Emily Quizlet Exam 2 Flashcards
(207 cards)
1
Q
What do proteases produced by bacteria do?
A
They break down antimicrobial peptides or change the charge of LPS to reduce membrane interaction.
2
Q
What do nucleases released by bacteria help with?
A
They help break down the NETs excreted by neutrophils.
3
Q
What is protein A?
A
A component of S. aureus that binds the Fc region of IgG to render the antibody ineffective.
4
Q
What do antibody proteases do?
A
They cleave antibodies in half to render them useless.
5
Q
What are antibiotics?
A
Antimicrobial agents originally produced by microbes.
6
Q
What are antimicrobials?
A
A broad term that encompasses antibiotics and antimicrobial chemicals originally made in a laboratory.
7
Q
What is selective toxicity?
A
Antimicrobials should exhibit high selective toxicity to inhibit the microbe, yet not affect the host.
8
Q
What does the central dogma refer to in the context of antimicrobials?
A
Many antimicrobials target DNA synthesis, DNA gyrase, or RNA polymerase; these would disrupt the central dogma within the bacteria.
9
Q
What do many antimicrobials target structurally?
A
They target the cell wall or bacterial ribosomes as their mechanism of action.
10
Q
What is a bactericidal antimicrobial?
A
An antimicrobial that kills microbes.
11
Q
What is a bacteriostatic antimicrobial?
A
An antimicrobial that inhibits growth/multiplication of microbes (i.e. body defenses needed to kill bacteria).
12
Q
What is the characteristic of bacteriostatic antimicrobials (except aminoglycosides)?
A
They tend to be bacteriostatic.
13
Q
What is the post antibiotic effect?
A
The effect that antibiotics have on bacteria even with the antibiotic absent.
14
Q
What factors affect antimicrobial effectiveness?
A
They are dependent on drug concentration and the organism itself.
15
Q
When should you use bactericidal drugs?
A
You should use bactericidal drugs when using anti-inflammatory drugs or if the patient is immunocompromised.
16
Q
How can acquisition of antimicrobial resistance occur?
A
Through mutation or natural selection and also through genetic transfer.
17
Q
True or false: Antibiotics cause mutations to occur.
A
False: Antibiotics don’t cause the mutation to occur; they just select for certain bacteria to survive.
18
Q
What is horizontal gene transfer?
A
Gene transfer to an organism that is not a ‘daughter’ or progeny cell.
19
Q
What is vertical gene transfer?
A
Occurs as a result of chromosome replication and cell division; the passing of genetic material to offspring.
20
Q
What are R plasmids?
A
Plasmids that code for resistance to one or many antibiotics; not all of these are self-transferable or mobilizable.
21
Q
What type of gene transfer may occur between or within a species?
A
Horizontal gene transfer.
22
Q
What are some mechanisms of antibiotic resistance?
A
- Alteration of target site 2. Reduced permeability 3. Bypass mechanisms 4. Modification of the drug.
23
Q
What is hydrolysis in the context of antibiotic resistance?
A
Modification of a drug that confers antibiotic resistance can occur through addition or hydrolysis.
24
Q
What is beta lactamase?
A
An enzyme that modifies an antimicrobial (beta lactam drugs, to be specific) by cleaving the drug’s ring to make it ineffective.
25
What happens to acetylated, phosphorylated, or adenylated aminoglycoside antimicrobials?
They are typically inactive.
26
What do some bacteria have that export drugs back out?
Efflux pumps.
27
True or false: Efflux pumps work with the same effectiveness on gram negative bacteria as they do on gram positive bacteria.
False: Gram positive only has one membrane vs. the two membranes of gram negative bacteria, so effectiveness may not be the same.
28
What is the minimum inhibitory concentration?
The minimum level of the antimicrobial that will inhibit growth of the bacteria in vitro.
29
What is the minimum bactericidal concentration?
The concentration of the antimicrobial that will kill the bacteria in vitro.
30
True or false: The minimum bactericidal concentration may be the same or greater than the MIC.
