains medium that encourages growth of the tuberculosis bacterium; ***there is a silicon chip at the bottom of the tube that is impregnated with a fluorescent substance that is sensitive to oxygen
--> when first inoculated, there will be a lot of free oxygen in the medium because even if the bacteria are present, there will not be many of them
BUT, if the bacteria grow, they begin using the oxygen, and the decreased levels of O2 allow the silicon compound to fluoresce
39
antimicrobial susceptibility testing and phenotypic methods
most of the automated phenotypic systems incorporate a panel of commonly used antimicrobials for the particular infection site; and simultaneously test susceptibility while IDENTIFYING the pathogen;
*** commonly completed using an adaptation of the tube-dilation method (chapter 12)
--> these tests themselves can identify some species like Streptococcus, Clostridium, and Pseudomonas
40
miscellaneous tests:
Phage Typing
relies on bacteriophages (viruses that attack bacteria in a very species-specific and strain-specific way
---> useful in identifying some bacteria, primarily Salmonella, and is often used for tracing bacterial strains in epidemics
- --> phage typing involves: inoculating a lawn of bacterial species onto agar, mapping it off into blocks, and applying a different PHAGE to each sectioned area of growth
so: CLEARED AREAS corresponding to lysed cells indicate sensitivity to the PHAGE, and a bacterial identification may be determined from this pattern
41
__________ __________ are needed to cultivate bacteria such as Mycobacterium leprae and significant quantities of Treponema pallidum;
whereas __________ _________ and cell cultures can be used to grow host cell-dependent rickettsias, chlamydias, and viruses
susceptible animals
avian embryos
42
what are some clinically significant features of cultures?
- the number of microbes present ie. a few colonies of E. coli in a urine specimen can simply indicate normal biota, several hundred colonies can indicate active infection
- the presence of a single colony of a true pathogen, such as Mycobacterium tuberculosis in a sputum culture or an opportunist in sterile sites such as in CSF or blood, is highly suggestive of its role in disease
43
the repeated isolation of a relatively pure culture of any microorganism can mean it is an agent of _______.
disease
44
two major drawbacks of phenotypic methods
(1) when the microbe has to be cultured, it takes a minimum of 18 to 24 hours, and often longer
(2) we are learning that many infectious conditions may be caused by nonculturable organisms, leaving open the possibility that the organism that we do culture is simply a bystander
45
phenotypic Dx methods summary
Direct Examination: microscopy of patient specimens, usually after staining (does not require cultivation)
Biochemical Testing: growth of microbe in media that detects the presence of microbe's enzymes, creating a metabolic "fingerprint" (requires cultivation)
Susceptibility Testing: in some cases a particular patter or antimicrobial susceptibilities can lead to the identity of a microbe (requires cultivation)
Miscellaneous: Phage Typing, Animal inoculation, cell culture growth (requires cultivation)
Selective/Differential Growth: use of specialized media that reveal identifying characteristics such as colony appearance, motility, and gas requirements (requires cultivation)
46
15. 3 Outcomes
1. List at least three tests that fall in the direct identification category.
2. Explain the main principle behind biochemical testing, and identify an example of such tests.
3. Discuss two major drawbacks of phenotypic testing methods that require culturing the pathogen
1.
- Direct observation of fresh of stained specimen
- Biochemical testing
- Isolation media and morphological testing (when pathogen numbers are small, pathogen can be isolated and grown with enriched media)
2. Physical reactions of bacteria to nutrients and other substrates provides excellent evidence of the types of enzyme systems present in a particular species. Most of these tests are based on enzymatic reactions visible by a color change.
ie. Production of acid and/or gas=carbohydrate fermentation
Hydrolysis of gelatin, starch, and fats
Actions of enzymes: catalase, oxidase, coagulose, lipase
Various by-products of metabolism
3. Takes a longer time to get results, possibility of errors in storage, transportation, and culturing
47
15.4 Immunologic Methods
48
branch of immunology that traditionally deals with in vitro diagnostic testing of serum
serology
49
serological testing is based on the principle that
antibodies have extreme specificity for antigens, so when a particular antigen is exposed to its specific antibody, it will fit like a hand in a glove
50
what other fluids are tested in serology now a days?
not just sera, we also test urine, CSF, whole tissues, and saliva.
