Exam 2 Review Flashcards
(123 cards)
1
Q
What are the two methods by which bacteria can acquire new characteristics?
A
Vertical gene transfer and Horizontal gene transfer
2
Q
What are the three major methods of genetic transfer between bacteria?
A
- Transformation
- Transduction
- Conjugation
3
Q
What bacterial cell structure is required for conjugation to occur?
A
Sex pilus
4
Q
What is the importance of the Fertility factor for plasmids?
A
It is a self transferrable plasmid, allowing transfer of itself and other plasmids
5
Q
What are the Mobile Genetic Elements?
A
- Insertion sequences
- Transposons
- Integrons
- Pathogenicity islands
6
Q
What is the function of transposons in the bacterial cell?
A
Transfer antibiotic resistance genes between bacteria
7
Q
What is unique about integrons?
A
Nonmobile
8
Q
What is unique about antibiotic resistance gene cassettes?
A
Allow for multiple antibiotic resistance genes to be inserted into a bacteria’s gene
9
Q
What are the common antimicrobial families/groups used in veterinary medicine?
A
- B lactams
- Aminoglycosides
- Chloramphenicol group
- Tetracyclines
- Macrolides
- Lincosamides
- Polypeptides
- Sulfonamides
- Trimethoprim group
- Fluoroquinolones
- Glycopeptides
- Azole derivatives
10
Q
What is the definition of an antibiotic?
A
Antimicrobial agent originally produced by microbes
11
Q
What is the definition of an antimicrobial?
A
Antibiotics + antimicrobial chemicals originally made in a laboratory
12
Q
What is the process of transcription?
A
DNA -> RNA
13
Q
What is the process of translation?
A
RNA -> protein; read 5’ -> 3’
14
Q
What is the definition of Minimum Inhibitory Concentration (MIC)?
A
Minimum amount of antibiotic that will inhibit growth in vitro
15
Q
What is the definition of Minimum Bactericidal Concentration (MBC)?
A
Minimum concentration of antibiotic that will kill bacteria in vitro
16
Q
What are the five major mechanisms by which bacteria resist the action of antibiotics?
A
- Alteration of target site
- Reduced permeability
- Bypass mechanism
- Modification of drug
- Efflux pump
17
Q
Which families in List A are classified as Bactericidal?
A
- Beta-lactams
- Aminoglycosides
- Fluoroquinolones
- Polypeptides
- Glycopeptides
18
Q
Which families in List A are classified as Bacteriostatic?
A
- Tetracyclines
- Lincosamides
- Sulfonamides
- Azole derivatives
- Chloramphenicol group
- Macrolides
- Trimethoprim group
19
Q
What is the significance of horizontal gene transfer in antibiotic resistance?
A
Antibiotic resistance can be conferred between species leading to superbugs
20
Q
The transfer of genetic material between bacteria via bacteriophages is called?
A
Transduction
21
Q
The transfer of genetic material between bacteria mediated by bacterial pili is called?
A
Conjugation
22
Q
Where does the process of translation take place?
A
Cytoplasm by ribosomes
23
Q
What does Post-Antibiotic Effect (PAE) refer to?
A
Effect antibiotic will have on bacteria even though antibiotic is no longer at MIC
24
Q
Fill in the blank: The term used for the transfer of information from DNA to DNA is called _______
A
Replication
25
Fill in the blank: The term used for the transfer of information from DNA to RNA is called _______
Transcription
26
Fill in the blank: The term used for the transfer of information from RNA to Protein is called _______
Translation
27
What family is the exception to the classification of most antibiotics affecting translation as bacteriostatic?
Aminoglycosides are bactericidal
28
What is the policy of the FDA regarding Extra-Label Use of antimicrobials in animal feeds?
Extra label use of cephalosporin is highly restricted in food animals
29
What is the importance of R-plasmids in bacteria involved in diseases of animals?
They genetically code for the ability of the bacteria to resist antibiotics
30
What does M.I.C. stand for?
Minimum inhibitory concentration
## Footnote
It refers to the lowest concentration of an antibiotic that inhibits the growth of a particular bacteria.
31
What is the Kirby Bauer Disc Diffusion method used for?
To test MIC by assessing bacterial susceptibility to antibiotics
## Footnote
It involves placing antibiotic-impregnated discs on agar plates inoculated with bacteria.
32
Which of the following best describes the M.I.C. of an antibiotic for Salmonella?
e) the in vitro concentration found in a tube dilution test which will inhibit Salmonella
33
Name three antimicrobial groups that are usually Time Dependent Antimicrobials.
* Beta-lactams
* Acetamides
* Tetracyclines
* Macrolides
* Lincosamides
34
How would you maximize the efficiency of Time Dependent Antimicrobials?