True.
31
True or false: An MBC cannot be determined for bacteriostatic drugs.
True.
32
What is the Kirby Bauer test?
A disk diffusion test to demonstrate which bacteria show antimicrobial resistance.
33
True or false: Recovery time for bacteria post-antibiotic exposure is dependent on MIC.
False: Solely dependent on the organism itself.
34
What can antimicrobials be dependent on?
They can be time or concentration dependent.
35
What are time dependent antimicrobials?
Antimicrobials that need to be above the MIC for 50% of the dosing interval.
36
What are concentration dependent antimicrobials?
Antimicrobials that need an inhibitory quotient 4-10x the MIC to be effective.
37
What do pharmacokinetics refer to?
What the body does to the antimicrobial.
38
What do pharmacodynamics refer to?
What the antimicrobial does to the bacteria.
39
What factors affect the use of an antimicrobial?
1. Attaining a correct disease diagnosis 2. Characteristics of the bacteria 3. Mechanism of action - bacteriostatic vs. bactericidal.
40
Which bacteria do aminoglycosides and fluoroquinolone only affect?
Aerobes.
41
True or false: If a bacteria is sensitive to an antimicrobial in the lab, the bacteria will be sensitive to it within the animal.
False: It may not be.
42
What must the antimicrobial agent be at the site of infection?
Above the minimum inhibitory concentration.
43
What is necessary for the effective use of antimicrobials?
Correct route of administration and adequate dosage.
44
True or false: Distribution of an antimicrobial ingested may be very different depending on location of the tissue.
True.
45
What are tetracyclines known for?
Having superior intracellular antimicrobial activity.
46
What may an antimicrobial agent be chosen against?
Depending on how well it can penetrate into phagocytes.
47
What is a problem concerning pharmacokinetics?
Toxicity and incompatibilities of antimicrobials.
48
What effect can mixing antimicrobials prior to injection have?
An additive, synergistic, or antagonistic effect.
49
What kind of effect do certain antibiotics have when mixed?
Additive effect.
50
What kind of effect does the antibiotic with an arrow have on the one beside it?
Synergistic effect.
51
What kind of effect do the antibiotics in 'C' have on one another?
Antagonistic effect.
52
What is one rationale for using a combination of antibiotics?
To increase the spectrum of activity to cover as many probably causative bacteria as possible.
53
What is another reason for using combinations of antimicrobials?
To decrease the chance of the bacteria developing resistance or to take advantage of synergy.
54
What is another reason for using combinations of antimicrobials?
To allow for lowering of doses of toxic antibiotics.
55
What are disadvantages of using combinations of antimicrobials?
Cost, antagonistic effects, or disturbances in your normal bacterial flora.
56
What is compliance failure?
Failure of a client to comply with recommended antimicrobial therapy regimen.
57
What drugs contain the beta lactam structure?
Beta lactam antibiotics.
58
What do beta-lactam drugs prevent?
Crosslinking in the peptidoglycan cell wall.
59
What do beta-lactams block?
The action of transpeptidases, leading to cell wall rupture.
60
What type of drugs are beta lactam drugs?
Bactericidal.
61
What concern arises from beta-lactam drugs lysing bacteria?
Endotoxin can cause septic shock when gram negative bacteria are treated.
62
What is beta lactamase?
An enzyme produced by bacteria that are resistant to beta-lactam drugs.
63
What does the mecA gene provide?
Resistance to beta-lactam drugs due to reduced affinity of penicillin binding sites on bacteria.
64
What can resistance to beta-lactam drugs develop from?
The bacteria's ability to resist penetration through the outer membrane due to mutated or reduced number of porins.
65
What was the first beta-lactamase resistant drug?
Methicillin; resistance is due to decreased affinity to penicillin binding protein.
66
What are ESBLs?
Extended-spectrum beta-lactamases that render cephalosporins (but not carbapenems) ineffective.
67
What are carbapenemases?
Beta-lactamases that inactivate carbapenems.
