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Flashcards in Penicillin and Cephalosporin Deck (107):
1

What is a synonymn for "Inhibitors of Cell Wall synthesis drugs"?

Beta Lactam Antibiotics

2

What is the specific structure of penicillin?

Beta Lactam ring = 4 membered ring

3

What is important about beta lactam ring in penicillin?

It is strained and reactive.

4

What is a cephalosporin?

A fungally derived drug with a beta lactam ring (penicillin is bacterially derived)

5

What is the character of the beta lactam ring if it is broken?

It doesn't work.

6

What type of bacteria are cell wall synthesis inhibitors most effective against?

Most are gram positive with some gram negative

7

What bacteria are Inhibitors of Cell Wall synthesis drugs effective against?

Spirochetes
Treponema palidum (syphilis) Actinomycoses

8

What organisms are Inhibitors of Cell Wall synthesis drugs not effective against?

Protozoa
Tubercule bacillus
Fungi
Rickettsia
Viruses

9

When are inhibitors of Cell Wall synthesis most effective?

During early infection when bacteria are actively dividing and building cell wall

10

Why are Cell Wall synthesis inhibitor drugs not as effective in later stage infections?

Construction of bacterial cell wall is slower

11

What does a bacterial cell wall do?

Encases bacterial cell membrane

12

What is the character of the cell interior of gram positive bacteria?

Hypertonic

13

What does penicillin inhibit in bacteria?

Inhibits cross linking of cell wall units

14

What happens when the cell wall has holes punched in it by beta lactam drugs?

Membrane ruptures due to inflow of water to hypertonic cell causing rupture.

15

What is required on the bacteria to aide the beta lactam drugs?

Bacterial surface enzymes (autolysins) that cleave previously synthesized cell wall

16

In the absence of bacterial autolysins what Is the character of Beta Lactam drugs bacteriocidal or bacteriostatic?

Bacteriostatic

17

What are the 3 stages of bacterial cell wall synthesis?

1. Production of cell wall building blocks
2. Precursor carried from inside cell membrane to outside
3. Cross linking of cell wall

18

Which Beta lactam drug inhibits the production of Cell Wall Building blocks (Stage I)?

Cycloserine

19

Cycloserine (Stage I cell wall synthesis inhibitor) is used in treating what infection?

Tuberculosis

20

What 2 beta lactam drugs inhibit the precursors being carried from inside the cell membrane to the outside (Stage II)?

Vancomycin and Bacitracin

21

What 2 beta lactam drugs stop the cross-linking of the cell wall (Stage III)?

Penicillin and Cephalosporin

22

How does penicillin inhibit the cross linking of the cell wall?

It is similar to the D-alanyl-D-alanyl terminus of polypeptide side chain of peptidoglycan and occupies D- ala-D-ala substrate site of transpeptide.

23

Beta lactam antibiotics interfere with what steps of cell wall synthesis?

The final steps

24

Cell death requires the action of what?

Autolysins

25

Autolysins act how normally?

They normally nick cell walls for attachment of new peptidoglycan units.

26

What are 4 ways bacteria can become resistant to penicillin?

1. Lack of accessibility to target
2. Production of penicillinases or beta lactamases
3. Altered penicillin binding protein
4. Drug efflux pumps

27

What is an example of lack of accessibility to target for penicillin resistance?

Gram negative bacteria having outer membrane inhibiting access to cell wall.

28

What is the absolute requirement for inhibition of transpeptidase?

Intact beta-lactam ring

29

What is the difference between penicillinase and beta lactamase?

Penicillinase only breaks down penicillin beta lactam ring.
Beta lactamase breaks down both penicillin and cephalosporin beta lactam ring

30

How can gram negative bacteria, who have low production of penicillinases still eliminate antibiotics without being swamped?

Gram negative limits access of beta lactam antibiotics to the peptidoglycan cell wall

31

If an antibiotic binds to Penicillin Binding Protein 2 or Penicillin Binding Protein 3 what will its effects be on the bacteria

Prevents cell division (septum formation) Loss of rod like structure (filament formation)

32

If an antibiotic binds to Penicillin Binding Protein 1 what will its effects be on the bacteria?

