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Infection and Immunity 2- Lecture 2 and 3
Penicillins and Cephalosporins
59
Medical
Professional
04/27/2013

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Cards

Term
3 Kinds of antibiotics that have been increasing in use since 1922 (all others are decreasing)
Definition

Azithromycin/clarithromycin

Amox/Clav (<15 yo)

Fluroquinolones (>15 yo)

Term
Give the MOA for β-Lactam antibiotics
Definition

1. They diffuse through the peptidoglycan of gram +  bacteria and bind to penicillin binding proteins, inhibiting cell wall synthesis.

2. They also activate autolytic enzymes

Term

3 ways bacteria resist B-Lactam antibiotics

Definition

1. Inactivate it with B-Lactamase (destroys the B-Lactam ring)

2. Alter peptidoglycan binding proteins so they don't bind well

3. Reduce their outer membrane permeability so antibiotic can't get in (mostly in gram negative bacteria, loss of outer membrane porin)

Term
4 antibiotics that are desroyed by B-Lactamases
Definition

1. Penicillins

2. Cephalosporins

3. Monobactams

3. Carbapenems

Term
All B-Lactam antibiotics are ___ dependent in order to work.
Definition
time-dependent
Term
MIC means _______ when referring to antimicrobial drugs.
Definition
Minimum amount needed to inhibit microbial growth.
Term
Penicillin G is a ___
Definition
Natural penicillin
Term
Natural Penicillins (like penicillin g) are effective at killing ________, ______, and ________ (be specific)
Definition

1. Non B-Lactamase producing gram + cocci

2. Neisseria meningiditis (gram - cocci)

3. Non-penicillinase-producing Neisseria gonorrhoeae (gram - cocci)

Term
Methicillin is a ___
Definition
Penicillinase-resistant penicillin
Term
Nafcillin is a ___
Definition
Penicillinase-resistant penicillin
Term
Oxacillin is a ___
Definition
Penicillinase-resistant penicillin
Term
Cloxacillin is a ___
Definition
Penicillinase-resistant penicillin
Term
Dicloxacillin is a ___
Definition
Penicillinase-resistant penicillin
Term
Phenoxymethyl penicillin is a ___
Definition
Natural penicillin
Term

Penicillinase-resistant penicillin is resistant because ___.

+ What microbe produces penicillinases?

Definition

- has a side chain that protects the B-lactam ring

 

- Staphylococcus make penicillinases

Term
Ampicillin is a ___
Definition
Aminopenicillin
Term
Amoxicillin is a ___
Definition
Aminopenicillin
Term
Bacampicillin is a ___
Definition
Aminopenicillin
Term
Aminopenicillins are effective against ___, ___, & ___.
Definition

1. gram +s

2. enterococcus (better than natural penicillins)

3. Listeria

Term
___ and ___ are resistant to aminopenicillins and why.
Definition

1. Staphylococcus (make penicillinases)

2. Gram negative B-lactamase producers

Term
Give the difference between aminopenicillins and natural penicillins.
Definition
Aminopenicillins are acid stable and work better against g- bacteria.
Term
3 adverse effects from aminopenicillins.
Definition

Ampicillin-specific rash

Diarrhea

Pseudomembranous colitis

Term
Carbenicillin is a ___ + what they're effective against (5)
Definition

Carboxypenicillin

For: g- bacteria including Pseudomonas aeruginosa, enterobacter, morganella, indole-positive proteus, + all those of ampicillin

Term
Ticarcillin is a ___
Definition
Carboxypenicillin
Term
Azlocillin is a ___
Definition
Ureidopenicillin
Term
Mezlocillin is a ___
Definition
Ureidopenicillin
Term
Piperacillin is a ___
Definition
Ureidopenicillin
Term
Ureidopenicillins are effective against ______(6)
Definition

1. all those of carboxypenicillins

2. Klebsiella

3. Serratia

4. Enterobacter

5. Enterococcus

6. Better anaerobic activity

Term
2 penicillins that are acid stable
Definition
Phenoxymethyl penicillin and amoxicillin
Term
Describe the chemical structure of cephalosporins
Definition
B-Lactam ring fused to a dihydrothiazine ring & has a "cephem nucleus"
Term
Describe the MOA of cephalosporins
Definition
They bind to Penicillin-binding proteins (PBP's) in bacterial membranes to prevent them from creating the peptidoglycan cell wall
Term
What are first generation cephalosporins effective against? (4)
Definition

Affective against:

1. Gram + cocci (except enterococci and methicillin-resistant staphylococci)

2. most E. Coli

3. most Proteus mirabilis

4. most Klebsiella.

