Antibiotics Flashcards
(277 cards)
1
Q
Unwinding of the DNA is due to the action of enzymes such as?
A
Helicase, DNA Gyrase, and topoisomerase which break the hydrogen bonds between bases and or hold part of the strand stable.
2
Q
What inserts complementary nucleotides thereby generating a new strand?
A
DNA Polymerase
3
Q
Where are nucleotides always added?
A
the 3’ end. Strand grows in the 5’ to 3’ direction.
4
Q
Which end is exposed in the lagging strand faces toward the fork?
A
has the 5’ end exposed facing toward the fork
5
Q
What is needed to initiate strand growth in the absence of a nucleotide having a 3’ binding site?
A
RNA Primer and RNA polymerase
6
Q
The RNA primer provides?
A
a 3’ site
7
Q
What joins the final nucleotide of the new fragment to the existing strand?
A
DNA Ligase
8
Q
What carries the genetic code from the DNA to the ribosome?
A
Messenger RNA mRNA
9
Q
Transports and then transfers the amino acid to the developing peptide chain
A
Transfer RNA
10
Q
What does the anticodon specify?
A
Which amino acid will be carried by the tRNA
11
Q
What assists protein synthesis by serving as a facilitator for the mRNA and the tRNA functions?
A
Ribosomal RNA
12
Q
The transfer of the genetic code on DNA gene into a messenger RNA (mRNA) strand by means of DNA-dependent RNA polymerase.
A
Transcription
13
Q
Where does RNA polymerase bind to the DNA at?
A
the promoter site
14
Q
What joins the complementary RNA nucleotides together in sequence?
A
RNA polymerase?
15
Q
When does transcription end?
A
the RNA polymerase reaches the termination region of the gene and the new single-stranded mRNA is released.
16
Q
The synthesis of a polypeptide at the ribosome through linkage of amino acids in a sequence specified by mRNA molecule
A
Translation
17
Q
Where does the mRNA attach to during translation?
A
the start codon
18
Q
A tRNA with the complimentary anticodon matches to the codon on the mRNA does what?
A
brings the first amino acid into place
19
Q
the tRNA is released when?
A
As the mRNA codons are matched with complementary tRNA anticodons, the amino acids are linked togethers and the tRNA is released.
20
Q
When is the polypeptide chain released during translation?
A
when the reading frame reaches the stop codon
21
Q
these are constantly expressed
A
constitutive genes
22
Q
genes that can be turned on
A
inducible genes
23
Q
genes that can be turned off
A
repressible genes
24
Q
related genes that are regulated as a group/series
A
Operon
25
Codes for a "repressor" protein which can bind tot he "operator" region
Repressor gene
26
Region of the chromosome which the RNA polymerase binds to during transcription
Promoter site
27
Region of the chromosome which controls access of the RNA polymerase to the structural genes of the operon; site to which the repressor protein bind.
Operator site
28
Adjacent genes of the operon which direct the synthesis of proteins with related functions and which are regulated as a unit
Genes of the Operon
29
Genes are expressed only when certain environmental conditions are present
Inducible operon
30
Genes are expressed except when certain environmental conditions are present
Repressible operon
31
Changes in the sequence of DNA bases, thus changing the genetic code
Mutation
32
What may cause protein changes that may result in changes to metabolic, antigenic, or structural features?
Mutations
33
What are the two types of mutations?
Base Substitution
| Frameshift
34
a single base is replaces with another, thus changing the codon. may results in an improper amino acid in the protein
Base substitution
35
What are the three types of base substitution?
Silent
Missense
Nonsense
36
Insertion or deletion of bases may shift the codon reading frame of the mRNA in the ribosome
Frameshift
37
What does frameshift mutation usually result in?
missnse and sometimes in significantly different, nonfunctional, or incomplete protein
38
What three things are mutations caused by?
Spontaneous mutation
Chemical Mutagens
Radiation
39
gain, loss or substitution of entire gene segments or inversions or transpositions of gene sequences to form new combination of genes.
Recombination
40
Small, circular self replicating piece of DNA in bacteria
Plasmid
41
What is separate from the normal chromosomal DNA?
Plasmid
42
What genes often code for antibiotic resistance or diseases causing factors and can be used in the genetic engineering process?