Inhibits cell wall synthesis
Organism undergoes osmotic lysis

33

If antibiotic binds PBP 2 and PBP 3 is the effect bacteriocidal or bacteriostatic?

Bacteriostatic

34

If antibiotic binds PBP 1 is the effect bacteriocidal or bacteriostatic?

Bacteriocidal

35

What stage of cell wall synthesis is PBP 1 involved in?

Cross linking step on stage III of cell wall synthesis

36

What can PBP 1 do to itself to resist penicillin?

Change affinity for penicillin

37

What will happen if bacteria increases levels of penicillin binding protein?

It will soak up the penicillin to decrease the effect of penicillin on PBP 1

38

What else can bacteria do to alter their penicillin binding protein to resist penicillin

synthesize new PBP’s with altered penicillin affinity

39

What does a drug efflux pump do?

Pumps the drug out once it gets in cell

40

What is character of broad spectrum penicillin versus narrow spectrum penicillin?

Broad spectrum can be effective against some gram negatives by getting through the outer membrane to attack the inner membrane peptidoglycan

41

Are penicillins widely distributed or narrowly distributed throughout the body

Widely distributed

42

Where do penicillins not distribute well and therefore cannot be used for treatment in these areas of the body?

joints
ocular tissue
cerebrospinal fluid

43

What can cause penicillin to reach higher levels in the central nervous system?

Inflammation

44

What administrative route is most common parenteral route that gives predictable blood level?

Intramuscular

45

What administrative route to use for treatment of severe infection requiring fast action and high blood levels?

Intravenous

46

How much penicillin is absorbed by oral administration?

20-25%

47

How is penicillin eliminated?

Renal

48

How much of penicillin is excreted as active drug?

Two thirds

49

What is the half-life of all penicillins?

Approximately 1 hr

50

Why is probenecid used?

It decreases renal excretion of drugs to increase antibiotic plasma concentration during serious infection.

51

Use of penicillin is limited primarily by what?

Resistance

52

Is penicillin one of the more highly toxic or least toxic drugs in medicine?

One of the least toxic

53

Use of penicillin limited primarily by

Resistance

54

What are 5 toxicities associated with penicillin?

1. Resistance
2. Hypersensitivity
3. Anaphylactic shock
4. CNS effects
5. Superinfection

55

Staph infections acquired in hospital are usually susceptible or resistant to penicillin?

Resistant

56

What respiratory problem increases one’s risk of penicillin hypersensitivity

Asthma

57

Would a penicillin hypersensitivity result in anaphylaxis?

No. It would only cause a rash.

58

What would be the signs of penicillin anaphylaxis?

Bronchoconstriction
Abdominal pain
Nausea
Vomiting
Weakness
Fall in BP

59

What are immediate indicators of anaphylaxis?

dizziness, weakness, sweating, palpitations

60

After a sensitization dose to penicillin, what are likely symptoms?

Rashes, fever, swollen joints several days after taking penicillin

61

When would a person be at risk for penicillin to affect CNS?

When the patient has impaired renal function or is infused w/ unusually high dose

62

What is the risk with long term penicillin therapy

Superinfection

63

What are 4 General classes of penicillins?

1. Penicillin G(benzylpenicillin)
2. Gastric Acid Resistant Penicillin
3. Penicillinase Resistant Penicillins
4. Broad Spectrum Penicillins

64

Standard reference penicillin

Penicillin G (benzylpenicillin)

65

Is penicillin G administered orally?

No. It is inactive at low pH?

66

Can penicillin G get by penicillinases in bacteria, e.g. against Staph aureus?

No it is penicillinase sensitive.

67

Is penicillin G broad or narrow spectrum?

Narrow. Gram positive only.

68

Penicillin G are used in the treatment of what three bacterial infections?

Syphillis, Rheumatic Fever, and Gonorrhea

69

What is the name for Gastric Acid Resistant Penicillin

)Penicillin V (acid stable)

70

What is the importance of Penicillin V?

