Micro 12 - Penicillins Flashcards Preview

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Flashcards in Micro 12 - Penicillins Deck (24):
1

Which type of Penicillin comes in oral and which one in IV?

Penicillin G : IV form.
Penicillin V : Oral.

2

What are the clinical uses of Penicillin?

1. G(+): S. pneumoniae, S. pyogenes, Actinomyces, Group B Strep.
2. Spirochets: Syphilis.
3. G(+) rods: Clostridium, Listeria, Bacillus.
4. G(-) cocci: Neisseria.

3

What are the toxicities of Penicillin?

1. Hypersensitivity reactions.
2. Hemolytic anemia.
3. Thrombocytopenia.

4

Which are the four penicillinase-resistant penicillins?

Methicillin, Nafcillin, Oxacillin, Dicloxacillin.

5

What is a penicillinase and which type of bacteria have them?

A type of beta-lactamase. Numerous Gram (-) organisms can hydrolyse the beta-lactam ring by bacterial beta-lactamase in periplasm, causing resistance to beta-lactam antibiotics.

6

What are the clinical uses of Penicillinase-resistant penicillins?

S. aureus.

7

When is Methicillin used?

It is used to determine resistant strains of Staph. We do not use it clinically because of toxicity: causes interstitial nephritis.

8

Which one are the aminopenicillins?

Ampicillin and amoxicillin.

9

What are the clinical uses for ampicillin and amoxicillin? Which has a greater oral bioavailability?

They are extended spectrum penicillin.
1. G(+) and G (-); [HEELPSS]:
Haemophilus influenzae
E. coli
Enterococci
Listeria
Proteus mirabilis
Salmonella
Shigella

So they can be used in UTIs, neonatal infections.

10

What is the mechanism of Penicillin?

1. Bind penicillin-binding proteins: no cell wall synthesis.
2. Inhibit formation of cross-linkages between peptidoglycan chains: weak cell wall.
3. Increase the bacterial production of autolysins, and penicillin may upregulate autolysins: death of bacteria.

11

Which one has greater bioavailability: ampicillin or amoxicillin?

Amoxicillin has greater oral bioavailbility. Ampicillin is used more often as an IV form.

12

What is an interesting side effect of aminopinicillin rash?

Causes generalized rash when given for mononucleosis.

13

What are three beta-lactamase inhibitors?

[Central Standard Time]

1. Clavulanic acid
2. Sulbactam
3. Tazobactam

14

What are some common aminopenicillin and beta-lactamase inhibitor combo, and in what pathology do we use it?

1. Amoxicillin + clavulanic acid: resistant otitis media.
2. Ampicillin + sulbactam (IV): surgical infections.

15

What are three important carboxipenicillin and what is a common name for them?

1. Ticarcillin.
2. Carbenicillin.
3. Piperacillin.

They are sometimes called anti-psudomonal antibiotics.

16

In what organisms do we use carboxipenicillin?

1. Pseudomonas.
2. G(-) rods.

17

Which penicillin drug would you use in syphilis?

Penicillin G.

18

Which penicillin drug would you use in UTI?

Amoxicillin.

19

Which penicillin drug would you use in Pseudomonas?

Ticarcillin, carbenicillin, piperacillin.

20

Which penicillin drug would you use in neonatal infection?

Ampicillin + gentamicin.

21

What organisms can be treated with ampicillin or amoxicillin?

1. URIs: Gram (+) and H. influenza
2. UTIs and colonic infections: E. coli, Proteus, Enterococci, and Salmonella.
3. Neonatal infections: E. coli and Listeria.

22

Which three penicillins can be used to treat Pseudomonas infection?

1. Carbenicillin.
2. Ticarcillin.
3. Piperacillin.

23

What are the two different mechanisms of resistance bacteria use to fight penicillin agents?

1. Beta-lactamases to hydrolyze the beta-lactam rings of penicillins.
2. Alteration of beta-lactam targets, the PBPs (Penicillin Binding Proteins).

24

What is the major cause of bacterial resistance to penicillin?

Beta-lactamase production.