Dr. Karatzios -- Antimicrobial Antibiotics Flashcards Preview

Block G -- Infection > Dr. Karatzios -- Antimicrobial Antibiotics > Flashcards

Flashcards in Dr. Karatzios -- Antimicrobial Antibiotics Deck (100)
1

4 potential pathogens that affect the nose and sinus

  • S. pneumoniae
  • GAS
  • S. aureus
  • H. influenzae

2

1 potential pathogen that may affect the throat/pharynx

GAS

3

5 potential pathogens that may affect the lungs/bronchi

  • S. pneumoniae
  • H. influenzae
  • S. aureus
  • Klebsiella spp.
  • Other enterbacteriaceae

4

1 potential pathogen that may affect the middle ear

S. pneumoniae

5

3 potential pathogens that may affect the stomach/duodenum and intestines

  • Salmonella
  • Shigella
  • E. coli O157:H7

6

2 potential pathogens that may affect the urinary tract

  • Enterobacteriaceae
  • Enterococcus

7

5 potential pathogens that may affect the CNS

  • N. meningitidis
  • H. influenzae
  • S. pneumoniae
  • Listeria

8

4 potential pathogens that may affect the eye

  • Haemophilus
  • Moraxella
  • N. gonorrhoeae
  • S. pneumoniae

9

2 potential pathogens that may affect wounds

  • S. aureus
  • GAS

10

3 potential pathogens that may affect bone and joint

  • S. aureus
  • GAS
  • Kingella kingae

11

6 antibiotics that have such good bioavailability that po=IV

  1. Clindamycin
  2. Fluoroquinolones
  3. Septra
  4. Tetracyclines
  5. Metronidazole
  6. Lindezolid

12

2 rate limiting steps that prevent someone from taking antibiotics orally even if bioavailability is so good that po = IV

  • GI tolerance
  • GI absorption (i.e. if patient is nauseated)

13

Define time-dependent activity

Depends on the AMOUNT of time that is spent above the minimum inhibitory concentration of the organism for that specific antibiotic at that specific place/tissue/organ

14

Define concentration-dependent activity

Depends on the CONCENTRATION above the minimum inhibitory concentration of the organism for that specific antibiotic at that specific place/tissue/organ

15

Mechanism of action of beta-lactams

Inhibition of cell wall synthesis by binding to penicillin binding proteins

16

3 modes of resistance that bacteria have developed against beta-lactams

  • Inactivation of antibiotic (penicillinase or beta-lactamase; i.e. most MSSA)
  • Mutated penicillin-binding protein (i.e. MRSA)
  • Decrease in penetration of antibiotics

17

Activity dependence of beta lactams

Time-dependent

18

5 families of beta-lactam antibiotics

  1. Penicillins
  2. Clavulanic acid
  3. Carbapenems
  4. Nocardicins, monobactams
  5. Cephalosporins, cephamycins, cephabacins

19

Organisms typically covered by penicillins

  • Gram-positive
  • Gram-positive anaerobes

20

Reason for S. aureus resistance to penicillin

Penicillinase

21

Reason for gram negative enterobacteriaceae resistance to penicillin

Beta-lactamases

22

Example of a new, resistant pathogen to penicillin

Pseudomonas spp.

23

2 penicillins designed to counter s. aureus and a potential drawback of these

  1. Cloxacillin
  2. Methicillin

Problem: gain in S. aureus activity = loss of anaerobic activity

24

2 penicillins designed to have expanded gram negative coverage (i.e. for e. coli)

  1. Ampicillin IV
  2. Amoxicillin (Amoxil) po

Both = aminopenicillins

25

2 penicillins designed to counter pseudomonas aeruginosa

  1. Ticarcillin
  2. Piperacillin

26

Side effect of beta-lactamase inhibitors

Diarrhea

27

5 types of organisms covered by penicillins + beta-lactamase inhibitors

BROAD SPECTRUM:

  1. S. aureus
  2. Most gram + (i.e. enterococcus and listeria spp.)
  3. Most gram neg. respiratory pathogens (i.e. haemophilus and moraxella spp)
  4. Most gram neg. enteric bacteria
  5. Most anaerobes (gram + and -)

28

6 types of organisms covered by timentin + pip/tazo

BROAD SPECTRUM:

  1. S. aureus
  2. Most gram + (i.e. enterococcus and listeria spp.)
  3. Most gram neg. respiratory pathogens (i.e. haemophilus and moraxella spp)
  4. Most gram neg. enteric bacteria
  5. Most anaerobes (gram + and -)
  6. **AND pseudomonas spp.

29

General trend of activity of cephalosporins

30

Gram negative exceptions to the general trend of cephalosporin activity

Pseudomonas spp.

  • No activity with 1st and 2nd generation
  • 3rd generation = ONLY ceftazidime
  • 4th generation = yes

Campylobacter spp. = no activity with ANY generation

 

31

Gram positive exceptions to the general trend of cephalosporin activity

Enterococcus spp. and Listeria spp. = no activity whatsoever with ANY generation

32

Organisms covered by carbapenems

BROAD SPECTRUM (similar to beta-lactams/beta-lactamase inhibitor combinations)

  • Gram + (MSSA)
  • Gram -
  • Anaerobes

NOTE: Usually resistant to beta-lactamases

33

Recent emergence of what type of organism that is resistant to carbapenems?

