抗生素與細(xì)菌耐藥（英文）Bacterial Resistance to Antibiotics

1、Antibiotics & Bacterial Resistance AntibioticsAre natural substances that stops or destroys microorganisms by attacking metabolic pathways in the bacteriaExample penicillin which works by preventing bacteria from constructing a normal cell wallStreptomycin works by preventing bacteria from manufactu

2、ring proteinsThe first antibioticHe noticed a ring of inhibition of bacterial growth around a contaminant blue-green mould on a Staphylococcus plate culture. 1928 discovered by accident Alexander Fleming in St. Marys Hospital, London (UK)He received the Nobel Prize in Medicine in 1945 along with his

3、 two colleaguesHe then concluded that the mould was releasing a substance that was inhibiting bacterial growth and lysing (killing) the bacteria.He grew a pure culture of the mould and discovered that it was a Penicillium mould, now known to be Penicillium chrysogenum. The first antibioticAge of Ant

4、ibioticsSince the 1940s researchers have identified more then 2500 naturally occurring antibiotics that can be used to treat infectionsHowever, over the 50 years since, many disease-causing bacteria have become slowly resistant to the antibioticsAntibiotic resistanceInitially when a antibiotic is in

5、troduced into a system it kills off the weaker strains of bacteriaThis leaves behind the strong strainsThese strong strains have slight variations within their genetic material which allow then to survive the antibioticThese strong bacteria reproduce to pass on their strong fighting abilityAntibioti

6、c use in animals A large percentage of antibiotics produced are used in livestock production in 3 waysTherapeutic doses to treat diseasePreventative doses to reduce risk of disease or death during productionLow dose added to feed to promote growthNon-therapeutic use of antibiotics in farm animals is a good or bad thing?Take 5 minutes and discuss with the person beside you whether its a good or bad thing to add antibiotic to livestock feedThink about pro