Itcan be given orally and produces higher blood levels than Pen G

71

How are Penicillin G and Penicillin V similar?

Both are narrow spectrum.

72

What are 4 Penicillinase Resistant Penicillins

1. Methicillin
2. Cloxacillin
3. Nafcillin
4. Dicloxacillin

73

What is the advantage and the disadvantage of Penicillinase Resistant Penicillins

Less susceptible to penicillinases
Narrow spectrum

74

Is methicillin (penicillinase resistant penicillin) administered orally or intravenously?

Intravenously (it is not absorbed orally)

75

Is methicillin as effective as Penicillin G against organisms not producting penicillinase?

No. Only 50% as effective as Pen G

76

Name 3 Broad Spectrum Penicillins.

Ampicillin
Amoxicillin
Carbenicillin

77

Are Broad Spectrum Penicillins active against gram negative or gram positive bacteria?

Gram negative (effectiveness is reduced against gram positive)

78

Are Broad Spectrum Penicillins susceptible to penicillinases?

Yes

79

What is the penicillin-related drug that is front line for tuberculosis treatment?

Cycloserine

80

Which stage of cell wall synthesis does the anti- tuberculosis drug Cycloserine target?

First Stage (Stage I)

81

What penicillin-related drug is last line of defense treating MRSA and also used in Endocarditis?

Vancomycin

82

What is the only place where vancomycin is administered?

At the hospital

83

Which stage of Cell Wall synthesis does Vancomycin inhibit?

Intermediate

84

What intermediate stage cell wall synthesis inhibitor is toxic systemically, but used topically?

Bacitracin

85

Bacitracin is normally paired with what other 2 drugs as a topical ointment (triple-biotic, Neosporin)?

Polymyxin
Neomycin

86

What are 3 agents that can be given in combination with Penicillin or Cephalosporin to increase their activity by breaking down bacterial resistant Beta-lactamase or penicillinase?

Clavulanate
Sulfabactam
Taxobactam

87

Cephalosporins are cell wall inhibitors that are fungally or bacterially derived?

Fungally

88

Cephalosporins are resistant to what?

Penicillinase

89

How are cephalosporins and penicillins similar?

Both have beta-lactam rings

90

What bacteria types are Cephalosporins effective against?

Gram positive and Gram negative

91

Most cephalosporins are administered intravenously or intramuscularly. Which 2 cephalosporins are administered orally

Cephalexin and Cefaclor

92

What is the distribution for Cephalosporins?

Well distributed except to CNS

93

Are most cephalosporins readily metabolized or minimally metabolized?

Minimally metabolized

94

How are cephalosporins excreted?

Kidney

95

What are 2 things that can block cephalosporin excretion in the kidney?

1. Probenecid (med specifically given to decrease excretion to increase drug potency)
2. Renal Failure

96

What is the factor causing the hypersensitivity in penicillin and cephalosporins?

Beta-lactam ring

97

What is an adverse systemic reaction to cephalosporins?

Nephrotoxicity

98

What are 3 infections against which cephalosporins are used?

1. Meningitis
2. Streptococcal
3. Staphylococcal

99

What type of infection/situation necessitates the use of cephalosporins?

Gram negative infection that is penicillin resistant

100

When is Cephalosporin used prophylactically?

During and after surgery for endocarditis.

101

What are 3 classifications of cephalosporins?

1st Generation
2nd Generation
3rd Generation

102

What is the main character of 1st Generation Cephalosporins?

Good against gram positive
Moderate against gram negative

103

First Generation Cephalosporin that can be administered orally?

Cephalexin

104

What is the character of 2nd Generation cephalosporins?

Good against G-
Not very active against G+

105

What is the character of 3rd Generation cephalosporins?

Active against gram negative, especially those producing penicillinase

106

What are 3 ways bacteria can be Cephalosporin resistant?

1. Drug can’t reach target
2. Produce enzyme to disrupt active ring
3. Alter antibiotic binding protein

107

What can pseudomonas and proteus gram negative bacteria produce for Cephalosporin resistance?

Cephalosporinase