51
immunologic Dx methods
Agglutination/Precipitation: A- antibody-mediated clumping of whole cells
P- smaller complexes of antibody-antigen
Immuno-chromatography: most common for is a lateral-flow system, supplied in prepackaged cartridges that produce a colored stripe
Western Blot: electrophoresis separates proteins (either antigens or antibodies) and then labeled antibodies or antigens are used for detection
Fluorescent Antibodies:
Direct- unknown specimen is exposed to known fluorescent Ab
Indirect- patient's antibody (its Fc portion) probed with fluorescent Ab
ELISA: sandwiching technique using Ag, Ab, and a secondary Ab to produce a color change
In vivo Tests: antigen introduced into a patient to elicit a reaction, such as a TB skin test
52
Agglutination and Precipitation + their differences
differences are in size, solubility, and location of the antigen
A- antigens are whole cells or organisms such as RBCs, bacteria, or viruses displaying whole surface antigens
-> easily seen because it forms visible clumps of cells, such as in the Weil-Felix reaction used in dx-ing rickettsial infections
P- (smaller clumps) the antigen is examined is a soluble molecule
---> in both reactions, when antigen and antibody concentrations are optimal, one antigen is interlinked by several antibodies to form insoluble aggregates that settle out in solution
53
Agglutination is also used to determine blood ________.
compatibility
54
immunochromatography
"lateral-flow test"
| can be found in drugstore pregnancy tests, and rapid strep tests in the doctor's office
55
an antigen-antibody reaction in liquid is read as a ________, or the concentration of antibodies in the sample
titer
56
define titer
; it is determined by serially diluting patient serum into test tubes or wells of a microtiter plate, all of which contain equal amounts of bacterial cells (antigens)
defined as the highest dilution of serum that still produces agglutination
-> in general, the more serum a sample can be diluted and still react with antigen, the greater the concentration of antibodies, and thus its titer
57
antibody titers are often used to diagnose autoimmune disorders such as _____ and _____, and also to determine past exposure to certain diseases such as rubella.
rheumatoid arthritis, and lupus
58
antigen-antibody technique for identifying, classifying, and subgrouping certain bacteria into categories called serotypes
- --> this method of immunologic dx employs antisera against cell antigens such as the capsule, flagellum, and cell wall.
* widely used in identifying Salmonella species and strains, and is the basis for differentiating the numerous pneumococcal and streptococcal serotypes
serotyping
59
immunologic methods widely used in identifying Salmonella species
serotyping
60
involves the separating of proteins by electrophoresis, and then using antibodies to detect the proteins
1. A sample of proteins is obtained from cells after lysing them is separated via electrical charge within a gel = the proteins embedded in the gel are transferred and immobilized to a special filter
2. The filter is incubated with antibody solutions, some of which have been labeled with radioactive, fluorescent, or luminescent molecules
3. After incubation, sites of specific antigen-antibody binding will soon appear as a pattern of bands that can be compared with known pos and neg controls
this is a HIGHLY specific and sensitive way to identify or verify the presence of microbial-specific antigens or antibodies in a patient sample
Western Blot Test
61
fundamental tool in testing is a fluorescent antibody, a monoclonal antibody labeled by a fluorescent dye
Direct testing- an unknown specimen or antigen is fixed to a slide and exposed to FAb solution of known composition- if antibody-antigen complexes form, they will remain bound to the sample and will be visualized by fluorescent microscopy = positive result
valuable in identifying causative agents of syphilis, gonorrhea, meningitis, etc.
