Chapter 22: Infectious Diseases I Flashcards
1
Q
Common Bacterial Pathogens for CNS/Meningitis:
A
- Streptococcus pneumoniae
- Neisseria meningitidis
- Haemophilus influenzae
- Group B streptococcus/E. coli (young)
- Listeria (young/old)
2
Q
Common Bacterial Pathogens for Upper Respiratory:
A
- Streptococcus pyogenes
- Streptococcus pneumoniae
- Haemophilus influenzae
- Moraxella catarrhalis
3
Q
Common Bacterial Pathogens for Heart/Endocarditis:
A
- Staphylococcus aureus, including MRSA
- Staphylococcus epidermis
- Streptococci
- Enterococci
4
Q
Common Bacterial Pathogens for Skin/Soft Tissue:
A
- Staphylococcus aureus
- Streptococcus pyogenes
- Staphylococcus epidermidis
- Pasteurella multocida = anaerobic GNR (in diabetes)
5
Q
Common Bacterial Pathogens for Bone/Joint:
A
- Staphylococcus aureus
- Staphylococcus epidermidis
- Streptococci
- Neisseria gonorrhoeae
- GNR (only in specific situations)
6
Q
Common Bacterial Pathogens for Mouth
A
- Mouth flora (Peptostreptococcus)
- Anaerobic GNR (Prevotella, others)
- Viridians group streptococci
7
Q
Common Bacterial Pathogens for Lower Respiratory (Community):
A
- Streptococcus pneumoniae
- Haemophilus influenzae
- Atypicals: legionella, mycoplasma, chlamydophilia
- Enteric GNR (alcoholics)
8
Q
Common Bacterial Pathogens for Urinary Tract:
A
- E. coli
- Proteus
- Klebsiella
- Staphylococcus saprophyticus
- Enterococci
9
Q
Gram-positive organisms stain
A
-Have a thick cell wall and stain dark purple or bluish from the crystal violet stain
10
Q
Gram-negative organisms stain
A
-Have a thin cell wall and take up the safranin counterstain, resulting in a pink or redish color
11
Q
Atypical organism stain
A
Atypicals do not have a cell wall and do not stain well
12
Q
Intrinsic Abx Resistance
A
The resistance is natural to the organism
E.g. E.coli is resistant to vanco because this abx is too large to penetrate the bacterial cell wall
13
Q
Selection Pressure Resistance
A
Resistance occurs when abx kill off susceptible bacteria and leave more resistant strains to multiply
14
Q
Acquired Resistance
A
Bacterial DNA containing resistant genes can be transferred between different species and/or picked up from dead bacterial fragments in the environment
15
Q
Enzyme Inactivation Resistance
A
Enzymes produced by bacteria break down the antibiotic
16
Q
Beta-lactamases
A
Produce beta-lactamases that break down beta-lactams before they can bind to their site of activity
-Beta-lactamase inhibitors are combined with some beta-lactams to extend or preserve their coverage
17
Q
Extended-spectrum beta-lactamases (ESBL)
A
Are beta-lactamases that can break down all PCNs and most cephalosporins. These are treated with carbapenems or new cephalosporin/beta-lactamase inhibitors
18
Q
Carbapenem-resistant Enterobacteriaceae (CRE)
A
Are multi-drug resistant (MDR) gram negative organisms that produce carbapenemase that break down PCN, most cephalosporins, and carbapenems.
