This post was most recently updated on August 26th, 2019
Staphylococcus and Streptococcus are two most common pathogenic gram positive cocci of medical importance. They share some of the important properties.
Common characteristics shared by of these gram positive cocci are:
- Non motile,
- Non Sporing,
- Facultative anaerobes
| Characteristic | Staphyloccus | Streptococcus |
| Shape | Gram positive cocci in clusters (grape-like) becausecell 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 fascitis, 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 TestBacitracin Sensitivity Test (S. pyogens) Optochin Sensitivity Test (S. pneumoniae) Bile solubility Test (S. pneumoniae) CAMPT Test (S. agalactiae) |
this good but i want to ask you this question in the butt of a TSI gas production is evidenced by want?
Thanks so much it was a great short and very good overview exactly what I was searching
Test result of a wound culture:
MANY STREPTOCOCCI, ALPHA HEMOLYTIC
MANY STAPHYLOCOCCUS SPECIES, NOT AUREUS
What does this mean? I got this on a Friday and the Dr is out until Monday. Thank you.
Hello Eric, Streptococcus genus contains both beta-hemolytic and alpha hemolytic species. S. pyogenes and S.agalactiae are beta-hemolytic but S.pneumoniae and viridans streptococci (common name for various Streptococci species that gives alpha hemolysis) are alpha hemolytic. In Staphylococci, S.aureus is the pathogenic one but S. epidermidis, S. saprophyticus are mostly commensal (normal flora) and occasionally be pathogenic. So common phrase Coagulase Negative Staphylococci (CONS) is used for them; (S. aureus is coagulase positive).