Most species of bacteria can be broadly divided into two groups, known as gram-positive and gram-negative. These categories reflect big differences in the microbes' biology, and they also dictate how ...

One hundred and twenty-six strains of gram-positive and gram-negative micro-organisms — staphylococci (40), streptococci (16), enterococci (10), Diplococcus pneumoniae (4), Corynebacterium ...