Plasmid
43
Integration of the DNA of a temperate bacteriophage into the bacterial chromosome where it replicates along with the bacterial chromosome?
Lysogeny
44
Mutation
Viral gene may code for antibiotic resistance or diease-causing factors and produces new bacteriophage upon separation from the bacterial DNA
Lysogeny
45
The transfer of genetic material between donor and recipient cells involving direct cell to cell contact, uses a sex pilus.
Conjugation
46
The direct uptake of DNA segment from one bacterium to another as "naked" DNA in solution. Results in new characteristics for the recipient cell.
Transformation
47
The transfer of DNA from donor bacterium to recipient bacterium by using a bacterial virus as the vehicle. Results in new characteristics for the recipient cells, bacteriophage is not functional
Transduction
48
Agents having no known potential for infecting healthy people
BSL-1
49
Agents most commonly encountered in clinical samples such as HIV and requires lab coat and gloves
BSL-2
50
Agents include those that are more unusual or more highly transmissible such as TB, precautions include level 2 plus routine use of BSC, and HEPA mask
BSL-3
51
Agents are certain highly infectious exotic microbes and toxins for which there is no vaccine or effective treatment and that require the maximum containment facilities
BSL-4
52
Free of all microorganisms and their spores
Sterile
53
Use of physical procedures or chemical agents to destroy all microbial forms, including bacterial spores.
Sterilization
54
Use of physical procedures or chemical agents to destroy, inhibit, neutralize, or remove at least most potentially infectious microorganism on an object or surface.
Disinfect
55
agent or method used to carry out disinfection; normally used on inanimate objects
Disinfectant
56
Use of chemical agents on the skin or other living tissue to eliminate or inhibit microorganisms; no sporicidal action is implied.
Antisepsis
57
-cide -cidal
kills the microbe
58
-stat, -static
prevents growth or multiplication of bacteria
59
Sporicidal
destroys spores
60
Free of contaminating or infectious microorganisms
Aseptic
61
easily altered, decomposed or destroyed by heat
Thermolabile
62
not easily altered, decomposed or destroyed by heat
Thermostable
63
What are the factors affecting the effectiveness and choice of sterilization or disinfection method/agent?
Microbial population composition
Microbial death
Population size
Concentration/intensity of antimicrobial
Duration of exposure
Temperature and pH
Presence of protective or neutralizing matter
Physical nature of materials being treated.
64
What is the order of overall degree of microbial resistance to killing?
```
Bacterial endospores
Mycobacterium
Protozoan cysts
Non-enveloped small viruses
Vegetative bacteria
Fungi
Enveloped viruses
```
65
What dies more rapidly: vegetative cells or spores?
Vegetative cells
66
A larger quantity of contaminating microbes requires a shorter or longer exposure time to destroy?
longer
67
The longer a population is exposed to a microbicidal agent, the more?
organisms are killed
68
what can inactivate enzymes or denature molecules?
Temperature
69
What can directly kill microbes or may enable chemical disinfectants to inactivate microbes faster?
Acids
70
This material protects or inactivates chemical disinfectants, it can protect microorganisms from heating and chemical disinfectants.
Organic matter
71
What are the modes of action of microbial control methods?
Damage to cell wall
Disrupt cytoplasmic membrane
Inhibit synthesis of proteins and nucleic acids
Alter function of proteins & nucleic acids
72
What does damaging the cell wall do ?
Block its synthesis, digest it, or break down its surface
| antibiotics, lysozyme, detergents
73
What does disrupting the cytoplasmic membrane do?
Cause loss of membrane integrity and selective permeability
| detergents (surfactants), heat
74
What does inhibiting synthesis of proteins and nucleic acids do ?
Interference with gene translation, thus preventing protein synthesis
(antibiotics, radiation, formaldehyde)
75
What does altering the function of proteins and nucleic acids do?
Alters bonds that determine secondary and tertiary structure. Altered structure inactivates or denatures functions of enzymes and nucleic acids
(heat, strong organic solvents, phenolics, metallic ions, and antibiotics)
76
What are the methods of physical control of microorganisms?
