Antibiotics Flashcards
1
Q
6 general antimicrobial therapy principles
A
- Suspected or known organism
- Antibiotic spectrum
- Bacteria susceptibility to antibiotic
- Concentration of antibiotic at site of infection
- Activity of immune system
- Bacterial resistance mechanisms
2
Q
Interfere with growth or replication but do not kill the organism
A
Bacteriostatic agents
3
Q
Kill the organism
A
Bactericidal agents
4
Q
Lowest concentration of a given antimicrobial at which an organism’s growth is inhibited
A
Minimum inhibitory concentration (MIC)
5
Q
When does MIC increase?
A
With reduced susceptibility
6
Q
What is MBC?
A
Minimum bactericidal concentration
7
Q
What is cell wall acting typically?
A
Bactericidal
8
Q
What is protein synthesis inhibitors typically?
A
Bacteriostatic
9
Q
Is bacteriostatic inhibitory antibiotics concentration lower or higher than bactericidal concentrations?
A
Much lower
10
Q
What do you use for immunosuppressed patients and serious infections?
A
Bactericidal agents
11
Q
How can bactericidal be further divided?
A
Concentration (dependent killing)
Time (dependent killing)
12
Q
What do you want for concentration of bactericidal?
A
Certain peak concentration or AUC
13
Q
When does time of bactericidal continue?
A
Concentration > than MIC (duration of time concentration above MIC)
14
Q
Which part of bactericidal is more important for surgical site injection prophylaxis?
A
Time of bactericidal
15
Q
What is persistent suppression of bacterial growth after antibiotic concentration has fallen?
A
Post antibiotic effect (PAE)
16
Q
What are 3 possible mechanisms for post antibiotic effect?
A
- Persistence of drug at binding site
- Need to synthesize new enzymes
- Slow recovery from damage
17
Q
What is when the bacteriostatic and bactericidal effects of two antibiotic agents used together is greater than their effects when administered alone?
A
Synergism
18
Q
Example of synergism
A
Ampicillin + gentamicin for enterococcal endocarditis
19
Q
5 physical barriers for drug penetration into anatomical compartments
A
- Epithelial and endothelial cell layers
- Hydrophobic/hydrophilic properties of drug
- Molecule charge
- Molecule size
- Membrane transporters (P glycoprotein)
20
Q
4 antibiotic compartment penetration
A
- CNS (blood-brain barrier)
- Eye (from plasma to retina or ocular cavity)
- Pneumonia (pathogens in epithelial lining fluid
- Placental barrier (fetal harm)
21
Q
3 unusual compartments for antibiotic
A
- Endocardial vegetation (heart valves)
2. Biofilm formed by bacteria or fungi (prosthetic devices)
22
Q
Colony of slow growing cells enclosed in an exopolymer matrix
A
Biofilm
23
Q
Is biofilm negative or positive and why?
A
Negatively charged
Restricts antibiotic access
24
Q
2 things that alter pharmacokinetics for antibiotics?
A
Renal impairment
Hepatic impairment
25
Conditions or populations that lead to increased dose requirements of antibiotics
Cystic fibrosis
| Burn patients
26
Does renal impairment or hepatic impairment have more effect on dosage adjustments with antibiotics?
Renal impairment
27
Which drug concentration monitoring to avoid toxicity is used?
Vancomycin
28
Which drug concentration monitoring is established with efficacy?
Aminoglycosides
| Vancomycin
29
What are the 4 different types of selection for antibiotics are there?
Empiric therapy
Definitive therapy
Preventive therapy
Prophylaxis
30
Patient is symptomatic
Empirical therapy
31
Which are the most likely organisms for empirical therapy?
UTI
CAP
SSTI-cellulitis
32
When are situation need immediate treatment with empirical therapy?
Neutropenia
33
Examination of infected secretion or body fluid to determine pathogen
Definitive therapy
34
What is most likely used to narrow antibiotic to target organism with definitive therapy?
Monotherapy
| Combo therapy indicated for certain infections (TB, HIV, hepatitis)
35
What are the 3 types of infections?
Acquired
Normal flora
Deactivation or activation
36
How can you get acquired type of injection?
By the community or health care
37
How can you get normal flora type of injection?
Changes in population or normal body organisms, overgrowth of one becomes a pathogen
38
How can you get reactivating or activation type of infection?
Usually immunocompromised host
Fungal infections
TB
viral, CMV, HSV
39
4 different target microorganism
Bacteria - antibacterial
Viruses - antiviral
Fungi - antifungal
Parasites - antiparasitic
40
3 different classification of antibiotic
Class and spectrum of microorganisms it kills
Biochemical pathway it interferes with
Chemical structure of its pharmacophore
41
4 different classification of antibiotic mechanism of action:
1. Cell wall (or cell membrane) acting
2. Protein synthesis inhibitors
3. Inhibit DNA synthesis
4. Antimetabolites
42
Antibiotic mechanism of action for cell wall acting
Inhibitors of peptidoglycan
43
Antibiotic mechanism of action for protein synthesis inhibitors
Acts on 50S ribosomal unit
| Acts on 30S ribosomal unit
44
What are beta lab tam antibiotics named for?
