Staphylococcus vs. Streptococcus

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 important properties.

Common characteristics shared by these gram-positive cocci are:

  • Nonmotile,
  • Non-sporing,
  • Facultative anaerobes

Some of the major differences between Staphylococcus and Streptococcus are summarized in the table below.

Characteristic Staphylococcus Streptococcus
ShapeGram-positive cocci in clusters (grape-like) because cell division occurs in various directions on multiple axes. Gram-positive cocci in pairs, tetrads, and short chains are also seen.Streptococci are either Gram-positive cocci in pairs (S. pneumoniae) or short chains (S. pyogenes). This is because the cell division occurs on a single axis.
Catalase Test (Most Important test to differentiate Staph from Strep)Staphylococci are catalase-positive (presence of catalase enzyme)Streptococci are catalase negative
Growth RequirementStaphylococci are not fastidious (does not need enriched media)Streptococci are fastidious (need enriched media); so they cant grow in nutrient agar and need blood agar for growth.
HemolysisStaphylococci give no hemolysis or beta hemolysis. Species of Streptococci are able to show any types of hemolysis (alpha or beta or gamma hemolysis). Hemolysis is a helpful tool to differentiate species of Streptococcus
Common habitatStaphylococci are commensal of skin and anterior nares Streptococci are found mainly in the mouth and respiratory tract as a commensal
Common diseasesStaphylococci mostly cause wound infections. Other diseases caused by this organism are osteomyelitis, acute endocarditis, septic arthritis, surgical site infection, interstitial pneumonia, etc.Pathogenic species of streptococci cause pneumonia, meningitis, sore throat, wound infection, necrotizing fasciitis, scarlet fever, rheumatic fever, acute post-streptococcal glomerulonephritis
Most pathogenic speciesStaphylococcus aureus
Staphyloccus saprophyticus (in females for causing UTI)
Streptoccus pneumoniae
Streptoccus pyogenes
Streptococcus agalactiae
Useful diagnostic testsCatalase test
Coagulase test
Novobiocin sensitivity test
Catalase test
Bacitracin sensitivity test (S. pyogenes)
Optochin sensitivity test (S. pneumoniae)
Bile solubility test (S. pneumoniae)
CAMP test (S. agalactiae)

Acharya Tankeshwar

Hello, thank you for visiting my blog. I am Tankeshwar Acharya. Blogging is my passion. As an asst. professor, I am teaching microbiology and immunology to medical and nursing students at PAHS, Nepal. I have been working as a microbiologist at Patan hospital for more than 10 years.

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