2. What does the doctor look for on the slide?
In addition to color, which indicates whether the organism is Gram positive or Gram negative, the shape of the organism (such as rod-shaped) and the formation of groups of organisms are informative. For example, staphylococcus (staph) bacteria are found in grape-like clusters, while streptococcus (strep) bacteria are found in pairs or chains, like a string of pearls.
3. What happens if my doctor needs more information than the Gram stain provides?
The Gram stain is usually done in conjunction with a culture. This allows for more exact identification of the bacteria causing the infection and determination of the most appropriate antibiotic.