4 member lactam ring
45
Beta lactam antibiotic
Penicillins
46
Is beta lactam bactericidal or bacteriostatic?
Bactericidal
47
MOA of beta lactams?
Inhibit bacteria growth by interfering with cell wall synthesis
-peptidoglycan (cell wall component)
48
5 different resistance to penicillins
```
Changes in PBPs
Cell entry (size of drug vs porins)
Beta lactamase enzymes
Efflux pumps on gram negative
Biofilms (adhere to devices, valves)
```
49
Anti-staph penicillin
Nafcillin
| Beta lactamase producing staphylococci (streptococci)
50
4 adverse effects of penicillins
Hypersensitivity rxns .4%-7%
Rash, fever, anaphylaxis, vasculitis, SJS
Act as haptens
Seizure (rare with renal insufficiency)
51
MOA of cephalosporins
Similar to PCNs
52
How does cephalosporins spectrum compare?
Broader
53
1st generation of cephalosporins
Cefazolin
| Gram positive, some negative
54
2nd generation of cephalosporins
Increasing gram negative
| Cefotetan
55
3rd generation of cephalosporins
Decreasing gram positive, increasing gram negative
| Ceftriaxone
56
Resistance of cephalosporins
Gram negative enters bacteria ear - produce beta lactamase (inactivate 1st and 2nd generation agents)
57
4 adverse effects of cephalosporins
Hypersensitivity < PCNs
Cross reactivity with penicillin allergy < 10%
Bleeding risk with cefotetan
Disulfiram rxn
58
2 beta lactamase inhibitors
Sulbactam
| Tazobactam
59
Inactivate the beta lactamase to make antibiotic active
Suicide inhibitors
60
Is beta lactamase inhibitors:
Gram positive or negative
Aerobic or anaerobic
Gram negative
| Anaerobic
61
What is vancomycin?
Glycopeptide
- inhibits synthesis of cell wall precursors
- high affinity for D-alanyl D-alanine terminus of cell wall precursor that attaches to the peptidoglycan
- inhibits transpeptidation
62
Is vancomycin gram positive or negative?
ONLY gram positive
63
Example of vancomycin that focuses on gram positive organism
Staph aureus (MRSA)
64
When will vancomycin resistance becomes a problem?
Enterobacter and staph aureus
65
Is vancomycin a beta lactam?
NO
66
Can you use vancomycin if have a penicillin allergy?
Yes because it may be an alternative
67
How is therapeutic drug monitoring done with vancomycin?
Peak and through concentrations
68
Adverse effects of vancomycin
1. Ototoxicity
2. Nephrotoxicity
3. Red-man syndrome
69
What is red-man syndrome?
When you infuse vancomycin too quickly
70
What is aminoglycosides and name the 2 drugs
Protein synthesis inhibitors
Gentamicin
Tobramycin
71
Is aminoglycosides bactericidal or bacteriostatic?
Bactericidal
72
Is aminoglycosides anaerobic or aerobic?
Aerobic
73
Is aminoglycosides reversible?
No
74
Which ribosomal unit does aminoglycosides act on?
30S ribosomal subunit
75
3 possible mechanisms for aminoglycosides:
1. Block of formation
2. Miscoding of AA
3. Block of translocation on mRNA
76
Aminoglycosides PK target peak concentrations
- post antibiotic effect
| - once daily dose
77
What does macrolides do?
Inhibit protein synthesis at 50S
78
If allergic to macrolides, what other antibiotic can you give?
Penicillin
79
Is tetracyclines bacteriostatic or bactericidal
Bacteriostatic
80
What does tetracyclines inhibit with protein synthesis?
30S ribosome subunit
81
Clindamycin MOA
Inhibit protein synthesis like macrolides at 50S
82
Is clindamycin anaerobic or aerobic?
Anaerobic
83
Oxazolidinones (linezolid) MOA
Prevents formation of ribosome complex that initiates protein synthesis at 50S subunit (23S ribosomal RNA)
84
Is oxazolidinones anaerobic or aerobic
Anaerobic
85
How does quinolones block bacterial DNA synthesis?
Inhibit bacterial topoisomerase II (DNA gyrase) and IV
86
What do quinolone drugs end in?
“Floxacin”
87
Which antibiotics inhibit DNA synthesis?
Quinolones
88
Who should you avoid giving quinolone to?
Pregnancy and pediatrics
89
What are 2 antimetabolites?
Trimethoprim (inhibit dihydrofolic acid reductase)
| Sulfamethoxazole (inhibit folate synthesis)
90
What is surgical prophylaxis?
