Micro - Antimicrobials (Penicillins) Flashcards Preview

FA - Microbiology > Micro - Antimicrobials (Penicillins) > Flashcards

Flashcards in Micro - Antimicrobials (Penicillins) Deck (31):
1

What are the major forms of Penicillin? Into what broader class of antibiotics are Penicillins classified?

Penicillin G (IV and IM form); Penicillin V (oral); Prototype Beta-lactam antibiotics.

2

What is the mechanism of Penicillin? More specifically, list the 3 major components of its mechanism of action.

(1) Bind penicillin-binding proteins (transpeptidases) (2) Block transpeptidase cross-linking of peptidoglycan (3) Activate autolytic enzymes

3

What is Penicillin mostly used for clinically? What are its other clinical uses?

Mostly used for gram-positive organisms (S. pneumoniae, S. pyogenes, Actinomyces); Also used for Neisseria meningitidis and Treponema pallidum

4

What enzyme is particularly relevant to Penicillin, and what is the impact of this enzyme?

Penicillin is not penicillinase resistant

5

Against what kinds of bacteria is Penicillin bactericidal?

Bactericidal for gram-positive cocci, gram-positive rods, gram-negative cocci, and spirochetes

6

What 2 toxicities are associated with Penicillin?

(1) Hypersensitivity reactions (2) Hemolytic anemia

7

What kind of resistance should be considered with Penicillin?

Penicillinase (a type of Beta-lactamase) cleaves Beta-lactam ring

8

What type of Penicillin are oxacillin, nafcillin, and dicloxacillin?

Penicillinase-resistant penicillins

9

What are 3 examples of Penicillinase-resistant Penicillins?

(1) Oxacillin (2) Nafcillin (3) Dicloxacillin

10

Again, what are the penicillinase-resistant penicillins? What is their mechanism of action and spectrum?

Oxacillin, Nafcillin, Dicloxacillin; Same as penicillin (i.e., block peptidoglycan cross linking), Narrow spectrum

11

Are oxacillin, nafcillin, and dicloxacillin penicillinase-resistant? Why or why not?

Yes; Penicillinase resistant because bulky R group blocks access of Beta-lactamase to Beta-lactam ring

12

For what are penicillinase-resistant penicillins (i.e., oxacillin, nafcillin, dicloxacillin) clinically used?

S. aureus (except MRSA; resistant because of altered penicillin-binding protein target site); Think: "Use NAF (Nafcillin) for STAPH"

13

What are the 2 toxicities associated with penicillinase-resistant penicillins (i.e, oxacillin, nafcillin, dicloxacillin)?

(1) Hypersensitivity reactions (2) Interstitial nephritis

14

What are the aminopenicillins?

(1) Ampicillin (2) Amoxicillin

15

What kind of drugs are Ampicillin and Amoxicillin?

Aminopenicillins

16

What is the mechanism of action for Aminopenicillins (i.e., Ampicillin and Amoxicillin) and spectrum?

Same as penicillin (i.e., block peptidoglycan cross linking), Wider spectrum; Think: "AMinoPenicillins are AMP-ed up penicillin"

17

Are Aminopenicillins pencillinase resistant?

No, Penicillinase sensitive

18

What are Aminopenicillins combined with for therapy, and why?

Also combine with cavulanic acid to protect against Beta-lactamase

19

Compare of the oral bioavailability of the Aminopenicillins.

AmOxicillin has greater Oral bioavailability than ampicillin

20

How are Aminopenicillins used clinically?

Extended-spectrum penicillin - Haemophilus influenzae, E. coli, Listeria monocytogenes, Proteus mirabilis, Salmonella, Shigella, enterococci; Think: Coverage: "ampicillin/amoxicillins HELPSS kill enterococci"

21

What 3 toxicities are associated with Aminopenicillins?

(1) Hypersensitivity reactions (2) Rash (3) Pseudomembranous colitis

22

What is important to note with regard to resistance of Aminopenicillins?

Penicillinase sensitive; Penicillinase (a type of Beta-lactamase) cleaves Beta-lactam ring

23

What are 2 of the Antipseudomal penicillins?

(1) Ticarcillin (2) Piperacillin

24

What kind of drugs are Ticarcillin and Piperacillin?

Antipseudomonal Penicillins

25

What is the mechanism of action of Antipseudomonal Penicillins? What is their spectrum?

Same as penicillin (i.e., block peptidoglycan cross linking), Extended spectrum

26

How are Antipseudomonal Penicillins (e.g., Ticarcillin, Piperacillin) used clinically?

Pseudomonas spp. and gram-negative rods

27

Are Ticarcillin and Piperacillin resistant to penicillinase?

No; Susceptible to penicillinase;

28

What is combined with Antipseudomonal Penicillin therapy, and why?

Use with Beta-lactamase inhibitors (e.g., clavulanic acid); Antipseudomonal Penicillins are susceptible to penicillinase

29

What toxicity is associated with Antipseudomonal Penicillins (i.e., Ticarcillin, Piperacillin)?

Hypersensitivity reactions

30

What are examples of Beta-lactamase inhibitors?

Include Clavulanic Acid, Sulbactam, Tazobactam; CAST

31

What is the clinical use for clavulanic acid, sulbactam, and tazobactam?

Beta-lactamase inhibitors; Often added to penicillin antibiotics to protect the antibiotic from destruction by Beta-lactamase (penicillinase)

Decks in FA - Microbiology Class (43):