Cold temperature
Heat (moist, dry, steam, incineration)
Radiation
Filtration
77
What does heat do to the cells of the microbe?
kills cells by disrupting cell membrane functions, denaturing proteins, and inactivating nucleic acids.
Cell membranes become more fluid at elevated temps, causing them to lose their selective permeability
Proteins and nucleic acids are inactivated by breaking their hydrogen bonds, which unfolds proteins and separates double-stranded nucleic acids.
78
What heat is more effective than dry heat? Why?
Moist heat
Moist heat possesses greater heat energy than dry heat
79
What are the conditions of dry heat?
160 to 180 degrees Celsius for two hours
80
What is dry heat used for?
thermostable non-liquid- metal or glass
81
What are the disadvantages of dry heat oven?
liquids cannot be heated above boiling point
| organic compounds may denature above certain temps
82
What are the conditions of steam heat (autoclave)?
121 degrees Celsius for 15 minutes. Large loads may require more than 1 hour so moisture can penetrate all items in the load
The high pressure in the autoclave counteracts vaporization so that heat stable liquids can be heated to 121 Celsius under 15lb of pressure without boiling over. High pressure does not cause the killing
83
What are the limitations of steam heat?
Cannot be used for certain thermolabile substances
| Cannot be used for items adversely affected by moisture- surgical instruments with sharp cutting edges
84
What are the uses of Steam heat?
Sterilization of clean, wrapped instruments, containers and microbial culture media
To render contaminated materials biologically safe before they are discarded
85
What does ionizing radiation- gamma do?
Nonspecifically alters cellular proteins and nucleic acids by penetrating deep into objects
86
What is gamma radiation used for?
Used to sterilize pharmaceuticals, medical/dental supplies, and items that cannot withstand the heat of steam sterilization or the effects of chemicals.
87
What does ionizing radiation- electron beam radiation do?
Alters nucleic acid
88
What is electron beam radiation used for?
Used to decontaminate packages by the postal service
89
What does ultraviolet non-ionizing radiation do?
Nucleic acids mutations that prevent normal gene expression and DNA replication.
90
What are the conditions of ultraviolet non-ionizing radiation
Optimum wave length- 240 to 280 nm (optimum 252 nm)
Low penetrating power- must have direct contact with organism .
Requires lengthy exposure- 10 seconds to 30 minutes depending on distance from UV light source.
91
What are membrane micropore filters?
membrane of cellulose acetate & cellulose nitrate that has a complex system of pores that trap microbes by pore size and chemical affinity to the matrix.
92
What are the conditions of membrane micropore filters?
Pore size- 0.22 micron is usually effective in removing all bacteria
Moderately effective on viruses, mycoplasma, chlamydia, and rickettsia
Used for sterilization of thermolabile liquids.
93
What are the conditions of the HEPA filter?
consist of randomly oriented glass and polymer fibers that effectively remove 99.97% of particles 0.3um and larger.
highly effective at containing particles between 0.3 and 0.1 um and smaller.
Removal of particles is accomplished by adherence of particles to the fibers rather than by sieve in common paper filters.
94
What does boiling heat kill?
vegetative bacteria and resistant bacteria
95
What does dry heat sterilize?
certain thermostable items- glassware
96
What are disadvantages of the autoclave?
Limited volume; costly equipment; thermostable items only
97
What are the disadvantages of the membrane micropore filtration?
Viscous fluids clog; viruses pass through most filters
98
What are the disadvantages for the HEPA filter?
Its for air only
does not remove chemicals
not 100% removal
99
What are the disadvantages of ultraviolet radiation?
Not penetration through regular glass
danger to eyes
lengthy exposure
100
What are the disadvantages of electron beam?
Direct exposures; small containers
101
What are the disadvantages of gamma rays?
Danger to humans; requires special containment.
102
What are high-level disinfectants (definition)?
microbicidal and sporicidal, although some may do so slowly. may become sterile under certain conditions.
103
What are intermediate-level disinfectants (definition)?
Most commonly employed products. effective against vegetative forms of bacteria and maybe effective against fungi and viruses, but a few products will be sporicidal. A few are antiseptics.
104
What are low level disinfectants (definition)?
usually bactericidal; not sporicidal; or tuberculocidal often not fungicidal or virucidal
105
What disrupts structural proteins & enzymes?