Decrease risk for surgical site infection (SSI)
91
Surgical classification of clean
1-4%
92
Surgical classification of clean contaminated
5-15%
93
Surgical classification of contaminated
16-25%
94
Surgical classification of dirty
30-45%
95
no entry into respiratory, GI, GU tracts or oropharyngeal cavity. Generally elective with no break in technique and no inflammation encountered
Clean
96
entry into the respiratory, GI, GU, biliary, oropharyngeal cavity without unusual contamination. Also includes clean procedures with minor break in technique
Clean contaminated
97
fresh traumatic wounds, gross spillage from GI (no mechanical bowel prep), major break in technique, incisions encountering acute, nonpurulent inflammation
Contaminated
98
procedures involving old traumatic wounds, perforated viscera, clinically evident infection
Dirty
99
When do you want to being first does for surgical prophylaxis?
Infusion 60min prior to incision
100
When do you want to start quinolone or vancomycin for surgical prophylaxis
120min prior to incision
101
When do you redose throughout operative period?
Longer than 4hrs or >2 half lives of antibiotic or major blood loss
102
Duration of prophylaxis
Unnecessary beyond surgery
| Not greater than 24 (48) hrs
103
What does prolong duration of prophylaxis do?
Lead to resistance
104
If have beta lactam allergy, what is an alternative for surgical prophylaxis
Vancomycin
| Clindamycin
105
What is surgical care improvement project (SCIP)
Quality measure to Medicare for public display
106
4 key concepts for SSI prophylaxis
1. Antibiotic choice
2. Dose and therapeutic coverage
3. Timing of pre-op dose
4. Duration of post-op antibiotics
107
What should be used when need 30min prior of pre-op dose
Cefazolin
108
What should be used when need longer infusion time for pre-op dose?
Vancomycin or quinolone
109
5 antibiotics that may affect NMJ
```
Aminoglycosides
Quinolones
Polymyxins
Tetracyclines
Clindamycin
```
110
What are antibiotics additive with
Non depolarizing NM blocker
Volatile anesthetics
Local anesthetics
111
Underlying disease that should be used in caution with antibiotics
Myasthenia gravis
112
3 different varying mechanisms with antibiotics and NM blockers
1. Inhibit pre synaptic ACh release
2. Post-synaptic receptor block
3. Local anesthetic like (inhibit axon AP propagation)
113
How can antibiotics and NM blockade be reversed?
Calcium
| Neostigmine
114
Which drug does not reverse NM blockade with antibiotics
Polymyxin
115
Some general adverse effects of antibiotics?
Reasons to be conservative with antibiotic use
Allergic and allergic-like rxns
Effect on normal flora
Resistance
116
What if pt has penicillin allergy?
Avoid agents with similar side chain
| -penicillins, cefaclor, cefadroxil, cefatrizine, cefprozil, cephalexin, cephradine
117
Which drug does impact oral contraceptive
Rifampin does induce estrogen metabolism that leads to increase clearance
118
What to avoid if patient is pregnant?
- TMP/SMX in 3rd trimester
- doxycycline during all trimester
- quinolones during all trimester
119
Is metronidazole anaerobic or aerobic?
Anaerobic
120
What does mupirocin do?
Inhibits tRNA synthetase
121
3 concerns with ALL antibiotics
1. Hypersensitivity rxn
2. Effect on normal flora
3. Resistance
122
Penicillin:
- or +
Anaerobic or aerobic
-/+
| Anaerobic
122
Piperacillin/tazobactam/sulbactam:
- or +
Anaerobic or aerobic
-
| Anaerobic
122
What is piperacillin?
Antipseudomonal penicillin
122
What is the combo of tazobactam?
Piperacillin and tazobactam
122
What is the combo of sulbactam?
Ampicillin and sulbactam
122
What is Doripenem?
Resistant to beta lactamase
123
Doripenem:
- or +
Anaerobic or aerobic
-/+
| Anaerobic
124
Cefazolin:
- or +
Anaerobic or aerobic
-/+
| Anaerobic
125
Cefotetan:
- or +
Anaerobic or aerobic
Increasing -
| Anaerobic
126
Ceftiaxone:
- or +
Anaerobic or aerobic
Decreasing + and increasing -
| Anaerobic
127
Gentamicin:
- or +
Anaerobic or aerobic
-
| Aerobic
128
Tobramycin:
- or +
Anaerobic or aerobic
-
| Aerobic
129
Erythromycin:
| - or +
+
130
Tetracycline and Doxycline:
| - or +
+
131
Clindamycin:
| Anaerobic or aerobic
Anaerobic
132
Linezolid:
- or +
Anaerobic or aerobic
+
| Anaerobic
133
MOA of metronidazole?
Nitro radical anion targets DNA
134
Metronidazole:
| Anaerobic or aerobic
Anaerobic
135
Mupirocin:
| - or +
+
