Evolution In Action The Case of the Super Bacteria

A Bad Moon Rising According to the U.S. Centers for Disease Control (“CDC”), the emergence and re- emergence of infectious disease organisms contributed to a 58% increase in U.S. per capita mortality from infectious diseases between 1980 and The incidence of drug-resistant infections is reaching crisis levels in many hospitals, in part because antibiotic resistant organisms frequently lurk in the hospital setting.

The Enemy: Bacteria E. coli Current location: –Your stomach –Some nasty spinach in Salinas

What is an antibiotic resistant bacteria? A bacteria with proteins that can protect them from the deadly effects of antibiotics Basically the bacteria have genes that give them some measure of immunity They survive where others are destroyed

So what’s an antibiotic? The overwhelming majority of antibiotic substances are natural products that certain bacteria and fungi (molds) produce and send outside of their cells. About 90% of the antibiotics in use today, are isolated from bacteria.

How do antibiotics work? Penicillins: Inhibits formation of the bacterial cell wall by blocking cross- linking of the cell wall structure. The cell wall is a needed protective casing for the bacterial cell Tetracyclines: Inhibit protein synthesis by binding to the subunit of the bacterial ribosome (30S subunit).

Testing for Effectiveness Doesn’t Work Kills ‘em good

How do bacteria resist antibiotics?

How do bacteria become resistant? 1.A mutation of their own 2.Inheriting the trait from a predecessor 3.Acquiring a plasmid from another bacteria 4.Endocytosis of free DNA 5.Injection of resistant gene by bacteriophage virus

Why are bacteria changing so rapidly? 1.We use antibiotics too often, increasing the selection pressure in favor of resistance 2.Improper us of antibiotics (we don’t take them as the doctor orders, allows the strongest to survive) 3.No new class of antibiotics in 20 years (they keep changing but we don’t) 4.Hospitals