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29 Cards in this Set
- Front
- Back
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Antimicrobial drugs
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Interfere with the growth of microbes within a host
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Antibiotic
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Substance produced by a microbe that in small amounts inhibits another microbe
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Fleming
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1928
Discovered penicillin |
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Florey and Chain
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1940
First clinical trials of penicillin |
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Gram Positive Rods
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Bacillus subtilis
Paenibacillus polymyxa |
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Fungi
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Cephalosporium spp.
Penicillium griseofulvum Penicillium chrysogenum |
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Antinomycetes
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Streptomyces nodosus
Streptomycems venezuelae Streptomyces aureofaciens Saccharopolyspora erythraea Streptomyces fradiae Streptomyces grisues Micromonospora purpurea |
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4 Features of Antimicrobial Drugs
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Selective toxicity
Antimicrobial action Spectrum of Activity Adverse Effects |
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Selective toxicity
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Cause greater harm to microorganism than to human host (interfere with microorganism processes but not human ones)
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Antimicrobial Action
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Bacteriostatic vs. Bacteriocidal
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Spectrum of Activity
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Broad Spectrum: inhibit a wide range of bacteria
Narrow-spectrum: limited range |
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Adverse Effects (3 Things)
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Allergic reactions
Toxic effects (negative harms to the body) Suppression of Normal Flora: broad spectrum antibiotics kill normal bacteria which allow other bacteria to grow that normally wouldn't be able to (Clostridium difficile) |
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Targets of Antibacterial Drugs (5)
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Cell Wall Synthesis
Protein Synthesis Nucleic acid synthesis Metabolic Pathways Cell membrane integrity |
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What is the main drug that inhibits cell wall synthesis?
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Penicillin
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Natural Penicillin
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Penicillin G, V
narrow-spectrum antibiotics (Gram positive, some Gram negative) |
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Semisynthetic penicillins
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Extended-spectrum penicillins
Resistant to Penicillinase/B-Lactamase |
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Extended-spectrum penicillins
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Greater activity against Pseudomonas species, Gram negative bacteria
Less active against Gram-positive bacteria Destroyed by B-lactamase |
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2 examples of Extended-spectrum penicllins
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Ticarcillin
Piperacillin |
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Oxacillin
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Narrow spectrum
Only Gram positives Resistant to penicillinase |
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Ampicillin
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Extended spectrum
Gram- Negative |
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Protein Synthesis Antibiotics (3)
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Chloramphenicol
Streptomycin Tetracyclines |
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Chloramphenicol
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Binds to tRNA and inhibits the peptide bond
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Streptomycin
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Changes shape of smaller portion (30s) ribosome and causes mRNA code to be read incorrectly
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Tetracyclines
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Interferes with attachment of tRNA to mRNA-ribosome complex
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Where are antibiotic resistant genes typically located?
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On plasmids or transposons
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4 Mechanisms for Resistance against Antibiotics
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Blocking entry
Inactivating enzymes Alteration of target molecule Efflux of antibiotic |
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Selective Advantage to resistant Bacteria
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Once all the non-resistant bacteria are killed off by anitbiotics, the only bacteria that remain are the resistant kind and they may therefore multiple with no competition for resources
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5 Ways to Misuse Antibiotics that lead to Resistance
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Outdated/weakened antibiotics
Using incorrect antibiotics for that certain bacteria Antibiotics in animal feed Not completing the prescribed regimen Using someone else's leftover prescription |
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4 Examples of Emerging Resistant Bacteria
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Enterococci (vancomycin resistant)
Staphylococcus aureus (methicillin resistant) Streptococcus pneumoniae (penicllin resistant) Mycobacterium tuberculosis |
