What is the Difference Between Staphylococcus Aureus and Streptococcus Pyogenes

The main difference between Staphylococcus aureus and Streptococcus pyogenes is that Staphylococcus aureus causes localized diseases such as abscess formation and purulent discharge. In contrast, Streptococcus pyogenes causes extensive diseases ranging from erysipelas to necrotizing fasciitis.

S. aureus and S. pyogenes are two types of disease-causing bacteria. Both types are Gram-positive, cocci-shaped, non-motile, non-spore-forming, facultative anaerobes.

Key Areas Covered

1. What is Staphylococcus Aureus
   • Definition, Characteristics, Importance
2. What is Streptococcus Pyogenes
   • Definition, Characteristics, Importance
3. Similarities Between Staphylococcus Aureus and Streptococcus Pyogenes
   • Outline of Common Features
4. Difference Between Staphylococcus Aureus and Streptococcus Pyogenes
   • Comparison of Key Differences

Key Terms

Staphylococcus Aureus, Streptococcus Pyogenes

What is Staphylococcus Aureus

Staphylococcus aureus is a major human bacterial pathogen that causes a wide variety of diseases. Infections of S. aureus are common both in community-acquired as well as hospital-acquired settings and treatment remains challenging to manage due to the emergence of multi-drug resistant strains such as MRSA (Methicillin-Resistant Staphylococcus aureus). In addition, S. aureus occurs in the environment and also occurs in normal human flora, located on the skin and mucous membranes (most often the nasal area) of most healthy individuals. Normally, S. aureus does not cause infection on healthy skin; however, if it enters the bloodstream or internal tissues, these bacteria may cause a variety of potentially serious infections. Transmission is typically from direct contact. However, some infections involve other transmission methods.

Figure 1: Staphylococcus aureus

Furthermore, S. aureus commonly occurs in the upper respiratory tract and in the skin. Therefore, it is commensal in the human microbiota. However, it may become an opportunistic pathogen, being a common cause of skin infections including abscesses, respiratory infections such as sinusitis, and food poisoning.  

What is Streptococcus Pyogenes

Streptococcus pyogenes is a major human-specific bacterial pathogen that causes a wide array of manifestations ranging from mild localized infections to life-threatening invasive infections. Ineffective treatment of S. pyogenes infections can also result in postinfectious sequela acute rheumatic fever and post-streptococcal glomerulonephritis. Moreover, it causes invasive infections like necrotizing fasciitis and toxic shock syndrome, which are associated with high morbidity and mortality.

Figure 2: Streptococcus pyogenes

Moreover, Streptococci are gram-positive and catalase-negative cocci that occur in pairs or chains. They are divided into three groups by the type of hemolysis on blood agar: alpha-hemolytic (green hemolysis), beta-hemolytic (complete lysis of red cells), and gamma-hemolytic (no hemolysis). Beta-hemolytic streptococci are characterized as group A streptococci (Streptococcus pyogenes) and group B streptococci (Streptococcus agalactiae). Usually, group A streptococcal infections originate from the pathogenic skin microbiota. In addition, group A Streptococci harbors the Lancefield group A antigen.

Similarities Between Staphylococcus Aureus and Streptococcus Pyogenes

• S. aureus and S. pyogenes are two disease-causing bacteria types.
• Both types are Gram-positive, cocci-shaped, non-motile, non-spore-forming, facultative anaerobes.

Difference Between Staphylococcus Aureus and Streptococcus Pyogenes

Definition

S. aureus refers to a type of bacteria found on human skin, in the nose, armpit, groin, and other areas, while S. pyogenes refers to a species of gram-positive, coccoid bacteria isolated from skin lesions, blood, inflammatory exudates, and the upper respiratory tract of humans.

Division

S. aureus has a multiple axes cell division and forms grape-like clusters while S. pyogenes single axes cell division and forms a chain of round cells.

Catalase Test

S. aureus is catalase test positive while S. pyogenes is catalase test negative.

Enriched Media

S. aureus is not fastidious and does not require enriched media while S. pyogenes is fastidious and requires enriched media.

Growth

Moreover, S. aureus occurs in the skin while S. pyogenes occurs in the respiratory tract.

Hemolysis

S. aureus does not undergo hemolysis while S. pyogenes undergoes either alpha, beta, or gamma hemolysis.

Common Diseases

S. aureus causes food poisoning, bacterial conjunctivitis, skin diseases, community-acquired meningitis, surgical site infection, wound infection, impetigo, cellulitis, and toxic shock syndrome, while S. pyogenes causes strep throat, scarlet fever, impetigo, toxic shock syndrome, cellulitis and necrotizing fasciitis (flesh-eating disease), sinusitis, blood infections, pneumonia and meningitis in newborns.

Conclusion

In brief, S. aureus and S. pyogenes are two disease-causing bacteria. Both types of bacteria are Gram-positive, cocci-shaped, non-motile bacteria. S. aureus occurs in the skin while S. pyogenes occurs in the respiratory tract. Usually, S aureus causes food poisoning, bacterial conjunctivitis, skin diseases, community-acquired meningitis, surgical site infection, wound infection, impetigo, cellulitis, and toxic shock syndrome. Whereas, S. pyogenes causes strep throat, scarlet fever, impetigo, toxic shock syndrome, cellulitis and necrotizing fasciitis (flesh-eating disease), sinusitis, blood infections, pneumonia, and meningitis in newborns. Therefore, the main difference between S. aureus and S. pyogenes is the type of diseases they cause.

References:

1. Taylor TA, Unakal CG. Staphylococcus Aureus. [Updated 2022 Jul 18]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-.
2. Kanwal S, Vaitla P. Streptococcus Pyogenes. [Updated 2022 Feb 24]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. 

Image Courtesy:

1. “Staphylococcus aureus Gram” By Y Tambe– Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Streptococcus pyogenes” By Quibik – Own Work (Public Domain) via Commons Wikimedia