Selection of Bacteria
Chosen on basis of morphology and reaction to Gram stain
Bacillus subtilis: gram+ bacillus, found in soil or dust
Staphylococcus epidermidis: gram+ coccus, common on skin
Escherichia coli: gram - bacillus, found in human intestine
Serratia marcescens: gram - bacillus, found in soil, water and some nosocomial infections