Antibiotics 1 & 2 Flashcards by Amanda Romeu

Bacteria groups: Aerobic gram-positives

Staph
Streptococcus
Enterococci
Listeria

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Bacteria groups: Aerobic or facultative gram negatives

Enterobacteriacease
Neisseria
Peudomonas
Haemophilus

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Bacteria groups: Anaerobes

Clostridum
Actinomyces
Peptostreptococcus 
Bacteroids
Fusobacterium
Prevotella

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Bacteria groups: Atypical/intracellular

Mycoplasma
Chlamydia
Legionella
Mycobacterium
Rickettsia
Spircochetes

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What bacteriocidals target cell walls?

B-lactams
Vancomycin
Daptomycin (cell membrane)

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What bacteriostatics inhibit growth or replication (RNA synth)?

Rifamycin

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What antibiotics block protein synthesis?

Aminoglycans
Macrolides
Tetracyclins

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What antibiotics target DNA or DNA synth?

Quinolones

Metronidazole

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What is the anti-metabolite antibiotics?

Trimethoprim-sulfamethoxazole

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What are some B-lactams that works on gram positives and some gram negatives?

Penicillins
Cephalosporins
Carbapenems
Monobactams

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What cell wall inhibiting antibiotics are good from gram positives?

Vancomycin

Daptomycin

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What cell wall inhibiting antibiotics are good for TB?

Isoniazid
Ethambutol
Pyrazinaminde

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What is the mechanism of action for B-lactams?

They bind to transpeptidases (PBPs) (which catalyse cross linking of peptidoglycan residues) and block the reaction resulting in weak cell walls

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What kinds of bacteria are natural penicillins active against?

Streptococcal species (GAS, GBS, viridans)
Most gram-positive anaerobes
Treponema pallidum

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What strep group is resistant to natural penicillin?

S. pneomoniae

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What is the action of anti-staph penicillin?

They have large R-groups which make them resistant to staph b-lactamases

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What are some types of anti-staph penicillins?

Nafcilllin, Oxacillin, Dicloxacillin

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What are anti-staph penicillins active against?

MSSA - methicillin sensitive staph aureus

MSSE - methicillin sensitive staph epidermidis

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What are the 2 types of aminopenicillians?

Ampicillin and Amoxicillian

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What does the addition of an amino group to an R chain make aminopenicillins effective against gram-negatives?

Allows for penetration through porins (especially rods)

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Aminopenicillins are effective against many of the same things as natural plus:

E. coli, shigella, salmonella burgdorfi

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What antibiotics are included in the extended spectrum penicillins?

Piperacillin, ticarcillin, carbenicillin

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What can extended spectrum do better than aminopenicillin?

It can better penetrate gram-negative porins

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Extend spectrum penicillins are effective against many of the same things as natural plus:

More enterobacteriaceae and some strains of p. aeruginosa

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What is a beta-lactamase?

Enzymes with specific activity against beta-lactams

What combination can be used as a beta-lactamase inhibitors?

Aminopenicillin and extend spectrum

How does a b-lactamase inhibitor work?

The b-lactam ring acts as a decoy for the lactamases and then IT STRIKES

What bacteria have b-lactamases?

S. aureus, H. influenzae, N, gonorrhoeae, many enterobacteriaceae, certain anaerobes

What antibiotics are b-lactamase inhibitors?

Clavulanic acid Sulbactam Tazobactam

What are some B-lactamases combined with aminopenicillins?

Amoxicillin + Clavulanate = Augmentin | Ampicillin + Sulbactam = Unasyn

What are some B-lactamases combined with extended spectrum penicillins?

Piperacillin + tazobactam = Zosyn | Ticarcilllin + Clavulanate = Timentin

What are some of the problems with the toxins related to penicillins?

Hypersensitivity, can activate a hapten becoming immunogenic after binding to RBC

What signs occur with a type 1 hypersensitivity to penicillin?

Skin rashes and anaphylaxis

What signs occur with a type 2 hypersensitivity to penicillin?

Drug-induced hemolytic anemia

What are some characteristics of Cephalosporins and Cephamycins?

