Intro to Antibiotics Flashcards Preview

Week 6: Pneumonia and Cough > Intro to Antibiotics > Flashcards

Flashcards in Intro to Antibiotics Deck (43):
1

3 general ways to use antibiotics

Empiric
Definitive
Prophylaxis

2

Source control

When all the infection that can be removed is removed
By drainage or surgically

3

Antibiogram

A summary of all the bacterial isolates over a given period of time and what % of them are susceptible to which antibiotics
Every hospital has one

4

4 routes of delivery

PO (by mouth)
IV
IM
PR (by rectum)

5

3 times we should use IV antibiotics

When patients cannot take oral antibiotics
When there is no oral option
When rapid peak serum antibiotic levels are critical

6

6 reasons why patients fail antibiotic therapy

Wrong bug
Wrong drug
Drug is not getting to bug
Wrong diagnosis
Inadequate source control
Too much/too little immune system

7

Bacteriostatic

Drugs slow or stop replication so immune system can eliminate bacteria

8

Bactericidal

Drugs can kill bacteria directly

9

Synergy (and classic example)

2 drugs together have higher bactericidal activity than either alone
Ex: Beta lactam and aminoglycoside

10

Minimal inhibitory concentration

Minimal concentration of the antibiotic needed to inhibit the growth in vitro

11

Time-dependent antibiotic

Activity depends on the duration of time the concentration is over the MIC
Higher dose will not enhance activity
Need to be frequently dosed

12

Concentration-dependent antibiotic

Activity depends on the absolute concentration greater than MIC
A higher dose = higher activity

13

3 general targets of antibiotics

Cell wall synthesis
Nucleic acid synthesis
Protein synthesis

14

Where do
1. Beta Lactams
2. Tetracyclines
3. Macrolides
4. Quinolones
target?

1. cell wall
2. 30S ribosomal subunit
3. 50S ribosomal subunit
4. DNA gyrase

15

4 general types of beta lactams

Penicillins
Cephalosporins
Carbapenems
Monobactams

16

General info about beta lactams

Most common antibiotics
Core beta lactam ring with unique side chain
Time-dependent killing (so need to be frequently doses)
Bactericidal
Safe in pregnancy and for children

17

What is the major mechanism of resistance in gram positive organisms?

Alteration of PBP

18

Efflux pumps

Major resistance mechanism in all bacteria
Active transmembrane pump that expels antibiotics
Can be chromosomal or acquired

19

What is the major mechanism of resistance in gram negative organisms?

B-lactamase

20

2 B-lactamase inhibitors

Tazobactam
Clavulanate

21

What do you use to treat Pseudomonas

Pip-Tazo

22

Can penicillin be used on gram positive or gram negative bacteria?

Gram positive

23

3 main bacteria treated with penicillin

Group A strep (strep pyogenes)
Strep pneumoniae (when sensitive)
Syphillis (treponema pallidum)

24

Main resistance mechanism to penicillin

Penicillinase

25

How do you get MRSA

mecA gene causes alteration of a PBP (PBP2a)

26

Cloxacillin can be used to treat...

Methicillin susceptible Staph aureus

27

Drugs for MRSA
1. PO (4)
2. IV (3)

1. TMP-SMX, Linezolid, Doxycycline, +/- Clindamycin
2. Vanco, Daptomycin, Ceftaroline

28

The amino penicillins (amoxicillin and ampicillin) can be used to treat which 3 bacteria

Streptococci
Enterococcus faecalis
Listeria

29

Cephalosporins do NOT treat which 2 types of bacteria

Enterococcus
Anaerobes

30

As you go down the generations of cephalosporins... (3)

More resistant to beta lactamases
Better activity against gram negative organisms
Better ability to cross into tissue spaces

31

What are
1. first gen
2. second gen
3. third gen
4. fourth gen
5. fifth gen
cephalosporins main clinical uses?

1. Skin and soft tissue infections, surgical prophylaxis
2. Better H, influenzae activity, mild CAP
3. Gonorrhea, serious infections requiring hospitalization, CAP, meningitis, pylonephritis, pseudomonas
4. Empiric for nosocomial infections and neutropenic gever
5. Serious MRSA and ESBL infections

32

Which generation of cephalosporin is best for pseudomonas?
And which carbapenems?

Third gen
Meropenem and Imipenem

33

Carbapenems are used for...

Severe life threatending infections in which ESBL infections are likely
(Nosocomial pneumonia, sepsis)

34

4 adverse events from B-lactams

Hypersensitivity
Gastrointestinal
Renal (rare)
Hematologic (rare)

35

Fluoroquinolones
1. Mechanism
2. 3 bacteria it covers
3. Resistance mechanisms

1. Inhibits DNA gyrase and topoisomerase 4
2. Mycoplasma, Chlamydophila, Leigonella
3. Efflux pumps, alteration of target DNA enzyme and membrane porins

36

4 adverse events from Fluoroquinolones

Tendonitis
Prolonged QTc
Gastrointestinal
CNS (dizziness, insomnia, delirium)

37

Macrolides
1. Mechanism
2. Resistance
3. 2 examples

1. Binds and prevents translocation of peptide chain
2. Efflux pumps, alteration of ribosomal target
3. Clarithromycin, azithromycin

38

Tetracyclines
1. Mechanism
2. 3 examples
3. Works on...

1. Binds and prevents translocation of peptide chain
2. Doxycycline, tetracycline, minocycline
3. Gram positive (including MRSA), gram negative, plasmodium, intracellular bacteria and bacteria without walls

39

2 adverse events from macrolides

GI
Prolonged QTc

40

3 adverse events from tetracyclines

Tooth discolouration
Erosive esophagitis
Photosensitivity

41

4 main resistance mechanisms

Efflux pumps
Porin membrane mutations
Alterations in PBPs
Beta lactamases

42

Drugs for pseudomonas

PO: ciprofloxacin
IV: pip-tazo, ceftazidime, cefepime, meropenem, imipenem

43

Drug for ESBL

Carbapenems