68
What is MRSA?
Methicillin-resistant staphylococcus aureus.
69
What are coding genes for beta lactamases often found on?
Plasmids carrying multiple genes to antibiotic resistance.
70
What family does penicillin belong to?
The penicillin family.
71
What is the penicillin family dependent on?
Time dependent.
72
What is the penetration of the penicillin family to the brain and abscesses?
Poor, but inflammation increases penetration.
73
What is the penetration of the penicillin family to most tissues?
Good.
74
What are oxacillin, cloxacillin, dicloxacillin, and methicillin against MRSA?
Non-effective.
75
What are penicillins the drug of choice for?
Many against gram positive bacteria.
76
True or false: Clavulanic acid and sulbactam are antibiotics that are often combined with penicillins to kill bacteria.
False: They only bind to beta-lactamase to prevent degradation of beta-lactam drugs.
77
What are clavamox, timentin, and UnaSyn called?
Potentiated penicillins.
78
What can clavulanic acid and sulbactam bind to?
Beta lactamase so it cannot degrade beta-lactam drugs.
79
True or false: Cephalosporins are widely used by many when treating food animals.
False: They are highly restricted.
80
What do each sequential generation of cephalosporins have?
Greater gram negative antimicrobial properties.
81
What do cephalosporins cause the release of during gram negative systemic infections?
LPS.
82
True or false: Cephalosporins are not effective against MRSA.
True.
83
What family does aminoglycoside belong to?
The aminoglycoside family.
84
What are aminoglycosides effective against?
Gram negative and staphylococcus (gram positive) bacteria.
85
What type of bacteria do aminoglycosides not work against?
Anaerobic bacteria.
86
What type of antimicrobial are aminoglycosides?
Bactericidal.
87
What do aminoglycosides bind to?
The 30S ribosomal subunit to cause 'misreading' of the genetic code.
88
What is cross resistance between aminoglycosides?
Not the rule; each aminoglycoside drug should be tested separately in susceptibility tests.
89
What are aminoglycosides often combined with?
Beta-lactam drugs.
90
What are aminoglycosides dependent on?
Concentration.
91
True or false: Aminoglycosides are readily absorbed by the intestinal tract.
False.
92
Why should aminoglycosides not be used for injection in food animals?
Because of residue problems.
93
What are aminoglycosides known for?
Being the most toxic of the commonly used antibiotics.
94
What family do acetamides belong to?
The acetamide family.
95
What are chloramphenicol and florfenicol?
Both in the family of acetamides.
96
What are acetamides dependent on?
Time.
97
What is florfenicol?
A broad-spectrum bacteriostatic (translation inhibitor) approved for use in pigs and cattle.
98
What family does tetracycline belong to?
The tetracycline family.
99
What do tetracyclines do?
They are bacteriostatic and inhibit protein synthesis by blocking tRNA binding to the 'A' spot in the ribosome.
100
What are tetracyclines often the drug of choice for?
Broad-spectrum and often the drug of choice in food animals.
101
True or false: All tetracyclines have the same spectrum of activity.
True.
102
What are tetracyclines dependent on?
Time.
103
What are tetracyclines known for?
Being well absorbed, penetrating into most tissues (including CSF), and used to treat intracellular bacteria.
104
Why do we tend not to use tetracyclines on young animals?
Because they bind to calcium of bones and teeth, leaving a stain.
105
What may tetracyclines activate?
Latent salmonella infections in horses.
106
What may develop with tetracyclines?
Resistance.
107
What are well absorbed and used to treat intracellular bacteria?
Tetracyclines
## Footnote
They penetrate into most tissues including CSF.
108
Why do we tend not to use tetracyclines on young animals?
They bind to calcium of bones and teeth, leaving a stain.
109
What may activate latent salmonella infections in horses?
Tetracyclines
110
What may develop resistance with long term administration?
Tetracyclines
## Footnote
If resistant to one, usually resistant to all of them in this family.
111
What family does the macrolide antimicrobial structure belong to?