Glutaraldehyde
106
What kills vegetative bacteria within minutes and spores in 3-10hr; active solution unstable?
Glutaraldehyde
107
What are the three high disinfectants?
Glutaraldehyde
Hydrogen Peroxide- vap
Chlorine Compounds-gas
108
What are the two sterilants?
Glutaraldehyde
| Hydrogen Peroxide- vap
109
What is an intermediate disinfectant?
```
Hydrogen peroxide- ag
Phenolic compounds
Chlorine- hypochlorite
(Alcohol)
(quaternary ammonium)
(Chlorhexidine)
```
110
What are the low level sporicidals?
Chlorine compounds
111
What are the antiseptics?
```
Hydrogen Peroxide- aq
Iodophors
Alcohol
Quaternary ammonium
Chlorhexidine
```
112
What are corrosive?
Phenolic compounds
| Chlorine compounds
113
Which are inactivated by organic material?
Hydrogen peroxide- minimal
Chlorine Compounds
Iodophors
Alcohol- minimal
114
What creates a formation of hydroxyl free radicals which are toxic to cells?
Hydrogen Peroxide
115
What sterilizes in 6 hours and disinfects in 2-30 minutes?
Hydrogen Peroxide
116
What disrupts cell walls and membranes; precipitates proteins?
Phenolic compounds
117
What inactivates enzymes; damages membranes?
Chlorine Compounds
118
What disrupts metabolic enzymes?
Iodophors
119
What dissolves membrane lipids; may coagulate protein?
Alcohol
120
What is a surfactant, destroys cell membrane; denatures proteins?
Quaternary ammonium
| Chlorhexidine
121
What kills vegetative bacteria within a few minutes, a skin irritant, and D-2-30minutes?
Phenolic compounds
122
What is fact acting, skin & lung irritant, bleach decomposes in a few days; high level disinfection 1-6 hours, regular D 20-30 minutes?
Chlorine Compounds
123
Some residual effect; uses high concentration for equipment. D 2-30 minutes
Iodophors
124
Inactivated somewhat by organic matter. Mild skin and lung irritant; dries skin, flammable, D 1-10 minutes?
Alcohol
125
Benzalkonium=50% up to 80%. Toxic if ingested. Disinfection of 1-10 min.
Quaternary ammonium
126
Residual effects; soluable in water and alcohol; low toxicity. D- few minutes
Chlorhexidine
127
What is a chemical substance of natural, semisynthetic or synthetic origin that inhibits or kills microorganisms and can be used to treat or control infection?
Antibiotic
128
What are the inhibitors of cell wall synthesis?
Beta-lactams- Penicillin's, Cephalosporins
Vancomycin
Bacitracin
Isoniazid
129
What inhibits peptidoglycan synthesis by inhabiting the formation of crosslinks between the polymers of the bacterial cell wall?
Beta-lactams
130
What are cell-membrane enzymes responsible for synthesizing peptidoglycan?
Penicillin binding proteins (PBP)
131
How do beta-lactam antibiotics act?
By binding to PBPs
132
What does binding to the PBP result in?
Inhibition of peptidoglycan synthesis
Degradation of formed cell wall through the release of autolytic enzymes
Weakend cell wall loses integrity and can no longer preserve osmotic pressure. Results in cell death and increased phagocytosis.
133
What acts poorly against existing peptidoglycan and is primarily effective against growing bacteria?
Beta Lactams
134
What are some characteristics of beta lactams?
Very low toxicity
Generally bactericidal
Different groups/generations have different spectrums and resistance
135
Resistance of beta-lactams can occur due to?
Development of changes to pores thus preventing entrance of antibiotic
Prevention of binding of antibiotic to PBP due to modified PBP structure
Hydrolysis of antibiotic by beta-lactamases
136
Binds onto the cross-link peptide, so that the link cannot be completed and peptidoglycan polymer cannot elongate.
Vancomycin
137
Blocks phospholipid carrier that helps carry subunits of peptidoglycan across membrane to cell wall
Bacitracin
138
Inhibits formation of mycolic acid in cell walls of mycobacterium (TB)
Isoniazid
139
What are the inhibitors of protein synthesis
Chloramphenicol, Clindamycin
Erythromycin
Aminoglycosides
Tetracyclines
140
What inhibits accurate translation of mRNA or polypeptide chain formation at the bacterial ribosome?
