The process involving the culture, isolation, and identification of microorganisms is basic to medical microbiology. When a culture shows signs of growth, the process of identification includes examining the following characteristics:
- Appearance of the colonies in the culture medium
- Staining reaction
- Appearance of stained organisms, including the:
- Arrangement of bacterial cells
Based on the colony characteristics, the Gram stained smear can provide additional information to further confirm initial impressions and guide the microbiologist towards identification. This type of preliminary identification may help the physician to initiate the appropriate antibiotic treatment. As much preliminary information should be provided to the physician as possible.