Staphylococcus vs. Streptococcus

Gram positive cocci in clusters
Staphylococcus in Gram Stain

Last updated on June 11th, 2021

Streptococcus spp   (S. pyogenes and S. pneumoniae)
Streptococcus spp (S. pyogenes and S. pneumoniae)

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
ShapeGram-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 RequirementNot fastidious (does not need enriched media)Fastidious (needs enriched media).
HemolysisNo hemolysis or beta hemolysisEither alpha or beta or gamma hemolysis (hemolysis can be helpful to differentiate species of Streptococcus)
Common habitatMostly skin, anterior naresMainly mouth and respiratory tract
Common diseasesPneumonia, 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 speciesStaphylococcus aureus
Staphyloccus saprophyticus (in female)
Streptoccus pneumoniae
Streptoccus pyogens
Streptococcus agalactiae
Useful diagnostic testsCatalase 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)
About Acharya Tankeshwar 476 Articles
Hello, thank you for visiting my blog. I am Tankeshwar Acharya. Blogging is my passion. I am working as an Asst. Professor and Microbiologist at Department of Microbiology and Immunology, Patan Academy of Health Sciences, Nepal. If you want me to write about any posts that you found confusing/difficult, please mention in the comments below.


  1. this good but i want to ask you this question in the butt of a TSI gas production is evidenced by want?

  2. Thanks so much it was a great short and very good overview exactly what I was searching

  3. Test result of a wound culture:


    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).

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