Bacteria may have a very distinctive appearance when viewed on a Gram stained smear. Distinct characteristics are not as evident on direct smears as they are on Gram stains of colonies and/or stains from broth cultures, but these shapes can be identified on direct smears.
- Cocci: Round or oval
- Bacilli: Rod-shaped
Gram-positive cocci (GPC):
- Singly and in clusters (May indicate staphylococci)
- In pairs and chains (May indicate streptococci)
GPC can be seen in clusters and chains in Image 1 below.
Image 1. Gram-positive cocci in clusters and chains.