More resistant to b-lactamases than natural penicillins Wider spectum of activity that naturals Generational Not particularly useful against anaerobes or intracellular organisms

What are the first generation Cephalosporins and Cephamycins?

Cefazolin and cephalexin

What is the second generation Cephalosporins and Cephamycins?

Cefuroxime

What is the third generation Cephalosporins and Cephamycins?

Ceftriaxone

What is the fourth generation Cephalosporins and Cephamycins?

Cefepime

What in the "generalization" about Cephalosporins and Cephamycins?

With increaseing generation activity in vitro against aerobic gram-positives decreases while activity against gram-negatives increases

What are the first generation Cephalosporins and Cephamycin used for?

They are similar to aminopenicillin and used for minor skin and soft tissue infections and UTIs

What is the second generation Cephalosporins and Cephamycin used for?

Used against gram-positive spectrum plus acitivty agisnt E. coli, Klebsiella, Proteus, H. influenzae and Neisseria

What is the third generation Cephalosporins and Cephamycin used for?

They are moderately active agisnt aerobic gram positives (MSSA) plus activity against aerobic gram negatives, with modified R chains and can cross through the blood-brain barrier

What is the fourth generation Cephalosporins and Cephamycin used for?

Retains some third generation spectrum, activity against pseudomonas, inc affinity to PBP and can penetrate porins better, poor activity against anaerobes

What are some types of Carbapemems?

Imipenem, meropenem, ertapenem

How do carbapemems rank as a spectrum drug?

Among the most broad spectrum

Compared to other b-lactams, Carbapemems;

Have improved penetration of porins, enhanced binding to PBP and inc resistance to b-lactamases

What are some clinical uses of Carbapemems?

Useful against Pseudomonas

What is special about Imipenem?

It was the "hail mary" of drugs and can be combined with cilastatin (called Primaxin) to inhibit renal dihydropeptidase

What types of bacteria are Carbapenems effective against?

Many bacteria, broad spectrum, useful against Pseudomonas, resistant to B-lactamases

What bacteria are Carbapenems not effective against?

MRSA, Clostridium difficile and Burkholdreia cepacia

Which is the only licensed drug in the Monobactam group?

Aztreonam

Because the R groups are attached directly to the B-lactam ring, what special ability does it have?

Ability to penetrate porins and bind to gram negative PBP

What type of safety situations can Aztreonam be used for?

Used for patients with penicillin allergies and patients with renal disease

Does Aztreonam have what type of spectrum of activity? And which bacteria are effected?

``` Narrow Moraxella Neisseria Enterobacteriaceae Pseudomonas Haemophilus Burkholderia ```

What are some of the adverse reactions to B-lactams?

Penicillin binding to proteins or RBCs to become immunogenic, rashes to anaphylaxis, hemolysis

If someone has adverse reactions to penicillin should they be given cephalosporins?

If a person has a CNS disease what could happen if they were given a Carbapenem?

Seizures

How could a bacteria be resistant to B-lactams?

``` Penetrations (Intracellulars) Porins Pumps (efflux) Penicillinases (B-lactamases) Penicillin-binding proteins Peptidoglycan (lack of) ```

What does it mean when a bacteria is intrinsically resistant to an antibiotic?

The resistance is a constitutive part of the bacterial species - naturally resistant

What is bacterial acquired resistance to a antibiotic?

Resistance formed by mutations, phage transduction and aquiring genes from another bacterial strain/species (transformation, conjugation)

What are some altered cephalosporins and cephamycins and how are they modified?

``` MRSA and Pneumococci (penicillin binding protein) Pseudomas aeruginosa (efflux pump) ```

What does Vancomycin inhibit cell walls?

Binds to the D-ala-D-ala building block of peptidoglycan

With a narrow spectrum of activity, what does Vancomycin work against?

MRSA, penicillin resistant S. pneumo and certain enterococcal infections

How does enterococci make itself resistant to Vancomycin?

Changes the D-ala-D-ala to D-ala-D-lac

When should you use Daptomycin?

For aerbic gram-positives | MRSA, penicillin resistant S. pneumo and vancomycin resistant enterococci

What does Daptomycin not effective against?

Gram negative bacteria