Inhibitors of protein synthesis
141
What inhibits the polypeptide elongation steps in translation by binding to 50S ribosome subunit and blocking peptide bond formation?
Chloramphenicol, Clindamycin
Bacteriostatic
Broad spectrum
Resistance- due to chemical alteration of either the antibiotic or the ribosomal unit.
142
Binds to 50S subunit; prevents translocation
Erythromycin
143
Inhibits translation by binding to 30S ribosomal protein causing misreading of mRNA and incomplete synthesis of protein molecules?
Aminoglycosides
Bactericidal
Broad-spectrum
Resistance-most commonly results from enzymatic modification of the antibiotic
144
Inhibits translation into polypeptides (proteins) by blocking binding of tRNA to the 30S ribosome mRNA complex?
Tetracyclines
Bacteriostatic
Broad-spectrum
Resistance most commonly results from active efflux of the antibiotic out of the cell or the production or proteins that protect the 30S ribosome.
145
What are the inhibitors of cell membrane function?
Ploymyxins
| Amphotericin B
146
What disrupts functional integrity of cytoplasmic membrane, allowing nucleotides and proteins to escape?
Inhibitors of cell membrane
147
Active against gram-negatives, nephrotoxic
Polymyxins
148
Anitfungal; binds with ergosterol in fungal membranes; somewhat toxic
Amphotericin B
149
What are the inhibitors of nucleic acid?
```
Quinolones
Rifampin
Metronidazole
Nucleoside analogues
Flucytosine, 5-fluorocytosine (5FC)
```
150
Competitive inhibition of essential nucleic acid precursor or binds essential enzyme
Inhibitors of nucleic acid
Most are bactericidal and moderately narrow-spectrum
151
Inhibits bacterial DNA gyrase
Quinolones
152
Inhibits transcription by binding to RNA polymerase and inhibiting initiation of mRNA synthesis
Rifampin
153
Inhibit DNA or RNA synthesis by altering their composition using nucleic acid analogues
Nucleoside analogues
Antiviral, antimicrobics
154
Incorporates into fungal RNA and interferes with DNA and protein synthesis
Flucytosine, 5-fluorocytosine
155
What is the resistance of inhibitors of nucleic acid due to?
typically because decreased uptake into the cells dur to cell wall or cell membrane molecular changes
156
What are the inhibitors of bacterial metabolism?
Sulfonamides
Trimethoprim
Azoles
157
Inhibits folic acid synthesis by competing for precursor molecules
Sulfonamides
158
Competitively interferes with folic acid production by inhibiting a metabolic enzyme
Trimethoprim
159
Antifungal- inhibits synthesis of ergosterol, a key structural molecule of fungal cell membranes?
Azoles
160
Rapid, sensitive but possible less specific, less expensive
Screening/Presumptive
161
Less rapids, more specific, more expensive
Definitive/Confirmatory
162
To dilute the specimen in order to obtain colonies which are physically separated from each other
Isolation
163
Major types of culture mediA
Nutrient
Enriched- provides general nutrients plus various enrichments for fastidious bacteria
Selective- contains ingredients that restrict the growth of certain types of bacteria
Differential (detects pH changes)
164
What does Blood Agar Plate not grow?
Neisseria gonorrhoeae
| Haemophilus infuenzae
165
This media colonies can be differentiate by hemolytic pattern- (alpha, beta, gamma)
Blood Agar Plate
166
What grows most medically significant bacteria?
Supplemented Chocolate Agar
167
What grows gram negative bacilli?
MacConkey Agar
168
What is used for blood culture & other specimens?
Broth media (liquid)
169
What is hemolysis due to on blood agar plate?
bacterial production of enzymes which alter the hemoglobin of red blood cells
Alpha- green zone
Beta- clear zone
Gamma- no change
170
Tests for presence or production of certain enzymes or metabolic products
Biochemical Identification Tests
171
What are the bacterial identification?
Gram Stain
Culture Characteristics
Biochemical Tests
Time to ID- 6-48hr
172
What is yeast grown on? How is it identified?