Typically require Tx with polymixins
19
Q
Common Resistant Pathogens
A
Kill Each And Every Strong Pathogen K- Klebsiella pneumoniae (ESBL, CRE) E- E. coli (ESBL, CRE) A- Acinetobacter baumannii E- Enterococcus faecalis and faecium (VRE) S- Staphylococcus aureus (MSRA) P- Pseudomonas auruginosa
20
Q
Folic Acid Synthesis Inhibitors
A
- Sulfonamides
- Trimethoprim
- Dapsone
21
Q
Cell Wall Inhibitors
A
- Beta-lactams (PCNs, cephalosporins, carbapenems)
- Monobactams (aztreonam)
- Vancomycin, dalbavancin, telavancin, oritavancin
22
Q
Protein Synthesis Inhibitors
A
- Aminoglycosides
- Macrolides
- Tetracyclines
- Clindamycin
- Linezolid, tedizolid
- Quinupristin/Dalfopristin
23
Q
Cell Membrane Inhibitors
A
- Polymixin
- Daptomycin
- Telavancin
- Oritavancin
24
Q
Hydrophilic Abx
A
- Beta-lactams
- Aminoglycosides
- Glycopeptides
- Daptomycin
- Polymixins
25
Hydrophilic Abx PK parameters
1. Small Vd
2. Renal eliminations (dose adjustments)
3. Low intracellular concentrations (not active against atypicals)
4. Increased clearance and/or distribution in sepsis (consider loading doses)
5, Poor to moderate bioavailability
26
Lipophilic Abx
- Quinolones
- Macrolides
- Rifampin
- Linezolid
- Tetracyclines
27
Lipophilic Abx PK parameters
1. Large Vd (excellent tissues penetration including, bone, lung and brain)
2. Hepatic metabolism
3. Achieve intracellular concentrations (active against atypicals)
4. Clearance/distribution is minimally changed in sepsis
5. Excellent bioavailability (IV:PO ratio is often 1:1)
28
HNPEK
```
Haemophilus
Neisseria
Proteus
E.coli
Klebsiella
```
Gram negative
29
CAPES
```
Citrobacter
Acinetobacter
Providencia
Enterobacter
Serratia
```
30
Beta-lactams MOA
PCN, Cephalosporins, and Carbapenem
Inhibit cell wall synthesis by binding to penicillin-binding proteins (PBPs), this prevents the final step of peptidoglycan synthesis in bacterial cell walls.
31
Natural Penicillins Activity
-Active against gram-positive cocci (streptococci and enterococci) and gram-positive anaerobes (mouth flora). No gram-negative activity
32
Natural Penicillin Drugs
- Penicillin VK
| - Penicillin G Benzathine (Bicillin L-A) IM 1.2-2.4 million units once
33
Antistaphylococcal Penicillins Activity
Cover Streptococci and have enhanced activity against MSSA
34
Antistaphylococcal Penicillins Drugs
Dicloxacillin
Nafcillin (injections
Oxacillin
35
Aminopenicillins Activity
Streptococci
Enterococci
Gram-positive anaerobes (mouth flora)
Gram-negative HNPE
-Combined with a beta-lactamase inhibitor they have added activity against MSSA, HNPEK and B. fragilis
36
Aminopenicillin Drugs
Amoxicillin (Moxatag) (has chewable)
Amox/Clavulantate (augmenting) (has chewable)
Ampicillin (has injections)
Amp/Sulbactam (Unasyn) (only injection) (Both ampicillins must be diluted in NS only)
37
ESBL Activity
```
MSSA
HNPEK
B. fragilis
CAPES
Pseudomonas Aeruginosa
```
38
ESBL Drug
Piperacillin/Tazobactam (Zosyn)
Injection
Extended infusions (over 4 hours)
39
Penicillins should be avoided in which patients?
People with beta-lactam allergies (except syphilis during pregnancy and HIV patients with poor compliance)
People at risk of seizures
40
Outpatient Oral Pen VK used for?
1st line for strep-throat and mild non-purulent skin infections (no abscess)
41
Outpatient Oral Amox use for?
1st line for acute otitis media (90mg/kg/day)
Infective endocarditis prophylaxis
H. pylori
42
Outpatient Oral Amox/Clav used for?
1st line for acute otitis media (90mg/kg/day) and for sinus infections
Use lowest dose of clav to decrease diarrhea
43
Outpatient Oral Dicloxacillin used for?
MSSA only
44
Inpatient Parenteral Pen G used for?
Drug of choice for syphilis (IM 2.4 million units once)
| NOT for IV can cause death
45
Inpatient Parenteral Nafcillin and Oxacillin used for?
