The main difference between streptococcus pyogenes and streptococcus agalactiae is that streptococcus pyogenes is bacitracin sensitive, whereas streptococcus agalactiae is bacitracin resistant.
S. pyogenes and S. agalactiae are two types of beta-hemolytic organisms. They are also Gram-positive bacteria that are cocci.
Key Areas Covered
1. What is Streptococcus Pyogenes
– Definition, Features, Importance
2. What is Streptococcus Agalactiae
– Definition, Features, Importance
3. Similarities Between Streptococcus Pyogenes and Streptococcus Agalactiae
– Outline of Common Features
4. Difference Between Streptococcus Pyogenes and Streptococcus Agalactiae
– Comparison of Key Differences
Key Terms
Streptococcus Agalactiae, Streptococcus Pyogenes
What is Streptococcus Pyogenes
Streptococcus pyogenes is a species of Gram-positive bacterium that belongs to the genus Streptococcus. It is also a non-sporing, non-motile coccus bacterium. In addition, it tends to form chains. Generally, S. pyogenes is a part of the skin microbiota. S. pyogenes is important to humans as a pathogenic bacterium. Normally, it causes Group A Streptococcal infection and is classified as Group A Streptococci according to the Rebecca Lancefield classification of streptococci. It is a predominant species of harboring Group A antigen.
Figure 1: S. pyogenes
Furthermore, the colonization of S. pyogenes typically occurs in the skin, throat, genital mucosa, and rectum. Generally, there are four methods of transmission in the S. pyogenes infection. They include skin contact, contact with objects, inhalation of respiratory droplets, and through food. This bacterium can cause a number of illnesses, such as streptococcal pharyngitis, rheumatic heart disease, rheumatic fever, and scarlet fever. Apart from that, S. pyogenes produces small zones of beta-hemolysis when grown on blood agar. Usually, the size of the zones is around 2-3 mm. The culturing of S. pyogenes also occurs in fresh blood agar plates.
What is Streptococcus Agalactiae
Streptococcus agalactiae is another species of Gram-positive bacterium that has a round shape. It also shows a tendency to form chains. Additionally, S. agalactiae is a beta-hemolytic bacterium that is catalase-negative and facultative anaerobic. A bacterial capsule surrounds the S. agalactiae cell. In general, polysaccharides make up the bacterial capsule. S. agalactiae is a group B of the Rebecca Lancefield classification as it contains group B antigen.
Figure 2: S. agalactiae
Moreover, Group B Streptococci are harmless bacteria that are a part of the human microbiota. Generally, they colonize in the gastrointestinal and genitourinary tract. However, they cause severe invasive infections in newborns, elder people, and people with compromised immune systems. In addition to that, S. agalactiae is a common pathogen in animals, causing bovine mastitis. S. agalactiae also produces a number of virulent factors that boost the capacity of the bacterium to infect and damage human tissues.
Similarities Between Streptococcus Pyogenes and Streptococcus Agalactiae
- S. pyogenes and S. agalactiae are two types of Gram-positive cocci.
- Both show tendency to chains.
- They are beta-hemolytic bacteria that are catalase negative.
- Both are virulent bacteria.
Difference Between Streptococcus Pyogenes and Streptococcus Agalactiae
Definition
Streptococcus pyogenes refers to a genus of Gram-positive, aerotolerant bacteria in the genus Streptococcus, while Streptococcus agalactiae refers to a Gram-positive coccus with a tendency to form chains.
Also Known As
S. pyogenes is bacitracin sensitive, while S. agalactiae is bacitracin resistant.
Microbiota
S. pyogenes occurs in skin microbiota, while S. agalactiae occurs in the gastrointestinal and genitourinary tract.
Rebecca Lancefield Classification
S. pyogenes belongs to Group A Streptococcus, while S. agalactiae belongs to Group B Streptococcus.
Conclusion
In brief, S. pyogenes and S. agalactiae are two types of Gram-positive bacteria. They are cocci bacteria that are beta-hemolytic and catalase negative. In addition, both are catalase-negative bacteria. Usually, S. pyogenes is bacitracin sensitive, and it occurs in skin microbiota. In comparison, S. agalactiae is bacitracin resistant and occurs in the gastrointestinal and genitourinary tract. Generally, S. pyogenes belongs to Group A Streptococcus while S. agalactiae belongs to Group B Streptococcus. Overall, the main difference between S. pyogenes and S. agalactiae is the type of antigen present in each bacterium.
References:
- Patterson MJ. Streptococcus. In: Baron S, editor. Medical Microbiology. 4th edition. Galveston (TX): University of Texas Medical Branch at Galveston; 1996. Chapter 13.
Image Courtesy:
- “Streptococcus pyogenes” By Quibik – Own work (Public Domain) via Commons Wikimedia
- “Streptococcus agalactiae on Granada medium” By 43trevenque – Own Work (CC BY-SA 4.0) via Commons Wikimedia
Leave a Reply