Blood agar plate
Microscopy
Biochemical tests
antigen tests
173
What do molds grow on?
media with antibiotics
Direct microscopic exam of specimen, microscopic exam of culture; few biochemical tests; few antigen detection tests
174
What do viruses grow on?
grow in living tissue culture cells
antibody detection; antigen detection; gene probe
175
Epitopes must be _____ and sufficient quantity needed
detectable
176
Epitopes must be highly ______ in order to produce accurate test results
specific
177
What can cause a false positive results?
Possibility if Cross-reactive- some Ab Fab sites will bind with very similar, but incorrect antigens
178
The ability of the test to detect very low levels of antigen when it is present? All true positive are detected, includes a low percentage of false-positives.
Sensitivity
```
Expressed as (limit of detection) and (2) Percent Accuracy
Test with high sensitivity may be used as initial screening or presumptive tests
```
179
The ability of the test to accurately detect only the correct antigen or antibody while note reacting with incorrect antigen or antibody?
Specificity
Distinguish cross-reactive and false-positive results from true positives
180
What does overall degree of accuracy of the immunological test depend on?
Quantity of antigen or antibody, exposure to antigen, and any cross-reactivity between non-matching antigen and antibody
181
What are the four immunoassays?
LFI (lateral flow)
Agglutination
Immunofluorescence
ELISA
182
Antigen-Antibody binding is visible by deposit of the bound molecules at the "test line"
LFI
183
Specimen is deposited on one end of the membrane and a wicking pad draws the fluid contain the specimen and reagent through the membrane
LFI
184
The reaction of a particle-sized antigen with its corresponding antibody resulting in macroscopic clumping.
Agglutination Method
185
Relatively low sensitivity, specimen screening in clinic or early lab workup
Agglutination Method
186
The reaction of the bound, labeled antibody with its corresponding antigen is made visible by exposure to ultraviolet light
Immunofluorescence Method
187
Results available in real time, very sensitive and specific. Useful for certain types of agents
Immunofluorescence Method
188
The reacted antigens and antibodies are exposed to a color producing substrate to make antigen-antibody reaction visible.
ELISA
189
Very sensitive, and accurate test- results available from a few minutes to 2 days.
ELISA
190
Increase the number of copies of significant microbial gene sequences so they can be detected. (PCR)
Gene Amplification
191
What do you use to observe gram stain of bacteria?
Oil immersion- high power
192
What do you observe KOH preparation for molds?
Low power
193
What do you observe other wet mount preparations with?
Low or high dry power
194
What are the steps of the smear prep of gram stain?
1) Smear Prep-
smear the specimen on slide
allow to dry in the air
Fix smear to slide by flooding the dry smear with methanol for about 1 minute
195
What are the staining steps of the gram stain?
1. Primary stain- crystal violet- 1 minute then rinse
2. Mordant (Grams iodine)- 1 minute- then rinse with water
3. Decolorizer (acetone & alcohol): 2-5 seconds, then rinse with water
4. Counterstain (Safranin): 30 to 60 seconds, then rinse with water and allow to dry
196
What are the examination procedure steps of gram stain?
1. Allow the slide to dry without heating
2. Focus on objects using the low power lens and low light intensity
3. Change to oil immersion lens to observe details of bacteria; add a drop of oil to the slide, increase the light intensity; focus by using the fine focus knob
197
What are the interpretation steps of gram stain?
Usually reported within 30 to 60 minutes
1. Reaction- Gram pos- blue-violet
Gram neg- pink-red
2. Report stain reaction, cell shape, and cell arrangementt
198
Direct examination of certain unfixed specimens to permit examination of cells in their natural state
Wet Mount
199
What power do you use a wet mount with?
low and/or high-dry power objectives and using reduced light intensity
200
What are some of the wet mount examination types?
KOH
Yeast cells in CSF
Saline wet preparation of vaginal exudate -Trich
201
To determine if the pathogen is susceptible or resistant to a particular set of antimicrobics
Antimicrobic Susceptibility Testing
202
What is empiric therapy?
treating an antibiotic without antimicrobic susceptibility testing
203
The microorganism is not inhibited by the max safe does/concentration of the antimicrobic.
