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Staphylococcus vs. Streptococcus: What's the Difference?

Edited by Aimie Carlson || By Harlon Moss || Updated on October 28, 2023
Staphylococcus and Streptococcus are both gram-positive bacteria, but while Staphylococcus tends to form clusters, Streptococcus forms chains. They cause different sets of infections in humans.

Key Differences

Staphylococcus is a genus of bacteria known for its round shape and the tendency to form clusters that resemble grapes. It's a versatile bacterium that can thrive in a range of environments, including the human skin. Streptococcus, on the other hand, is also a round-shaped bacterium, but it typically arranges itself in chains. This bacteria frequently inhabits the throat and skin.
Many strains of Staphylococcus are harmless, but some, like Staphylococcus aureus, can cause skin infections, respiratory diseases, and food poisoning. Streptococcus, in contrast, can lead to various illnesses. For instance, Streptococcus pyogenes causes strep throat and skin infections, while Streptococcus pneumoniae leads to pneumonia.
Staphylococcus has garnered attention in the medical world due to MRSA (Methicillin-Resistant Staphylococcus aureus), which is a type resistant to many antibiotics. Streptococcus, in its spectrum of diseases, can lead to scarlet fever, rheumatic fever, and impetigo, highlighting the need for its timely identification and treatment.
Both Staphylococcus and Streptococcus play pivotal roles in human health and disease. While Staphylococcus is often associated with hospital-acquired infections, Streptococcus is commonly linked to community-acquired illnesses. Proper diagnosis and treatment are crucial for infections caused by these bacteria to prevent complications.

Comparison Chart


Round and forms clusters
Round and forms chains

Common Diseases

Skin infections, respiratory diseases, food poisoning
Strep throat, pneumonia, scarlet fever

Notable Strains

Staphylococcus aureus, MRSA
Streptococcus pyogenes, Streptococcus pneumoniae


MRSA is notably resistant to many antibiotics
Some strains show antibiotic resistance


Commonly on skin and mucous membranes
Throat, skin, and some mucous membranes

Staphylococcus and Streptococcus Definitions


A gram-positive, round-shaped bacterium.
The sample tested positive for gram-positive cocci, indicating possible staphylococcus presence.


A gram-positive bacterium linked to various human diseases.
Streptococcus pneumoniae is a major cause of community-acquired pneumonia.


A cause of various human infections, including skin conditions.
The wound was infected with staphylococcus, leading to an abscess.


Found in various habitats, including the human throat and skin.
Streptococcus is part of the normal flora of some individuals.


A bacterium that forms clusters resembling grapes.
Under the microscope, the staphylococcus culture showed characteristic clusters.


Can lead to complications like rheumatic fever if untreated.
The untreated streptococcus infection progressed to rheumatic fever.


Commonly found on human skin and mucous membranes.
Healthy skin often harbors staphylococcus without causing infections.


A common cause of throat infections, known as strep throat.
The child was diagnosed with strep throat caused by streptococcus.


Known for certain antibiotic-resistant strains like MRSA.
The patient was infected with MRSA, a resistant form of staphylococcus.


A bacterium that typically forms chains of round cells.
The throat swab showed chains of cocci, suggesting a streptococcus infection.


Any of various spherical gram-positive parasitic bacteria of the genus Staphylococcus that usually occur in grapelike clusters and commonly cause skin infections such as cellulitis and impetigo and other infectious conditions and diseases.


What is Staphylococcus?

Staphylococcus is a genus of bacteria that forms clusters and can cause various infections.

Are all Streptococcus infections serious?

While many Streptococcus infections are mild, some can be serious or even life-threatening.

Which is more common in hospital settings: Staphylococcus or Streptococcus?

Staphylococcus, especially MRSA, is more commonly associated with hospital-acquired infections.

How can Staphylococcus infections be treated?

Most Staphylococcus infections are treated with antibiotics, but some strains are resistant.

Can Staphylococcus cause food poisoning?

Yes, some strains of Staphylococcus release toxins causing food poisoning.

Which is more resistant to antibiotics: Staphylococcus or Streptococcus?

Both can have resistant strains, but MRSA (a Staphylococcus strain) is notably antibiotic-resistant.

What diseases does Streptococcus cause?

Streptococcus can cause diseases like strep throat, pneumonia, and scarlet fever.

How is Streptococcus transmitted?

Streptococcus can be transmitted through respiratory droplets or direct contact.

Is Streptococcus part of the normal human flora?

Yes, some Streptococcus species are part of the normal human flora, especially in the throat.

How can one differentiate between Staphylococcus and Streptococcus in a lab?

Apart from their shape and arrangement, specific biochemical tests can differentiate between the two.

How is Staphylococcus transmitted?

Staphylococcus can be transmitted through direct contact, contaminated surfaces, or food.

Is MRSA a type of Staphylococcus?

Yes, MRSA is a methicillin-resistant strain of Staphylococcus aureus.

Can Streptococcus infections lead to complications?

Yes, untreated Streptococcus infections can lead to complications like rheumatic fever.

What precautions can reduce the risk of Staphylococcus infections?

Regular handwashing and wound care can reduce the risk of Staphylococcus infections.

Can Staphylococcus cause respiratory infections?

Yes, Staphylococcus can cause respiratory infections like pneumonia.

Are Staphylococcus and Streptococcus gram-positive?

Yes, both Staphylococcus and Streptococcus are gram-positive bacteria.

Is strep throat the only illness caused by Streptococcus?

No, Streptococcus can cause various illnesses, including skin infections and pneumonia.

What's the difference in the appearance of Staphylococcus and Streptococcus under a microscope?

Staphylococcus forms clusters, while Streptococcus forms chains.

Is Staphylococcus found on healthy skin?

Yes, Staphylococcus can be part of the normal flora on healthy skin.

Are Staphylococcus infections contagious?

Many Staphylococcus infections, especially skin infections, are contagious.
About Author
Written by
Harlon Moss
Harlon is a seasoned quality moderator and accomplished content writer for Difference Wiki. An alumnus of the prestigious University of California, he earned his degree in Computer Science. Leveraging his academic background, Harlon brings a meticulous and informed perspective to his work, ensuring content accuracy and excellence.
Edited by
Aimie Carlson
Aimie Carlson, holding a master's degree in English literature, is a fervent English language enthusiast. She lends her writing talents to Difference Wiki, a prominent website that specializes in comparisons, offering readers insightful analyses that both captivate and inform.

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