Gram-netaive enteric rods

34

3 mild side effects of all beta-lactams

  • GI upset
  • Diarrhea (beta-lactamase inhibitors; cefixime/Suprax)
  • Drug-induced neutropenia

35

2 serious side effects of beta lactams

  • Seizures (up to 14g threshold)
  • Anaphylaxis (10% cross-reactivity between penicillins and carbapenems)

36

Beta lactam that lowers the seizure threshold more than others

Imipenem

37

5 beta-lactams that cross the BBB appreciably

  1. Penicillin IV (high dose)
  2. Ampicillin IV (high dose)
  3. 3rd gen. cephalosporins IV (high dose)
  4. Cefepime
  5. Carbapenems

38

6 Beta-lactams that have activity against MSSA

  1. Cloxacillin po/IV (and methicillin)
  2. Beta-lactam/beta-lactamase combinations (po/IV)
  3. 1st generation cephalosporins po/IV
  4. 2nd generation cephalosporins po/IV
  5. Cefepime
  6. Carbapenems

NOTE: 3rd generation IV NOT that good -- just OK

39

5 beta-lactams with activity against Pseudomonas spp.

  1. Ticarcillin and Piperacillin (IV)
  2. Timentin and Pip/tazo (IV)
  3. Ceftazidime (IV)
  4. Cefepime (IV)
  5. Carbapenems (IV)

40

3 beta-lactams that have activity against anaerobes

  1. Penicillin (po/IV)
  2. All beta-lactam/beta-lactamase combinations (po/IV)
  3. Carbapenems (IV)

41

Mechanism of action of vancomycin

Inhibition of the cross-linking of peptidoglycan

42

Antibacterial spectrum of vancomycin

  • Only gram-positive
  • Includes anaerobic gram-positive
  • Very good against C. difficile (oral)

43

Penetration of vancomycin (3 points)

  • BBB penetration, mainly with inflammation
  • Need higher levels to penetrate BBB, bone and cartilage, heart tissue
  • Need higher levels when dealing with MRSA

44

2 adverse reactions of vancomycin

  1. Nephrotoxicity
  2. Histamine release (red-man syndrome) when administered over short period (< or = 1 hour)

45

2 reasons why nephrotoxicity would occur with vancomycin

  • Usually with accumulation (high trough levels)
  • When co-administered with other nephrotoxic drugs

46

3 manifestations of red-man syndrome

  1. Flushing
  2. Hives
  3. Even hypotension

47

2 types of gylcopeptide antibiotics

Vancomycin

Teicoplanin

48

3 macrolide antibiotics

  • Erythromycin (IV/po)
    • i.e. Erythromycin estolate (po)
  • Clarithromycin (po)
    • i.e. Biaxin
  • Azithromycin (IV/po)
    • i.e. Zithromax

49

Ketolide antibiotic

Telithromycin (po)

Example = Ketek

50

Antibacterial spectrum of macrolides and ketolides (4 types)

  • Gram-positives
  • Gram-negatives
  • Atypical bacteria
  • Non-tuberculous mycobacteria

51

2 gram-positive bacteria that are affected by macrolides/ketolides if S

  • S. pneumoniae
  • GAS

52

2 examples of gram-negatives affected by macrolides/ketolides

  • Campylobacter spp.
  • Bordetella pertussis

53

3 examples of atypical bacteria affected by macrolides/ketolides

  • Mycoplasma spp.
  • Chlamydia spp.
  • Clamydophila spp.

54

2 macrolides that affect non-tuberculous mycobacteria

  • Clarithromycin
  • Azithromycin

55

5  aminoglycosides

  1. Gentamicin
  2. Tobramycin
  3. Amikacin
  4. Streptomycin
  5. Paromomycin

56

General antibacterial spectrum of aminoglycosides

Gram-negative (including Pseudomonas spp.)

57

Exceptions to the gram-negative rule of aminoglycoside coverage (2)

  • Salmonella spp.
  • Neisseria spp.

58

2 bacteria that only some aminoglycosides have activity against

TB and non-TB mycobacteria

59

Aminoglycoside that has anti-parasitic activity and the parasite against which it acts

Paromomycin for giardia lamblia

60

3 adverse reactions of aminoglycosides

  • Renal toxicity
  • Vestibular and cochlear toxicity
  • Muscular blockade

61

2 reasons that renal toxicity may occur with aminoglycosides and whether it is reversible

  1. High trough levels
  2. Increased if co-administered with other nephrotoxic drugs

Reversible = YES

62

Reason for vetsibular and cochlear toxicity with aminoglycosides and whether it is reversible

Usually due to prolonged use

IRREVERSIBLE hearing loss

63

First problem sign of vestibular and cochlear toxicity with the use of aminoglycosides