Resistant
204
The microorganism is inhibited (or killed) by the max safe dose/concentration of the antimicrobic. It is a candidate in treating this infection.
Susceptible
205
The microbe may be inhibited by a high dosage that very near the resistant point. Typically interpreted as resistant.
Intermediate
206
Determine which antimicrobics are effective against a particular bacterium at the breakpoint concentration of each antimicrobic.
Disk diffusion testing method
207
What zone indicates that greater concentration of antibiotic has migrated farther away from the disk and/or the bacteria is killed at a low concentration?
A large zone
208
Where will a zone of inhibition (no growth) occur?
Where the antimicrobic concentration is sufficiently high
209
How are the zone sizes interpreted to susceptible, intermediate or resistant?
measurement of size of zone inhibition of growth is interpreted using a detailed chart that converts zone size into the three categories.
210
Determines the minimum concentration of each antimicrobic agent that is effective against the bacterial pathogen
Minimum Inhibitory Concentration (MIC)
211
Interpretation means the antibiotic concentration of at least 2 times the MIC can be achieved at the site of infection.
Susceptible
212
Antibiotic concentration of 2X the MIC cannot be achieved even with the maximum safe dosage
Resistant and Intermediate
213
The close association and interaction of two dissimilar organisms living together
Symbiosis
214
Where are the areas of normal flora?
```
Skin
Nasal
Mouth/Pharynx
Lower GI
Anterior Urethra
Vagina
```
215
Association between organisms in which one is benefitted and the other is neither benefitted nor harmed
Commensalism
216
Both the microbe and the host derive benefits from the relationship
Mutualism
217
What are the four things that can alter the normal flora host relationship?
Prolonged antibiotic therapy
Traumatic injury
Immunological compromise
Hormonal or chemical changes
218
The growth and spread of a pathogen in or on a host resulting in injury to the host tissue
Infectious disease
219
A microbe capable of causing disease by invading tissues, producing toxins, or both
Pathogen
220
The degree of pathogenicity
Virulence
221
What are the two things associated with virulence?
Infectivity - how easily the microbe survives the normal host defenses and establishes infection
Severity - of the damage it causes the infected host
222
What are modes of transmission
Direct contact
Inhalation
Ingestion
Parental
223
What are the Attachment factors that enable the establishment of infection?
Portal of entry
Attachment
Quantity
Quorum-sensing Regulators
224
What are the three things of attachment?
Fimbrae
Surface Chemicals
Adhesive Matrix Molecules
225
What attaches to specific receptor sites on specific tissue?
Fimbrae
226
What dissolve covering of cells and aid chemical attachment?
Surface Chemicals
227
What produces biofilms providing protection for bacteria within harsh human environments?
Adhesive Matrix Molecules
228
What are the Antiphagocytic Factors?
Capsule
Leukocidin
Coagulase
Survival of phagocytosis
229
Causes destruction of white blood cells
Leukocidin
230
causes fibrin clot to form around the microbes
Coagulase
231
Resistance to killing within a phagocyte
Survival of phagocytosis
232
What are the Microbial virulence factors?
```
Attachment & Establishment Factors
Antiphagocytic Factors
Invasive Enzymes
Exotoxins
Endotoxins
Genetic Alterations
Special Antimicrobic Resistance Situations
```
233
Prevent microbe from being engulfed and/or destroyed by white blood cells
Antiphagocytic Factors
234
Factors that promote the invasion and spread of a pathogen in/on the tissue
Invasive Enzymes
235
What are the invasive enzymes?
```
Collagenase
Lecithinase
Hylauronidase
Fibrinolysin & Streptokinase
Hemolysins
Lipase
Proteases
Super Antigens
```
236
Breaks down collagen fibers
Collagenase
237
Destructive to cell membranes of red blood cells and other tissue cells
Lecithinase
238
Breaks down hyaluronic acids in cell membranes
Hyaluronidase
239
Lyses fibrin in blood clots thus preventing isolation of the infection
Fibrinolysin & Streptokinase
240
Dissolve red blood cell membranes
Hemolysis
241
Digest lipids allowing bacteria to enter
Lipase
242
Digest proteins (IgA) thus permitting bacteria to evade entrapment, digestion, etc.