Indirect testing- FAbs used in this testing recognize the Fc region of Ab's in patient sera, a known antigen (ie. bacterial cells) is added to the test serum, and binding of the fluorescent antibody is visualized through fluorescence microscopy = fluorescing aggregates or cells indicate that FAbs have complexed with the microbe specific antibodies in the test serum
frequently used to dx syphilis and various viral infections
Immunofluorescence Testing
62
"sandwich technique"
uses an enzyme-linked indicator antibody to visualize antigen-antibody reactions; this technique also relies on solid support such as a plastic microtiter plate that can adsorb (attract on its surface) the reactants
indirect: known ANTIGEN is adsorbed to the surface of a well and mixed with unknown antibody; complex forms, and indicator Ab will bind and subsequent development will produce a color change = pos result
common test for HIV, Hep A and C, and Helicobacter, and rickettsial species
direct: sandwich test; a known ANTIBODY is adsorbed to bottom of well and incubated with an unknown antigen; if any antibody-antigen complex forms, it will attract the indicator antibody and color will develop in these walls = pos result
Enzyme-Linked Immunosorbent Assay (ELISA)
63
A western blot may be needed to confirm what other type of test because of possible false positives?
ELISA indirect testing
64
employ principles similar to serological tests, except in this testing an antigen is introduced into a patient to elicit some sort of visible reaction.
ie. TB skin test where a small amount of purified protein derivative (PPD) from Mycobacterium tuberculosis is injected into the skin
In vivo testing
65
the property ff a test to focus on only a certain antibody or antigen and not to react with unrelated or distantly related ones;
ie. a test with high ________, will have a low false-POSITIVE rate.
specificity
66
the most effective tests have a high degree of ________ and _______
specificity and sensitivity
67
refers to the detection of minute quantities of antibodies or antigens in a specimen
ie. a test with high _________ will have a low false-NEGATIVE rate
sensitivity
68
15. 4 Outcomes
1. Define the term serology and explain the immunologic principle behind serological tests
2. Identify two immunologic diagnostic techniques that rely on a secondary antibody, and explain how they work
1. branch of immunology that traditionally deals with in vitro diagnostic testing of serum; based on the principle that antibodies have extreme specificity for antigens, so when a particular antigen is exposed to its specific antibody, it will fit like hand and glove
2.
immunofluorescence testing: FAbs (fluorescent antibodies) recognize the Fc region of antibodies in patient sera. known antigen (i.e. bacterial cells) is added to the test serum, and binding of the fluorescent antibody is visualized through microscopy
enzyme-linked immunosorbent assay (ELISA): known antigen is adsorbed to well, serum samples with unknown antibodies applied, well is rinsed to remove unbound antibodies, indicator antibody outfitted with an enzyme attaches to Fc portion of any antibody, well rinsed to remove unbound indicator antibody (a colorless substrate for enzyme added), and enzymes linked to indicator Ab hydrolyze the substrate, which releases a dye. wells that develop color are (+) for the antibody
69
15.5 Genotypic Methods
70
the sequence of nitrogenous bases within DNA or RNA is
unique to every microorganism ---> this is why genotypic methods have become a mainstay of microbial identification
71
genotypic test useful for outbreak investigations
Pulsed-field gel electrophoresis
72
test that results in the production of numerous identical copies of DNA or RNA molecules within hours; this method can amplify even minute quantities of nucleic acids present in a sample which greatly improved the sensitivity of these tests
can be performed on genetic material of bacteria, viruses, protozoa, and fungi
Polymerase Chain Reaction (PCR)
73
uses fluorescent labeling during the amplification procedure and the level of fluorescence is measured in real time as the reaction is running; is fully automated and is faster than traditional PCR because analysis of the DNA after the reaction is finished is not necessary
these tests often assess the antimicrobial susceptibilities at the same time they are identifying the organism
Real-Time PCR "qPCR"
74
Reverse-transcriptase PCR (RT-PCR)
involves the creation of DNA out of RNA (reversed, as usually RNA comes from DNA)
75
type of diagnostic PCR that contains primers for multiple organisms instead of just one single primer; as with biochemical panels, this test will contain primers for multiple organisms in the differential diagnosis for the patient's symptoms
---> most often this test is also real-time PCR
*tests multiple organisms not just one
Multiplex PCR
76
amplification method that, unlike PCR, does not require temperature changes; uses two enzymes, reverse transcriptase (to make DNA) and polymerase (to transcribe RNA)
Transcription-Mediated Amplification
77
technique that makes it possible to identify microbes by analyzing segments of its genetic material; this requires small fragments of single-stranded RNA or DNA called PROBES that are known to be complementary to the specific sequences of nucleic acid isolated from a particular microbe
---> base pairing of the known probe to the nucleic acid can be observed, providing evidence of the microbe's identity
*probes are typically fluorescently labeled or attached to an enzyme that triggers colorimetric change when __________ occurs
hybridization
78
COVID-19 at home tests that detect viral RNA, are what time of PCR test?
