- Slides: 16
Antibiotic Resistant Bacteria: Natural Selection at Work
Bacteria are everywhere • Bacteria are single-celled organisms • Many different kinds of bacteria can grow together in similar environments • Millions of different bacteria live on and inside of you! Pictures taken with an electron microscope
Serratia marcescens • Grow in damp places – – Bathrooms Soil Biofilm on teeth Digestive tract • As a human pathogen, can be associated with urinary tract and wound infections • What’s a pathogen?
What are antibiotics? • Powerful medicines that treat bacterial infections - Do NOT work on viruses! WHY? Think “Anti-Bio”… Kills living things… Are viruses alive? • Antibiotics kill bacteria
How do bacteria become resistant? • A mutation in the DNA of the bacteria makes it resistant the harmful effects of the antibiotic – So, it cannot be killed by the medicine – If the bacteria is not destroyed… What will it do? ? ? • Genes for resistance can appear spontaneously (genetic mutation) – This can happen with insects as well!
Natural Antibiotic Resistance • Mutations that allow bacteria to resist the effects of antibiotics already exist in the bacterial population • Not all bacterial cells within a population are identical • Like a population of humans, they all contain slight differences in their DNA (variation) Why do you think this may be a good idea for the bacteria? -Survival of the Fittest
Can the misuse of antibiotics result in resistant bacteria? • Antibiotics are prescribed by doctors to fight bacterial infections • Antibiotics do not treat viral infections! • How do doctors know what to prescribe? – throat, urine cultures • Why is it important to finish your prescription?
Tuberculosis • TB affects your lungs and coughing is often the only sign of infection until it’s too late – Yes… you can die from TB • In the US, TB declined in the 1950 s mainly because of antibiotics • TB is re-emerging • World Health Organization indicates that rates of tuberculosis resistant to multiple drugs (MDR-TB) are now at their highest level ever Mycobacterium tuberculosis TB lung infection
What are some potential problems because of antibiotic resistant bacteria? • MRSA – What is MRSA – The Truth about Methicillin-resistant Staphylococcus aureus
Good Bacteria? YES! • Our bodies provide a home for many kinds of good (and necessary) bacteria! – In our gut – In our mouth – On our skin Bacteria in the mouth Pimple caused by bacteria
How can we prevent bacterial growth? • We try to prevent the growth of some bacteria on our bodies and in our homes • What are some common products you use on a regular basis for cleaning? – – – Soaps (hand soap, face wash) Toothpaste/mouthwash Dish soap Laundry detergent Mops and sponges • Most if not all contain a chemical to prevent bacterial growth
99. 9%. . • Antibacterial soaps, hand sanitizers, household cleaners and Listerine state that they kill 99. 9% of bacteria – What about the remaining 0. 1%? • Remember… If you survive… you feed and breed? • What does that mean? ? – The 0. 1% of bacteria that are not affected by the cleaners will reproduce… – Creating an entire generation of bacteria which are resistant to sanitizers!
Are we causing the evolution of resistant bacteria with the use of antibacterial products? • Long term exposure to chemicals allows the bacteria that contain genes for resistance to survive and reproduce at a rapid rate! • What do you think? • Should antibacterial products be used in such a common way?
The Same Happens With Insects
Remember… • VARIATION (diversity) ensures that a species will survive… – Remember “Contagion”! • The MORE VARIATIONS in a species (ANY species… from humans to daffodils to amoebas to mosquitoes to dalmations…) the greater the chance of survival! – More genetic diversity ensures the species will continue to exist!