High Genetic Variability
High abundance: Several million cells in a spoon of soil or a milliliter of water; 6 billion/cheese sandwich
Fast growth: 20-30 min generation time
Random mutation: 1:106; with 5,000 genes in E. coli, one out of 200 cells should carry one mutation
Genetic Recombination: exchange of genes by viruses or through conjugation
Antibiotic resistance -- once resistance genes have been acquired, they are rapidly spread in the population
“Germ killers” and “anti-microbial soap” might lead to inability to fight human diseases