RT-PCR
| Reverse-transcriptase polymerase chain reaction test
79
Hybridization
| Fluorescence in situ hybridization (FISH) technique
involves the application of fluorescently labeled probes to intact cells within a patient specimen or an environmental sample
*microscopic analysis or automated processed are used to locate "glowing" cells and conclude the identity of the microbe
***used to identify the microbial components of a BIOFILM
---> often used to confirm diagnosis or identify a specific microbe; FISH is deceasing in use as PCR tests become more convenient and accurate but FISH is still used in cancer diagnosis especially in personalized medicine where a patient's DNA is examined for particular characteristics that can make a drug a better choice for them
80
_________ designed for infectious disease diagnosis are "chips" (absorbent plates) that contain gene sequences from potentially thousands of different possible infectious agents, selected based on the syndrome being investigated (such as resp infection or meningitis symptoms)
**matching sequences hybridize to the chip, and the label (most often fluorescence) is detected by a computer program which identifies the isolate or isolates
---> could include genes for fungal, bacterial, or viral all in one single test
Microarrays
81
particularly useful for rapid analysis of outbreaks and drug resistant organisms; this method is generally low cost and low time of completion
a single genome can be scanned and analyzed multiple times in a process called "deep-sequencing", which minimizes error
Whole-Genome Sequencing
82
in chapter 8, ___________ was described as a method for analyzing short segments of DNA within a sample
fingerprinting
83
similar to fingerprinting, but instead involves the separation of DNA fragments that are too large for conventional gel electrophoresis methods;
this is accomplished by slowly adding alternating voltage levels to the gel from three different directions, allowing even similarly sized DNA fragments to fully separate
---> because the DNA is subjected to restriction enzymes, single changes in the DNA sequence (from mutations) will result in fragments of different sizes
**often used in acute outbreaks of foodborne illness and other infections
Pulsed-Field Gel Electrophoresis: Microbial Fingerprints
84
15. 5 Outcomes
1. Explain why amplification techniques are useful for infectious disease dx
2. name two techniques that employ hybridization
3. explain how whole-genome sequencing can be used for diagnosis
4. identify the situations in which pulsed-field gel electrophoresis is most useful
1. because amplified amounts of a pathogen can lead to more data for investigation and high specificity + sensitivity
2. name two techniques that employ hybridization
- FISH (fluorescent in situ hybridization)
- Microarrays (matching sequences hybridize to the chip, and the label is detected by a computer program which identifies the isolate(s))
3. it can be used for rapid analysis of outbreaks and drug-resistant organisms; a single genome can be scanned and analyzed multiple times in a process called "deep sequencing"
4. when DNA fragments are too large for conventional gel electrophoresis methods
85
a process that matches complememtary strands of nucleic acid
| (DNA-DNA, RNA-DNA, RNA-RNA); used for locating specific sites or types of nucleic acid
hybridization
86
15.6 Additional Diagnostic Technologies
87
Lab on a Chip - Infectious Disease Diagnosis
since the development of microarrays, many genetic tests have been miniaturized and placed on chips (integrated circuits) that are:
- easy to use
- require few supplies
- require little technical training
---> they have been facilitated by the used of microfluidics, using miniscule amounts of reagents and fluids to perform reactions that were previously done in test tubes
* PCR methods and DNA and RNA sequencing have been made available on "chips"
