There are many ways of classifying bacteria. One method is based on the cell membrane. In 1884, a bacteriologist named Christian Gram created a test that could determine if a bacterium had a thick, ...

Nine species (240 strains) of gram-negative bacilli were studied; 221 were freshly isolated from the urinary and intestinal tracts, wounds and abscesses. Thirteen strains of salmonella and 6 of ...