MSSA only
| Nafcillin is a vesicant- use through central line only, if extravasation use cold packs and hyaluronidase injections
46
Inpatient Parenteral Piperacillin/Tazobactam used for?
```
Only penicillin active against Pseudomonas
Extended infusions (4hr) can be used to maximize T>MIC
```
47
Penicillins boxed warnings, CI, SE
Boxed warning: Pen G IM only
CI: CrC; <30ml/min do not use ER po amox or amox/clav or 875mg amox/clav
SE: seizure, GI upset, diarrhea, rash (SJS/TEN) hemolytic anemia (+ Coombs test)
48
1st Gen Cephalosporin Activity
Excellent coverage against gram-positive cocci (streptococci and staphylococci), preferred when cephalosporin is used for MSSA
Some activity against PEK (gram neg)
49
1st Gen Cephalosporin Drugs
Cefazolin (ancef)
| Cephalexin (keflex) (PO 250-500mg q6-12h)
50
2nd Gen Cephalosporin Activity
Type 1: cefuroxime that covers staphylococci and HNPEK
| Type 2: Cefotetan and cefoxitin have added gram neg coverage of anaerobes (b. frag)
51
2nd Gen Cephalosporin Drugs
Cefuroxine (ceftin)
Cefotetan (cefotan) (contains a side chain that can increase the risk of bleeding and cause a disulfiram-like rxn to alcohol)
52
3rd Gen Cephalosporin Activity: Group 1
Includes ceftriaxone and and cefotaxime which covers resistant streptococci (s. pneumonia and veridans), staphylcocci (MSSA), gram pos anaerobes, and resistant strains of HNPEK
53
3rd Gen Cephalosporin Activity: Group 2
Includes ceftazidime, which lacks gram pos activity but covers pseudomonas
54
3rd Gen Cephalosporin Drugs: Group 1
Cefdinir (omnicef)
Ceftriaxone (rocephin) (CI in hyperbilirubinemic neonates, causes biliary sludging and kernicterus)
Cefotaxime
55
3rd Gen Cephalosporin Drugs: Group 2
Ceftazidime (Fortaz)
56
4th Gen Cephalosporin Activity
Only cefepime, which has broad spectrum gram neg activity (HNPEK, CAPES, and pseudomonas and gram pos anaerobes
57
4th Gen Cephalosporin Drugs
Cefepime
58
5th Gen Cephalosporin Activity
Only ceftaroline which has gram neg activity similar to ceftriaxone but broad gram pos activity; only beta-lactam that covers MRSA
59
5th Gen Cephalosporin Drug
Ceftaroline fosamil (Teflaro)
60
Cephalosporin warnings, SE
Warnings: Caution with PCN allergy (<10%, higher risk with 1st gen)
SE: Seizures (with accumulation) GI upset, diarrhea, rash, hemolytic anemia (+coombs test)
61
Ceftazidime/avibactam use
Some activity against some CRE and MDR gram neg
62
Cephalosporin Drug Interactions
Cefuroxime and cefpodoxime should be separated from short-acting antacids by 2 hours. H2RAs and PPIs should be avoided
Do not administer ceftriaxone with calcium containing IV fluids (will form precipitate)
63
Cephalosporin class effects
Due to cross reactivity do not choose a cephalosporin on the exam if a pt has a PCN allergy (except acute otitis media in kids)
Risk of seizures of accumulation
64
Cephalosporin Outpatient Oral Uses: 1st gen
Cephalexin (keflex)
Skin infections (MSSA)
Strep throat
65
Cephalosporin Outpatient Oral Uses: 2nd gen
Cefuroxime
Acute otitis media
CAP
Sinus infection (if indicated)
66