Macrolide family
112
What are bacteriostatic drugs that interfere with protein synthesis?
Macrolides
113
Are macrolides time or concentration dependent?
Time dependent
114
What is a narrow-spectrum drug that we tend not to use on horses due to GI upset?
Erythromycin
115
What is a narrow-spectrum drug effective on gram positive bacteria, mycoplasmas, and spirochetes?
Tylosin (lincomycin also acceptable here)
116
What type of macrolide includes azithromycin, clarithromycin, and gamithromycin?
Azalides
117
What should not be used in adult roses due to serious GI disturbances?
Erythromycin and the azalides
118
What type of macrolide should not be accidentally injected due to significant human toxicity?
Tilmicosin
119
What family of antimicrobials includes lincomycin, clindamycin, and pirlimycin?
Lincosamides
120
Are lincosamides time or concentration dependent drugs?
Time dependent
121
What are often used in the same situation due to their effectiveness on gram positives?
Lincomycin and tylosin
122
What is clindamycin used on?
Anaerobic bacteria in dogs and cats & gram positive cocci
123
What is noted for its ability to penetrate into abscesses and bony tissues?
Lincomycin
124
What binds to site 2058 on the ribosome to inhibit protein synthesis?
Erythromycin, lincomycin, and streptogramin
125
What resistance gene is widespread in gram positive bacteria?
ermC
## Footnote
It encodes for an rRNA methylase that provides resistance.
126
What family does the polypeptide antimicrobial structure belong to?
Polypeptide family
127
What family is bactericidal and damages/lyses the outer leaflet of bacterial membranes?
Polypeptide family
128
What family doesn't inhibit the ribosome and isn't a protein?
Polypeptide family
129
What covers gram negative bacteria and has an antipyretic effect?
Polymyxins
130
What family of antimicrobials is used topically in antibiotic creams?
Polypeptides
131
What is a bactericidal polypeptide that interferes with cell wall synthesis?
Bacitracin
132
True or False: Bacitracin and polymyxins are both in the same major class but have opposite spectra.
True
133
What is a bactericidal antimicrobial that inhibits RNA polymerase?
Rifampicin
134
What antimicrobial is known for its ability to penetrate septic lesions?
Rifampicin
135
What bactericidal antimicrobial binds to peptides in peptidoglycan?
Vancomycin
136
What drug is primarily used in horses for gram positive bacteria?
Rifampicin
137
What drugs predates the use of penicillin by many years?
Sulfonamides
138
What out-competes PABA in the binding site of its enzyme?
Sulfonamides
139
What is a broad-spectrum drug that is not good with pus and tissue necrosis?
Sulfonamides
140
True or False: Resistance to one sulfonamide generally means there is resistance to all of them.
True
141
What works synergistically with sulfonamides?
Trimethoprim
142
What is an antagonist of folic acid often used with sulfonamide?
Trimethoprim
143
What are antagonists of PABA in the folic acid pathway?
Sulfonamides
144
What are broad spectrum and bactericidal when combined with sulfonamide?
Trimethoprim
145
What are trimethoprim/sulfonamide drugs together called?
Potentiated sulfonamides
146
What family of drugs does quinolone belong to?
Quinolone family
147
What is the mechanism of action for quinolones?
They make DNA gyrase or TopoIV ineffective.
148
What family of antimicrobials has widespread tissue penetration but is limited to aerobic gram-negative bacteria?
Quinolones
149
What family of antimicrobials is increasingly less effective against campylobacter, salmonella, and e. coli?
Quinolones
150
What is bactericidal against anaerobic bacteria?
Nitromidazoles
151
What sterol is present in the plasmalemma of fungi?
Ergosterol
152
What binds ergosterol and creates pores to lyse the cell?
Amphotericin B (and also nystatin)
153
What do azole derivatives inhibit in fungi?
The synthesis of ergosterol
154
Are azole derivatives fungistatic or fungicidal?
Fungistatic
155
What also inhibits synthesis of ergosterol and is fungicidal against dermatophytes?
