Last updated on June 11th, 2021
Staphylococcus and Streptococcus are the two most common pathogenic gram-positive cocci of medical importance. They share some of the important properties.
Common characteristics shared by these gram-positive cocci are:
- Nonmotile,
- Non-Sporing,
- Facultative anaerobes
| Characteristic | Staphyloccus | Streptococcus |
| Shape | Gram-positive cocci in clusters (grape-like) because cell division occurs in various directions on multiple axes. Gram-positive cocci in pairs, tetrads, short chains also seen. | Gram-positive cocci in pairs or short chains (Cell division occurs in single-axis) |
| Catalase Test (Most Important test to differentiate Staph from Strep) | Positive (presence of catalase enzyme) | Negative |
| Growth Requirement | Not fastidious (does not need enriched media) | Fastidious (needs enriched media). |
| Hemolysis | No hemolysis or beta hemolysis | Either alpha or beta or gamma hemolysis (hemolysis can be helpful to differentiate species of Streptococcus) |
| Common habitat | Mostly skin, anterior nares | Mainly mouth and respiratory tract |
| Common diseases | Pneumonia, meningitis, osteomyelitis, acute endocarditis, septic arthritis, surgical site infection, wound infection, etc. | Pneumonia, sore throat, wound infection, necrotizing fasciitis, scarlet fever, rheumatic fever, acute post-streptococcal glomerulonephritis |
| Most pathogenic species | Staphylococcus aureus Staphyloccus saprophyticus (in female) | Streptoccus pneumoniae Streptoccus pyogens Streptococcus agalactiae |
| Useful diagnostic tests | Catalase Test Coagulase Test Novobiocin sensitivity test | Catalase Test Bacitracin Sensitivity Test (S. pyogens) Optochin Sensitivity Test (S. pneumoniae) Bile solubility Test (S. pneumoniae) CAMPT Test (S. agalactiae) |