Give more often – change from BID to TID
35
Name two antimicrobial groups that are classified as Concentration Dependent Antimicrobials.
* Aminoglycosides
* Polypeptides
* Fluoroquinolones
* Rifampicin
* Sulfa drugs
36
How would you maximize the efficiency of Concentration Dependent Antimicrobials?
Give a higher dose/concentration
37
What is measured in a Kirby Bauer assay?
Bacterial susceptibility to antibiotics
38
Define Pharmacokinetics.
How the body and antibiotic interact
39
Define Pharmacodynamics.
How the microbe and antibiotic interact
40
Which two antimicrobial groups would not work against most anaerobic bacteria?
* Aminoglycosides
* Quinolones
41
Which major group of antimicrobial drugs cannot be given orally for systemic infections?
Aminoglycosides (not absorbed in GIT)
42
What groups of antimicrobials are likely most effective against intracellular bacteria?
* Tetracyclines
* Rifampin/Rifampicin
43
For an immunocompromised patient, which type of antimicrobial should you choose: Bacteriostatic or Bactericidal?
Bactericidal
44
What is the difference between Pharmacokinetics and Pharmacodynamics?
Pharmacokinetics – How the body and antibiotic interact
Pharmacodynamics – How the microbe and antibiotic interact
45
Define Synergistic in the context of antimicrobials.
Effects are compounded
46
Define Additive in the context of antimicrobials.
Effectives are both helpful but individual
47
Define Antagonistic in the context of antimicrobials.
Interactions diminish each other's effects
48
Clavulanic acid is used as a potentiator with which antimicrobial group?
Beta-lactams
49
Trimethoprim is used as a potentiator with which antimicrobial group?
Sulfa drugs
50
What is the major site and mechanism of activity of the penicillins against bacteria?
Blocking transpeptidase from cross-linking peptidoglycan subunits
51
How would you classify penicillins and other Beta-lactam drugs in terms of their ability to kill bacteria?
Bactericidal
52
What are the three major mechanisms bacteria use to resist the activity of penicillins?
* Beta-lactamase production
* Reduced affinity for penicillin binding protein
* Resist penetration through outer membrane
* Presence of efflux pumps
53
What is MRSA?
Methicillin resistant Staph. Aureus
54
What is the mecA gene?
Gives decreased affinity to penicillin binding protein
55
How would you classify the penicillins/cephalosporins based on pharmacokinetics?
Time-dependent
56
Which penicillin can resist the activity of original Beta-lactamases?
Methicillin
57
Is cross-resistance a problem with penicillins?
Yes
58
What is the purpose of combining Clavulanic acid with Amoxicillin in Clavamox?
Improves function of amoxicillin by binding up beta-lactamase
59
How would you classify the Aminoglycosides in terms of spectrum of activity?
Narrow spectrum – gram negative and staph; no anaerobes
60
What is the major site and mechanism of activity of the Aminoglycosides against bacteria?
Ribosome – inhibits translation
61
How would you classify the Aminoglycosides in terms of their ability to kill bacteria?
Bactericidal
62
Is cross-resistance a problem with the Aminoglycosides?
No
63
How would you classify the Aminoglycosides based on pharmacokinetics?
Not absorbed from GIT
64
How would you classify the Aminoglycosides based on pharmacokinetics: Time-dependent or Concentration-dependent?
Concentration-dependent
65
Why does the National Cattlemen's Association recommend against using Aminoglycosides parenterally in food animals?
Leaves residue for 2-4 months
66
How would you classify Chloramphenicol in terms of spectrum of activity?
Broad spectrum
67
What is the major site and mechanism of activity of Chloramphenicol against bacteria?
Ribosome - translation
68
How would you classify Chloramphenicol in terms of its ability to kill bacteria?
Bacteriostatic
69
How would you classify the Acetamides as to pharmacokinetics?
Time-dependent
70
What is the FDA's stance on the off-label use of Chloramphenicol in food animals?
Forbidden due to potential human health problems
71
How would you classify the Tetracyclines in terms of their ability to kill bacteria?
Bacteriostatic
72
What is the major site and mechanism of activity of the Tetracyclines against bacteria?
Ribosome – blocks tRNA (translation)
73
What is the major toxicity problem of the Tetracyclines?
Hepatic and nephrotoxicity (rare)
74
How would you classify the Tetracyclines based on pharmacokinetics?
Time-dependent
75
Is cross-resistance a problem with the Tetracyclines?
Yes
76
How would you classify the Macrolides in terms of their ability to kill bacteria?
Bacteriostatic
77
What is the major site and mechanism of activity of the Macrolides against bacteria?
Ribosome – translation inhibitor
78
How would you classify most of the macrolides: Time-dependent or Concentration-dependent?