Terbinafine
156
What inhibits nucleic acid synthesis and cell mitosis of fungi?
Griseofulvin
157
What fluorinated pyrimidine inhibits RNA synthesis?
5-fluorocytosine
158
What is the removal of organic debris that must precede disinfection?
Cleaning
159
What is the process of destroying the infectivity of an object?
Disinfection
160
What reduces the number of microbes to a safe level?
Sanitation
161
What is the process of disinfection of living tissue?
Antisepsis
162
What disinfects liquid food products by heat?
Pasteurization
163
What is the process of eliminating all viable organisms from a material?
Sterilization
164
Who was the first proponent of disinfection and promoted washing hands?
Semmelweis
165
What are heat, irradiation, filters, and gases considered in sterilization?
Physical methods
166
What are aldehydes, alcohols, quats, peroxides considered in sterilization?
Chemical methods
167
What is the use of heat, moisture, and pressure at 121ºC for 15 minutes?
Autoclaving
168
What is used for glassware and metal objects to avoid water residues?
Dry heat sterilizer
169
What is the LTLT method of pasteurization?
63ºC for 30 minutes
170
What is the HTST method of pasteurization?
72ºC for 15 seconds
171
True or False: Ordinary pasteurization is a sterilization procedure.
False
172
What is UHT pasteurization?
138ºC for 1 sec
173
What high energy method is used to sterilize materials in industry?
Ionizing radiation
174
What is used for surface sterilization but does not penetrate well?
UV light irradiation
175
What method performs liquid or gas sieving?
Filtration
176
What size filter will get you particle removal with 99.97% efficiency?
0.3 um (HEPA filters)
177
What gas is used for instruments and heat-labile materials?
Ethylene oxide
178
What is the most important factor affecting the activity of biocides?
Concentration
179
Do most disinfectants work better at colder or warmer temperatures?
Warmer
180
What level disinfectants are effective against vegetative bacteria?
Low level
181
What level disinfectants are effective against mycobacterium spp.?
Medium level
182
What level disinfectants are effective against bacterial spores?
High level
183
What alkylating gas agent is no longer used except in aqueous form?
Formaldehyde
184
What is more reactive than formaldehyde and used in cold sterilization?
Glutaraldehyde
185
What are oxidizing agents whose activity is dependent on concentration?
Peroxygens
186
What concentration of hydrogen peroxide is sporicidal?
30%
187
What is the mechanism of action for alcohols?
Dehydration and denature proteins
188
What must alcohols completely do for antimicrobial action to be effective?
Dry
189
What is household bleach effective in many dilutions?
Hypochlorite
190
What is hypochlorite corrosive to?
Metal
191
What halogen is used for skin antiseptics and surgical scrubs?
Iodine
192
What is aqueous iodine?
Lug's solution
193
What is tincture of iodine?
2% or 7% iodine in alcohol
194
What are iodine plus surfactant called?
Iodophors
195
What disinfectant works by denaturing proteins?
Phenols
196
What disinfectant has been replaced by less caustic and less toxic derivatives?
Phenols
197
What disinfectant has medium disinfectant activity?
Halogens and phenolics
198
What disinfectant is toxic to cats?
Phenolics
199
What are cationic detergents that denature the cell membrane?
Quats (quaternary ammonium compounds)
200
What inactivates quats?
Soaps, hard water, and organic material
201
What is the mechanism of action for biguanides (chlorhexidine)?
Oxidize material
202
What disinfectant destroys the cytoplasmic membrane?
Anilides
203
What disinfectant is used against gram negative bacteria?
EDTA
204
What is EDTA great for topical use?
Otitis externa, rhinitis/sinusitis, and incisional infections
205
What is a system of management procedures designed to prevent new infectious diseases?
Biosecurity
206
What is a system of management practices directed at reducing the risk of spreading an existing disease?
Biocontainment
207
What is the goal of sanitation and disinfection?
Reduce the bacterial population to a level that the animals can tolerate.