Proteases
243
Cause exacerbated immune or inflammatory response
Super Antigen
244
Cytolytic and Receptor-binding proteins
| Many are dimeric A&B subunits
Exotoxins
245
Tissues affected are vey defined and limited
Super antigens are special group of toxins
Often coded on plasmid of lysogenic phage
Exotoxins
246
Cause specific widespread biological effects on the body, highly potent and elicit good, protective antibodies
Exotoxins
247
"Lipid A" component of gram-negative cell walls which is released upon disintegration of the cell.
Endotoxin
248
Binds to CD14 and TLR 4 on macrophages, B-cells.
Endotoxin
249
Endotoxin stimulates production and release of Acute-phase Cytokines - IL-1, TNF, IL-6 which does what?
Triggers white blood cells to discharge chemicals which induce fever, pain, hemorrhage, blood pressure drops
250
Does not elicit very good or protective antibodies?
Endotoxin
251
Gram-negative bacillus cell wall sloughs off or disintegrates is an example of?
Endotoxin
252
What is code for some exotoxins, antibiotic resistance, and invasive enzymes? passed by conjugation
Plasmid
253
Viral DNA incorporated into bacterial DNA, code for some exotoxins and invasive enzymes?
Lysogeny
254
Pieces of genetic material from one organism are incorporated into the genetic material of another organism.
Gene Recombination,.
255
Many bacteria gain antibiotic resistance by?
Mutated genes
Plasmid encoded genes
Lysogenic virus
256
Presence of an antibiotic-resistant bacterium in the community/hospital leads to?
Survival of the mutant
Increasing numbers of the mutant in the population
Disease problems increase and spread to new geographic locations
257
Bacterial enzyme that inactivates many beta-lactam antimicrobics
Beta Lactamase
258
If a test report is positive for the plasmid encoded gene of beta-lactamase when what kind of antibiotic is used?
antibiotic that is resistant to beta-lactamase
259
Version that affects a larger group of antimicrobics that are typically not affected by typical beta-lactamase
Extended Spectrum Beta-lactamase (ESBL)
260
Mutated MecA gene
MRSA
261
What does the mecA gene encode for?
a low-affinity penicillin binding protein (PBP2a).
262
Mutates genes for outer membrane porins and PBP transpeptides
Carbapenem-Resistant Enterobacteriaceae
| Carbapenem-Producing Enterobacteriaceae
263
```
A form of beta-lactamase
Carried by plasmids
Results in:
Loss of drug diffusion into periplasm
Loss of cross-linking activity of PBP
```
Carbapenem-Resistant Enterobacteriaceae
| Carbapenem-Producing Enterobacteriaceae
264
What are the two host resistant factors?
Non-specific
| Special Factors
265
What are the nonspecific factors?
```
Innate species immunity/resistance
Physical/Mechanical Barriers
Chemical barriers
Phagocytosis
Inflammation
```
266
What are the Physical/Mechanical Barriers?
```
Skin
Mucous Membranes
Cilia of Respiratory tract
Peristaltic action of gut
Normal Flora
```
267
What are Chemical barriers?
```
Acid pH
Bile salts
Lysozyme
Antimicrobial chemicals from normal flora
Interferon
```
268
What does acid pH not denature?
Typhoid & tubercule bacilli, protozoan cysts, polio & hep A
269
What does lysozyme digest?
Gram-positive
270
Human host cell protein produced in response to invasion by certain viruses. It acts as a local defense against certain viruses by producing inhibiting substances that interfere with viral reproduction
Interferon
271
Foreign particles are ingested and digested by polymorphonuclear leukocytes, monocytes, and macrophages
Phagocytosis
272
This develops after mechanical injury or exposure to certain chemicals
Inflammation
273
What is formed during inflammation to enclose the pus that contains phagocytes, dead microbes, dead tissue cells, plasma)
Fibrin clot/wall
274
What are the special factors?
Cell-mediated Immunity
| Antibodies and Complement
275
Antigen stimulates the release of biologically active substances called lymphokines. Lymphokines enhance phagocytosis and killing
Cell-mediated immunity
276
What is it called when an antibody combines with bacterial cells and makes them more susceptible to phagocytosis?
Opsonin
277
What assists the antibody in neutralizing or lysing the bacteria?
Complement
