Streptococcus “Strep” VS Staphylococcus “Staph”: How do they differ?

Streptococcus (above) Vs. Staphylococcus (bottom)

There are a lot of similarities between Streptococcus (Strep) and Staphylococcus (Staph) that lead to confusion. Both are:

  1. spherical, facultatively anaerobic gram-positive bacteria
  2. common members of the normal human microbiota
  3. capable of resisting many forms of important antibiotics
  4. some species are capable of being pathogenic, responsible for serious infections and even deaths directly or indirectly through virulence factors such as toxins

The key differentiating characteristics between these two groups of bacteria are:

  1. their formation and cell division e.g. division occurs on a single axis growing in pairs or chains (Strep)  vs division in various directions on multiple axes (Staph) growing in grape-like clusters
  2. their ability to produce catalase (enzyme to break down hydrogen peroxide) e.g. Strep is catalase negative vs Staph is catalase positive
  3. their need for enriched media for growth (e.g. Strep needs enriched media (fastidious) vs Staph does not need enriched media (not fastidious))
  4. most staphylococci are found on the skin whereas most streptococci are found in the respiratory tract.

When Streptococcus is seen dividing through a microscope, it is shaped spherically,  remaining attached and growing in beadlike pairs or chains. Many species of Streptococcus are common and do not cause any human disease. This bacterium is commonly found in the throat but doesn’t always show any symptoms that indicate a disease. Some species under certain conditions, can cause infections.

The type of infections you can get from Streptococcus pyogenes are rheumatic fever (inflammatory disease that effects the heart, joints, skin and brain), impetigo (skin infection), scarlet fever, puerperal fever, streptococcal toxic shock syndrome, strep throat, tonsillitis, and other upper respiratory infections. Some symptoms of Streptococcus include: fever, sore throat and swollen lymph nodes, red & weeping skin sores, rash,  dizziness and confusion.

Under a microscope, Staphylococcus looks like a bunch of grapes or little round berries often found in clusters or pairs (image above). These bacteria are most often found on the skin or in the mucus membranes of healthy people and can remain there without signs of infection. Under certain circumstances, such as wounds, cuts, or in-dwelling catheters, Staphylococcus can become pathogenic. The types of infections one can get from this type of bacteria are bacteraemia (blood infection), osteomyelitis (bone infection), endocarditis (infection of the inner lining of the heart and valves), abscesses in internal organs such as lungs, pneumonia and toxic shock syndrome.

Staph infections can look like a pimple and can be red, swollen and tender. The area can be warm to touch and can have pus that needs to be drained. If the infection gets into the blood, symptoms will include fever, chills and low blood pressure.

In the past, it was less important to determine the underlying source of infection. However with rising antibiotic resistance, it is becoming more important to determine the source of infection or even potential source of infection to quickly and effectively prescribe the appropriate treatment and preventative measures.



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6 Responses to “Streptococcus “Strep” VS Staphylococcus “Staph”: How do they differ?”

  1. Jennifer Norsen says:

    My daughter had a puncture wound in her thumb that blistered.
    It was treated and the pus was tested for staph and strep, both came back positive. She is only 6, and I don’t know where to start to find out what is wrong.Can you offer any suggestions. I am scared to death that her immune system is compromised.

  2. Hi Jennifer,

    Staph and strep would be typical contaminants of a puncture wound. This would have nothing to do with her immune system. In the vast majority of cases the body can easily fight these bugs and resolve the issue. The problem comes in those rare cases where the body is unable to fight off the infection and where antibiotics likewise do not help. If the injury is improving and is not worsening then most likely there is nothing to worry about.

    Wishing your daughter a speedy recovery.

    Roger A., MD

  3. S says:

    I recently developed a lip infection (outside the mouth) after having a mucocele removed (3 stitches on inner side of lower lip). For two days or so before the removal, I noticed that my lips felt sort of chapped, and burned a little despite using copious amounts of chapstick. Within an hour of the minor surgery, not only was my lower lip swollen (to be expected obviously) but my upper lip started to swell a little, and the chapped/burning sensation continued. The next morning I woke up to ubiquitous red, blotchy, lips with small bumps here and there (not concentrated patches, but more distributed), which eventually became crusty (yellowish), with new ones popping up periodically. I assumed it was HSV, despite never having cold sores in my life before, but when I went to a clinic, they said it was a 50/50 chance of HSV or Staph/Strep (they couldn’t take a culture). Is there any visual way to distinguish between a staph/strep infection vs. an HSV infection? Also, I’ve been washing my hands 1000 times a day, especially before and after I touch my lips, but are there other precautions I should be taking? Should I be disinfecting every surface daily? I’m usually not one to be so germophobic, but I’m paranoid about spreading it (regardless of what it is) to anyone else, especially my partner.

  4. mvuyisi says:

    actually that might be opotunistic infection maybe by the time you were stitched the evironment was not properly hygenic. so the organism that might cause those pains it might be staiphiloccus aereous as it some times the normal flora of the skin.

  5. kate says:

    my daughter had maternal strep b after 10 days of antibiotics on the intensive care unit she was fine, now 7 weeks old she has develouped a blistering rash on her bottom which could be a staph infection.. is there any link between the two as we were told she could be re-infected with strep b up untill 12 weeks old..

  6. Hello, all is going nicely here and ofcourse every one is sharing information, that’s truly fine, keep up writing.

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