Time-dependent
79
How would you classify Lincomycin and Clindamycin in terms of their ability to kill bacteria?
Bacteriostatic
80
What is the major site and mechanism of activity of Lincomycin and Clindamycin against bacteria?
Ribosome - translation
81
For which two groups of bacteria is Lincomycin used as a special purpose drug in swine?
* Spirochete
* Mycoplasma
82
For which group of bacteria is Clindamycin used as a special purpose drug in dogs?
Anaerobic bacteria
83
How would you describe Polymyxin and Bacitracin in terms of structure?
Polypeptide
84
How would you describe Polymyxin and Bacitracin in terms of toxicity?
Highly nephrotoxic
85
What is the major site and mechanism of activity of Polymyxin against bacteria?
Cell membrane - lysis
86
What unique activity does Polymyxin have in treating endotoxemia in horses?
Neutralizes endotoxin (LPS or lipopolysaccharide)
87
What is the major site and mechanism of activity of Rifampin against bacteria?
Inhibits RNA polymerase (transcription)
88
What unique activities does Rifampin have in treating pyogenic conditions in horses?
Can penetrate septic lesions and kill intracellular bacteria
89
How do Vancomycin and beta-lactams differ in their mode of action?
Vancomycin – binds peptides
Beta-lactams – binds transpeptidases
90
The 'Sulfa' drugs are structural analogs of what biological compound?
PABA
91
What is the mode of action of Vancomycin?
Binds peptides
## Footnote
Vancomycin inhibits cross-linking of peptidoglycan in bacterial cell walls.
92
What is the mode of action of Beta-lactams?
Binds transpeptidases
## Footnote
Beta-lactams also inhibit cross-linking of peptidoglycan.
93
What biological compound are 'Sulfa' drugs structural analogs of?
PABA (Para-Amino Benzoic Acid)
## Footnote
PABA is a precursor of folic acid.
94
What biological compound is Trimethoprim a structural analog of?
Dihydrofolic acid
95
What is the major site and mechanism of activity of the Sulfas and Trimethoprim against bacteria?
Folate synthesis
96
How would you classify the activity of the Sulfas?
Broad spectrum
97
Is cross-resistance a problem with the Sulfas?
No
98
What compound do Sulfa drugs work synergistically with?
Trimethoprim
99
How would you classify sulfa/TMP in terms of ability to kill bacteria?
Bactericidal
100
What is the major site and mechanism of activity of the 6-fluoro-quinolones against bacteria?
DNA – prevents supercoiling (DNA gyrase and topoisomerase)
101
How would you classify the 6-fluoro-quinolones in terms of ability to kill bacteria?
Bactericidal
102
How would you classify the 6-fluoro-quinolones in terms of pharmacokinetics?
Concentration dependent
103
How would you classify the 6-fluoro-quinolones in terms of intracellular penetration?
Good
104
Which bacteria are most likely to be susceptible to the 6-fluoro-quinolones?
Gram negative
105
How would you rate the activity of the 6-fluoro-quinolones against anaerobic bacteria?
Low
106
What is the FDA's position on the use of the 6-fluoro-quinolones in food animals?
Forbidden off-label use
107
What is the human health problem associated with the use of 6-fluoro-quinolones in food animals?
High potential for resistance
108
What is the major toxicity problem of Amphotericin B in dogs?
Nephrotoxicity and anemia
109
What is the major toxicity problem of Griseofulvin in cats?
Potential for teratogenic effects
110
Define sterilization.
Process of eliminating all viable organisms
111
Define disinfection.
Process of destroying the infectivity of an object
112
Define antisepsis.
Process of disinfection of living tissue
113
What is pasteurization?
Disinfection of liquid food products by heat
114
Define sanitation.
Reducing the number of microbes to a safe level
115
What is biosecurity?
Management procedures to prevent introduction of new infectious diseases
116
What is biocontainment?
Management practices to reduce risk of spreading disease between animals
117
What is the most important procedure in preventing the spread of pathogens in hospitals?
Wash your hands
118
What are the major factors that determine if a disinfectant will work?
* Concentration
* Presence of organic material
* Necessary exposure time
* Temperature
* pH
* Formulation
119
Which disinfectants are stable in the presence of organic matter?
* Phenols
* Biguanides
120
What disinfectants could be recommended for cleaning after a brucellosis outbreak?
* Chloramine compounds
* Phenolics
121
What should be used to disinfect a trailer after a bluetongue outbreak?
Aldehydes, peroxygens
122
Is pasteurization a sterilization procedure? Why or why not?
No, it only eliminates most pathogenic bacteria
123
Is UV light an effective sterilant for surgical instruments?
Yes, for surface sterilization
