d6 antibacterials

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D6 Antibacterials. Historical development of penicillin How penicillin works Patient compliance Overprescription. Bacteria. Bacteria are single cells with a protective cell-wall made up of complex structures of Peptidoglucans They have a single chromosome- a plasmid - PowerPoint PPT Presentation



D6 AntibacterialsHistorical development of penicillinHow penicillin worksPatient complianceOverprescription

BacteriaBacteria are single cells with a protective cell-wall made up of complex structures of Peptidoglucans

They have a single chromosome- a plasmidAnaerobic (no need of oxygen) or aerobic (need oxygen)Some cause diseases, others are beneficialAntibacterial are chemicals that prevent growth and multiplication of bacteria

Early antibacterialsTrypan red, developed by the german chemist Paul Erlich (1854-1915) to cure sleeping sicknessArsenamine, Salvarsan, was developed to cure syphilis. Paul Erlich responsibleProntosil, a sulpha drug, used against streptococcal bacteria (1935)Penicillin (1928)!Fleming 1928Worked with Staphylococcus aureusLeft petri dish when he went on holidayDiscovered on comeback that it had mouldedThe mould produced a substance that inhibited growth of the bacteriaHe called the substance penicillin, but didnt pursue his discovery

http://www.youtube.com/watch?v=7qeZLLhx5kUFlorey and Chain 1941Learned how to isolate and purify penicillinUsed penicillin on policemen who was dying from septicaemia (blood poisoning)The structure of penicillin was determined in 1950s- chemists could start synthesising it!Fleming, Florey and Chain recieved the Noble Prize in 1945

How penicillin worksInterferes with the enzyme that build the cell-wall (which animal cells dont have)The weakened cell-wall disintegrates while the bacterium grows, and it diesBacteria can become resistant by producing an enzyme called penicillinase, which deactivates the penicillin

Benzylpencillin- has to be injectedModifications of penicillin side chainBeta-lactam-ring

Benzylpencillin potassium salt- more water soluble and less acidic

Piperacillin- broad spectrum antibiotic

Fluocloxacillin- is beta-lactamase stable

Amoxillin- better absorbed, used orally

Prescription of antibioticsIts important to eat the whole cure of penicillin and to take it reguarlyTo not give the antibiotics to someone elseSpecific bacteria crave different penicillinsBroad- and narrow-spectra penicillinCombination of drugs can be used

Dangers with over-prescriptionResistant bacteriaKill the good bacteriaBacteria becomes immune- by mutationPrecribed although not neededMRSA-bacteriaMetillicin- Resistant Staphylococcus AureusThe super bugMakes beta-lactamase which degrades penicillin



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