BUT: biggest impact on developed countries as in developing countries this form of diagnosis is not possible due to lack of supplies, expertise, or even refrigeration required to store an array of diagnostic reagents
88
utilized for years to determine the structure and composition of various chemical compounds and biological molecules
- --> used alone, and in combination with PCR to provide rapid and highly accurate microbial identification within just minutes
- --> this method, called the MALDI-TOF can be used to analyze a protein fingerprint from pure culture isolates or directly from samples isolated from patient specimens
* **WORKS by adding the pt sample to a metal plate and then striking it with a laser, this causes the sample to be ionized
- > the ions from the sample are guided into a machine that separates them and identifies them according to their mass-to-charge ratio
used for bacteria, fungi, viruses, and is becoming a commonplace utility in clinical and research laboratories due to its ability to produce RAPID, PRECISE, and COST-EFFECTIVE results
Mass Spectrometry
89
one distinct advantage of mass spectrometry
clinical laboratories can construct databases of local strains of microorganisms by running profiles of known microbes; this provides for an infinitely customizable and expandable database
-> can also be used to detect antibiotic susceptibilities
90
diagnostic method that offers a pair of eyes to inaccessible places, and can save the patient an invasive biopsy
-> infections associated with hip implants may be difficult to access through blood samples; the bacteria may be growing in biofilms on the implanted materials, or they may be in an abscess deep in the hip joint, this method allows us to un-invasively investigate
; MRIs, Computerized tomography (CT) scans, PET scans, have been increasingly employed to find areas of localized infection in deep tissue, which can later be biopsied to aspirate samples for culture; or if no infection is found during imaging, the patient has been spared an invasive procedure
Imaging
91
new strategy for identification involving seven genes
used blood from patient to check for the presence of seven genes that host cells express in response to BACTERIAL infection
- > if the genes are active, then the prescriber knows to prescribe an antibiotic; if they are not active than the symptoms are caused by virus(es) and therefore are not going to be helped by antibiotics
* *very important in a society where its estimated that many prescriptions are incorrectly prescribed for conditions that are not caused by bacteria
92
15. 6 OUTCOMES
1. describe the benefits of "lab on a chip: tech for global public health
2. identify an advantage presented by mass spectrometry and also by imaging techniques as diagnostic tools
1. -easy to use
- requires little to no training
- requires few supplies
2. imaging: is less invasive then biopsies; potentially avoids unnecessary invasive procedures
mass spectrometry:
- rapid
- highly accurate
- rapid, precise, and cost-effective
- can construct databases of local strains of micros by running profiles of known microbes
93
mass spectrometry identifies microbes via
a. fluorescent antibodies
b. cell surface carbs
c. protein fingerprints
d. DNA profiling
c. protein fingerprints
94
when using pulsed-field gel electrophoresis, mutations in a microbe's genome will show up as
a different pattern of bands
95
which category of dx is represented by studying a microbe's utilization of nutrients?
phenotypic
96
_______ diagnostic techniques are most likely to be affected by changes in growth conditions of the specimen
phenotypic
97
which of the following techs is most likely to reveal that an infection is in biofilm form?
a. ELISA
b. Whole-genome sequencing
c. PFGE
d. imaging
d. imaging
98
a test that results in a very large number of false POSITIVES probably has an unacceptable level of
sensitivity
*think ebola example in text