Cephalosporin Outpatient Oral Uses: 3rd gen
Cefdinir
CAP
Sinus infection (if indicated)
67
Cephalosporin Inpatient Parenteral Uses: 1st gen
Cefazolin
| Surgical Prophylaxis
68
Cephalosporin Inpatient Parenteral Uses: 2nd gen
```
Cefotetan and Cefoxitin
Anaerobic coverage (B. fragilis)
Surgical prophylaxis (colorectal procedures)
```
69
Cephalosporin Inpatient Parenteral Uses: 3rd gen
```
Ceftriaxone and Cefotaxime
CAP
Meningitis
SBP
Pyelonephritis
```
70
Cephalosporin Inpatient Parenteral Uses: active against Pseudomonas
Ceftazidime (3rd gen)
| Cefepime (4th gen)
71
Cephalosporin Inpatient Parenteral Uses: Ceftaroline
Only beta-lactam with active coverage for MRSA
CAP
Skin and Soft Tissue Infections
72
Carbapenems
They are very broad spectrum abx that are generally reserved for MDR gram neg infections. Cover ESBL producing bacteria but have no coverage of atypical pathogens, MRSA and VRE
73
Ertapenem
Ivanz
Remember does not have activity against PEA (pseudomonas, enterococcus, acinetobacter)
Stable in NS only
74
Meropenem
Merrem
| Carbapenem
75
Carbapenems warnings
Do not use in patients with PCN allergy
Seizures
Monitor renal function
76
Carbapenems Common Uses
Polymicrobial infections (severe diabetic foot infections)
Empiric therapy when resistant organism suspected
Resistant pseudomonas or acinetobacter (except ertapenem)
All are IV only
77
Monobactam MOA
Aztreonam
| Inhibits cell-wall synthesis by binding to PBPs and preventing peptidoglycan synthesis in bacterial cell walls.
78
Aztreonam Uses
Primarily used when allergy to beta-lactams is present can also be used with PCN allergy
Covers many gram negative including pseudomonas.
No gram positive of anaerobic activity
79
Aminoglycoside Uses
Kill gram-negative, including pseudomonas.
| Gentamycin and streptomycin used for synergy in combo with a beta-lactam or vanco for gram positive infections
80
Aminoglycoside Dosing Strategies
Tradition dosing uses lower doses more frequently.
Extended-interval dosing uses higher doses less frequently. With this there is less accumulation, lower risk of nephrotoxicity and decreased cost
81
Aminoglycoside Drugs
Gentamicin
Tobramycin
Amikacin
82
Aminoglycoside Dosing weight
- If underweight use total body weight
| - If obese use adjusted body weight
83
Aminoglycoside Traditional Dosing
Tradition Dosing:
Gent and tobramycin: 1-2.5 mg/kg/dose (trough goal <2mcg/ml for gram neg in gent)
Renal dose Adjustment (traditional)
CrCl >= 60 q8h
84
Aminoglycoside Extended Interval Dosing
Gent and tobramycin
4-7mg/kg
Frequency is determined by a nomogram but starts at q24h
85
Quinolones MOA
Inhibit bacterial DNA topoisomerase IV and DNA gyrase inside the bacteria.
Quinolones have concentration dependent antibacterial activity and have broad spectrum of activity against gram pos, gram, neg, and atypicals
86
Respiratory Quinolones
Levofloxacin, Moxifloxacin, and Gemifloxacin
| Due to enhanced coverage of S. pneumoniae and aytipcals
87
Antipseudomonal Quinolones
Cipro and Levofloxacin (levaquin)
88
Moxifloxacin
Avelox
Has enhanced gram positive and anaerobic activity.
