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24 Cards in this Set

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  • Back

What is an Antibiotic?

Antibiotics are substances produced by living cells that kills or inhibits the growth of microorganisms

What is Broad Spectrum Antibiotics?

It targets both gram + and gram - bacterias

What is Narrow Spectrum Antibiotics?

It targets either gram + or gram - bacterias

What are bacteriostatic drugs? Give examples

It inhibits growth/reproduction of bacteria, allowing the body’s immune system to get rid of the bacteria. e.g. Sulphonamide, Trimethoprim, Tetracycline

What are bactericidal drugs? Give examples

Kills bacteria on it’s own. e.g. Penicillin G, Cephalosporin, Gentamicin

What is selective toxicity and how does it occur?

It is where antimicrobial drugs are more toxic to the microorganism causing infection than to the host cells. This can happen by:

1. Accumulation of a drug

2. Via specific action (Attaching cell walls)

3. A more critical process

How can an allergic reaction occur

Due to repeated exposure leading to sensitivity of various defence mechanism in the body. It is easily treatable however subsequent exposure to the drug can lead to severe or even fatal reactions.

What is a serious side of antibiotics?

Anaphylactic reaction (Penicillin, Cephalosporin) Signs and symptoms: Difficulty breathing, loss of consciousness.

What is cross resistance?

It occurs when one microorganism is resistant to the action of one antimicrobial and shows resistance to others, usually chemically related.

Drug class examples: Beta Lactams

Penicillin and Cephalosporins

Drug class examples: Polymixins

Polymixins B and Colistin

Drug class examples: Rifamycin


Drug class examples: Aminoglycosides

Erythromycin, tetracyclines, Chloramphenicol

Drug class examples: Sulphonamides


What are the 5 antimicrobial drug mechanism of action

1. Inhibition of cell wall synthesis

2. Inhibition of cell wall membrane function

3. Modification of RNA and DNA synthesis

4. Modification of protein synthesis (at ribosome)

5. Modification of energy production in the cystoplasm

Examples of drugs that inhibit cell wall synthesis is:

Penicillin and cephalosporins

Examples of drugs that inhibit cytoplasmic membrane function


Examples of drugs that modifies DNA and RNA synthesis

Rifamprin and Quinolones

Examples of drugs that modifies protein synthesis





Examples of drugs modifying energy production within the cytoplasm

Suphonamide and Trimethropin

What is cross resistance?

It occurs when organisms resistant to the action of one antimicrobial is also resistant to others, usually chemically related.

What is chromosomal resistance?

Spontaneous mutation at a genetic locus on the bacterial chromosomal DNA that control susceptibility to specific drugs.

What is extrachromosomal resistance?

Involves Plasmids (R Factors) that carry genes for resistance to one or more drugs. The plasmids can be transferred between organisms by transduction, transformation, translocation and via bacterial conjugation.

How are bacteria resistant?

1. They produce enzymes that destroys the drug

2. It alters the target required for drugs to work

3. Changes permeability and changes

4. Creates alternative pathways