Term
Cefazolin is a ___ for ___ (2)
Definition
a cephalosporin for perioperioperative prophylaxis for joint protheses or parenteral therapy for simple skin and soft tissue infections
Term
Cefadroxil is a ___ for ___
Definition

a cephalosporin for oral therapy for skin infections or uti's

 

Term
All second generation cephalosporins are more effective (than first generations) against ___ (3), but are less effective against ___
Definition

Effective against:

1. E. coli

2. Klebsiella

3. Proteus

 

Less effective against:

Gram + bacteria

Term
Cefamandole, Cefuroxime, and Cefonicid are ___ with activity against ___
Definition

second generation cephalosporins

 

additional activity against Haemophilus influenzae

Term
Cefoxitin, Cefotetan, and Cefmetazole are ___ with activity against ___
Definition

Are cephamycins (a type of second generation cephalosporins)

 

Additional activity against Bacteroides fragilis

Term
2 Main uses of second generation cephalosporins
Definition

1. Abdominal and pelvic surgery antibiotic
prophylaxis

2. Treatment of mild intra-abdominal
infections (e.g. cholecystitis)

Term

Third generation cephalosporins are most effective against ___ (specific type of microbes)

 

Definition
Best against aerobic gram- bacilli (including H. influenza)
Term
Describe the effectiveness of third generation cephalosporins against gram + microbes.
Definition

poor

 

Except for Ceftriaxone and Cefotaxime against strep. pneumo.

Term
Describe the effectiveness of third generation cephalosporins against anaerobes.
Definition
Variable, includes bacteroides fragilis
Term
Ceftriaxone is a ___ with activity against ___
Definition

A third generation cephalosporin

 

Activity against Streptococcus Pneumoniae ***Penetrates into CSF***

Term
Cefotaxime is a ___ with activity against ___
Definition

Third generation cephalosporin

 

Against streptococcus pneumoniae ***Penetrates into CSF***

Term
Ceftazidime is a ___ with activity against ___
Definition

Third generation cephalosporin

 

Against Pseudomonas aeruginosa ***Penetrates into CSF***

Term
Cefepime is a ___ with activity against ___ (5)
Definition

The only available fourth generation cephalosporin

 

Against:

1. gram +

2. gram - (including pseudomonas aeruginosa)

3. anaerobes

4. multi-resistant gram- bacilli

5. bacteria with B-lactamases

Term
What Cefepime (a fourth generation cephalosporin) is NOT active against
Definition
MRSA
Term
Ceftobiprole is a ___ with activity against ___
Definition

A fourth generation cephalosporin

 

Against MRSA

 

**Not available is United States, but is in some other countries including Canada**

Term

Ceftaroline is a ___ with activity against ___

 

+ it's MOA

Definition

A fifth generation cephalosporin

 

Against MRSA

 

Binds to penicillin-binding protein 2a, in MRSA

Term
Cefamandole is a ___ with activity against ___
Definition

second generation cephalosporin

 

additional activity against Haemophilus influenzae

Term
Cefuroxime is a ___ with activity against ___
Definition

second generation cephalosporin

 

additional activity against Haemophilus influenzae ***Penetrates into CSF***

Term
Cefonicid is a ___ with activity against ___
Definition

second generation cephalosporin

 

additional activity against Haemophilus influenzae

Term
Cefoxitin is a ___ with activity against ___
Definition

A cephamycin (a type of second generation cephalosporins)

 

Additional activity against Bacteroides fragilis

Term
Cefotetan is a ___ with activity against ___
Definition

A cephamycin (a type of second generation cephalosporin)

 

Additional activity against Bacteroides fragilis

Term
Cefmetazole is a ___ with activity against ___
Definition

A cephamycin (a type of second generation cephalosporin)

 

Additional activity against Bacteroides fragilis

Term
Most cephalosporins are excreted by ___. Ceftriaxone, Cefoperazone, and Cefotaxime and excreted by ___.
Definition

Most by kidneys

 

Other 3 by Hepatobiliary

Term
The 2 cephalosporins that have the longest halflives and are therefore good for once a day home IV therapy.
Definition
Ceftriaxone & Cefonocid
Term
Safety & most common side effect of cephalosporins.
Definition

Very safe

 

Most common adverse effect is hypersensitivity: Maculopapular rash after several days of therapy

Term
5 Possible toxicities from cephalosporins and which ones cause which toxicities
Definition

- Nephrotoxicity- interstitial nephritis

- Diarrhea (from hepatobiliary excereted ones)

- Disulfiram-like reaction (can't metabolise alcohol, for ones with a MTT side chain)

- Hypoprothrombinemia (for Cephalosporins with a MTT side chain, competetive inhibition of the MTT group)

- Biliary sludge formation (by Ceftriaxone, because it's excreted in bile and can preicipitate out as crystals in high doses)

 

Term
What are first generation cephalosporins not effective against? (3)
Definition

Not effective against:

1. anaerobes.

2. enterococci (gram + cocci)

3. methicillin-resistant staphylococci (gram + cocci)

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