Tinnitus

64

For which patients should aminoglycosides be avoided

People with neuromuscular diseases (due to muscular blockade)

65

3 fluoroquinolones

  • Ciprofloxacin po/IV (Cipro)
  • Levofloxacin po/IV (Levaquin)
  • Moxifloxacin po (Avelox)

66

The respiratory quinolone

Levofloxacin po/IV (Levaquin)

67

Antibacterial spectrum of fluroquinolone --> trends against:

  • S. pneumoniae
  • MSSA
  • Enteric gram negative rods
  • Pseudomonas spp.
  • Atypicals

68

2 bacteria for which fluoroquinolone coverage is only achieved by 4th generation

  • Enterococcus faecalis
  • Anaerobes

69

Oral vs. IV availability of fluoroquinolones

IV = oral

70

3 sulfonamides

  1. Trimethoprim-sulfamethoxazole (Septra)
  2. Sulfadiazine
  3. Dapsone

71

Antibacterial spectum of Septra (3 main points)

BROAD SPECTRUM -- all bacteria requiring endogenous folic acid synthesis

  • Gram + and gram -
    • Includes:
      • Enterobacteriaceae
      • Shigella
      • S. maltophilia
      • B. cepacia
      • Chlamydia
      • Nocardia

Anti-parasitic activity: Toxoplasma

Anti-fiungal activity: Pneumocystis jeroveci

72

2 organisms against which septra has no activity

  • GAS
  • Enterococcus spp.

73

Oral vs. IV availability of sulfonamides

Oral = IV

74

3 types of organisms covered by tetracyclines

  1. Gram-negative enteric rods
  2. Anaerobes
  3. Atypical bacteria

75

4 types of organisms covered by tigecycline

  1. Gram-negative enteric rods
    • Even those resistant to tetracyclines
    • Multiresistant enterbacteriaceae
  2. Gram-positive
  3. Anaerobes
  4. Atypical bacteria

76

3 types of gram-positive bacteria that are susceptible to tigecycline even though they are resistant to other antibacterials


  • MRSA 

  • VRE 

  • Penicillin-resistant S. pneumoniae
     

77

Oral vs. IV availability of the "cyclines"

Oral = IV

78

Mechanism of actio nof clindamycin

Inhibition of protein synthesis

79

Resistance of clindamycin (2)

  • Modification of target site
  • Efflux pump

NOTE: similar to macrolides (most gram-negatives have intrinsic resistance to macrolides)

80

Activity dependence of clindamycin

Bacteriostatic time-dependent activity

81

Antibacterial spectrum of clindamycin (4 points)

  • Good gram-postiive coverage (incl. S. pneumoniae and S. aureus)
    • ONLY if erythromycin S
  • Good anaerobic activity
  • NO gram-negative coverage
  • NO Entercoccus spp. activity

82

Oral availability equivalence of clindamycin

Oral = IV/IM availability

83

2 adverse effects of clindamycin

  • May cause moderate diarrhea
  • Associated with C. difficile colitis

84

Coverage of metronidazole (2)

  • Anaerobes (gram + and gram -)
    • C. difficile
  • Antiparasitic activity 

85

2 parasites against which metronidazole works

  • Giardia lamblia
  • Entamoaba histolytica

86

Oral availability equivalence of metronidazole

Oral = IV

87

Why shouldn't you use rifamycins alone

On their own, induce RAPID resistance

  • Always use with other antibiotics as buffer
  • Can be used alone as prophylaxis

88

Situation wherein rifamycin can be used alone as prophylaxis

Post-exposure prophylaxis against development of meningitis from N. meningitides and H. influenzae

89

2 treatment uses for rifamycins

  1. TB
  2. Non-TB mycobacteria

90

Major drug interactions of rifamycins

Both are metabolized in the liver and induce CYP-450 enzymes

91

2 rifamycins

  • Rifampin
  • Rifabutin

92

3 general adverse reactions of rifamycins

  • Nausea
  • Increase in liver enzymes
  • Skin rashes

93

Specific adverse reaction of rifampin

Oreange-red coloration of body fluids (urine,tears)

--> May permanent contact lenses

94

2 specific adverse reactions of rifabutin

  • Bronze discoloration of skin
  • Violet-red coloration of urine

95

Only use for nitrofurantoin and why

UTI treatment and prophylaxis

(Therapeutic concentrations achieved ONLY in urine)

96

3 antibiotics specifically produced for multiresistant gram-positive bacteria (MRSA AND/OR VRE)

  1. Oxazolidinones
    • Linezolid
  2. Streptogramins
    • Quinipristin/Dalfopristin
  3. Daptomycin

97

Oral availability equivalence of linezolid

Oral = IV

98

2 averse reactions of linezolid

  • Reversible thrombocytopenia
  • Serotonin syndrome (inhibitor of monamine oxydase)

99

When is there an increased risk of thrombocytopenia when using linezolid

Prolonged treatment >2 weeks

100

2 things to avoid when administering linezolid to a patient

  • Avoid SSRI
  • Avoid or limite tyramine-containing foods (i.e. cheeses, smoked and processed meats)