Bacterial Evoluation and Antibiotic Resistance

Antibiotics are powerful medicines that fight bacterial infection Literal translation anti – against biotic – living things

Discovery Alexander Fleming in 1928 He was an extremely messy scientist Came back from holiday to see discover mold growing on his Staphylococcus agar plates Noticed that the Staphylococcus couldn’t grow anywhere near the mold The mold prevented bacterial growth!

How antibiotics work Antibiotics can be either: Broad Spectrum Kill a wide range of bacteria Ex: Penicillin Narrow Spectrum Kill a specific type or group of bacteria Ex: Isoniazid – treat TB Antibiotics work in one of two ways: Bactericidal Kills the bacteria itself Bacteriostatic Prevents the bacteria from dividing

Miracle Cure? Before the 1930’s: there were no treatments for bacterial infections Following the discovery of penicillin: the industry started searching for more antibiotics in nature Streptomycin: 1st drug to have an effect on tuberculosis – a condition previously untreatable Advantage: surgeons could attempt more dangerous operations

Overuse of antibiotics can damage our normal/good bacteria. Miracle Cure? Overuse of antibiotics can damage our normal/good bacteria. Many antibiotics prescribed by the doctor are broad spectrum These kill the body’s good bacteria as well as the bad With the good bacteria gone there is more room for bad microbes to invade!

Antibiotics Resistance Miracle Cure? Antibiotics Resistance Many bacteria have developed the ability to become resistant to antibiotics. These bacteria are now a major threat in our hospitals. Antibiotic resistant bacteria include Methicillin Resistant Staphylococcus Aureus (MRSA) Video

Antibiotics Need Time to Work Day 1 R Antibiotics Need Time to Work Day 5 R X Antibiotics prescribed Day 10 R X Infection cured! Antibiotics also need time to do their work! Medication taken for full course of treatment

Incomplete Treatment Causes Resistance Day 0 R Antibiotics prescribed R X Day 3 Symptoms improved, treatment stopped R Day 10 Resistant infection Meanwhile, the survivors multiply. Quitting treatment too early only kills the susceptible (“weak”) bacteria, leaving the resistant (“strong”) ones to multiply.

Antibiotic Resistance The Causes Overuse Antibiotics used to treat infections when they are not needed or not effective Ex: for the flu Misuse Not completing a prescribed course Using antibiotics not prescribed for you

How antibiotic resistance can be prevented Antibiotics should be the last line of defense NOT the first Most common infections will get better by themselves through time, bed rest, liquid intake and healthy living. Only take antibiotics prescribed by a doctor If prescribed antibiotics, finish the course. Do not use other peoples or leftover antibiotics They be specific for some other infection