CANNOT be used for UTIs
No renal dose adjustments
89
Delafloxacin
Active against MRSA and is preferred quinolone
90
Quinolones boxed warnings and warnings
Boxed:
Tendon inflammation/rupture
Peripheral neuropathy
Seizures
```
Warnings:
QT prolongation (highest with moxi)
Hypo and hyperglycemia
Psychiatric disturbances
Photosensitivyt
Avoid in children, pregnancy, and breastfeeding
```
91
Quinolone Drug Interactions
Antacids and other polyvalent cations (Mg, Al, Ca, Fe, Zn) can chelate and inhibit quinolone absorption
Lanthanum carbonate and sevelamer can decrease serum concentration of quinolones (separate by 2hr)
92
Ciprofloxacin Drug Interactions
Strong Cyp1a2 inhibitor, weak 3A4 inhibitor and p-gp substrate. Can increase levels of caffeine, theophylline, and tizanidine
93
Macrolides MOA
Bind to the 50S subunit, resulting in inhibition of RNA dependent protein synthesis
94
Macrolides Uses
Atypicals
Community-acquired upper and lower respiratory tract infections
Chlamydia, gonorrhea
95
Azithromycin dosing
Z-pak 500mg on day 1, then 1 tab qd for 4 days
| Tri-pak 500mg qd for 3 days
96
Clarithyromycin
Biaxin
97
Erythromycin
E.E.S, Ery-tab, Erythrocin
98
Macrolide CI, Warnings, SE
CI: Clarith and Eryth do not use with lovastatin or simvastatin
Warnings: QT prolongation, hepatotoxicity
SE: GI upset
99
Common Uses for Azithromycin
```
COPD exacerbations
Chlamydia
Gonorrhea
Prophylaxis for MAC
Severe travelers' diarrhea
```
100
Common Uses for Clarithromycin
H. Pylori
101
Common Uses for Erythromycin
Increases gastric motility and is used for gastroparesis
102
Tetracyclines MOA
Inhibit bacterial protein synthesis by reversibly binding to to the 30S ribosomal subunit
103
Tetracyclines Coverage
Gram positive, gram negative, atypicals
104
Doxycycline Coverage
Vibramycin
CAP, COPD exacerbations
Tick-borne/rickettsial diseases (Lyme disease, Rocky Mountain Spotted fever)
Chlamydia, Gonorrhea
Mild skin infections caused by CA-MRSA, and VRE UTIs
*no renal dose adjustment
105
Minocycline
Minocin, Solodyn
Used for acne
Can cause DILE
106
Tetracyclines Warnings and Notes
Warnings: Children <8 yrs, pregnancy and breastfeeding
Photosensitivity
Notes: IV:PO ratio is 1:1
Doxy sit upright for at least 30 minutes after dose
107
Tetracyclines Drug Interactions
Antacids and other polyvalent cations, sucralfate, bismuth subsalicylate, and bile acid resins can chelate and inhibit absorption
108
Trimethoprim MOA
inhibits dihydrofolic acid reduction to tetrahydrofolate resulting in inhibition of the folic acid pathway
109
Sulfamethoxazole/trimethoprim activity
Many including shigella, salmonella and stenophomonas.
Some opportunistic infections (pneumocystis, toxoplasmosis) but does NOT have activity against pseudomonas, enterococci, atypicals, or anaerobes
110
SMX/TMP dosing
Based on TMP
Uncomplicated UTI 1 DS tab po bid f3d
Pneumocystis Pneumonia (PCP) prophylaxis 1 DS or SS qd
111
SMX/TMP CI, warnings, SE
CI: sulfa allergy
Warnings: skin rxn (SJS/TEN), thrombocytopenic purpura (TTP), G6PD deficiency
SE: photosensitivity, increased k, hemolytic anemia (+ coombs test), crystalluria (take with 8oz of water)
112
SMX/TMP strength
SS: SMX 400mg/ TMP 80mg
DS: SMX 800mg/ TMP 160mg
113
SMX/TMP drug interactions
Increase INR if used in combo with warfarin
| Risk for hyperkalemia is increased in patients with renal dysfunction or if used in combo with ARAs
114
SMX/TMP common uses
CA-MRSA skin infections
UTI
PCP
115
IV Abx that do not need refrigeration
- Metronidazole (flagyl)
- Moxifloxacin (avelox)
- SMX/TMP
- Acyclovir
116
Abx that do not need renal dose adjustment
- Antistaphylococcal PCNs (dicloxacillin, nafcillin)
- Ceftriaxone
- Clindamycin
- Doxycycline
- Macrolides (azith and eryth)
- Metronidazole
- Moxifloxacin
- Linezolid
