✨
BLACK FRIDAY SALE ✨ SAVE UP TO 45% OFF NOW
Medicine (MD/DO)
/
Courses
/
Microbiology
/
Gram Positive Cocci
/
Streptococcus pyogenes Characteristics

Master Streptococcus Pyogenes Characteristics

Master Streptococcus pyogenes with Picmonic! Our engaging characters, stories, and mnemonics make learning fun and interactive. Watch this video to remember key characteristics and its Gram stain.

DOWNLOAD PDF
Streptococcus pyogenes Characteristics

Streptococcus pyogenes Characteristics

Stripper Pie-genie
Picmonic
Streptococcus pyogenes is a gram-positive cocci that causes group A streptococcal infections. Strep pyogenes typically produces large zones of beta hemolysis, and can be distinguished from other streptococcal organisms because it is catalase-negative and bacitracin-sensitive. Diseases caused by Streptococcus pyogenes include skin infections like impetigo, cellulitis, pharyngitis, scarlet fever and toxic shock-like syndrome. Streptococcus pyogenes infections can also precipitate episodes of rheumatic fever and acute glomerulonephritis.
12 KEY FACTS
CHARACTERISTICS
Group A Streptococci (GAS)
A-Apples

Group A Streptococci, commonly referred to as GAS, are infections caused by the bacterium Streptococcus pyogenes. Diseases caused by Streptococcus pyogenes infections include skin conditions such as impetigo and cellulitis, as well as pharyngitis, scarlet fever, and toxic shock-like syndrome. S. pyogenes infections can also lead to episodes of rheumatic fever and acute glomerulonephritis.

Gram-Positive
Graham-cracker Positive-angel

This organism stains positive on a Gram stain due to its thick peptidoglycan layer, which absorbs crystal violet.

Cocci
Cockeyed

This bacterium has a spherical shape and appears on a histological slide as cocci arranged in chains.

Beta-Hemolytic
Beta-fish in Petri-dish

S. pyogenes typically causes large zones of beta hemolysis, which is the complete lysis of red blood cells in the culture media. Streptolysin O, an exotoxin produced by the bacteria, causes complete lysis of red blood cells by interacting with the cholesterol membrane.

Catalase-Negative
Negative-cat

Characteristically, S. pyogenes is catalase-negative, which helps distinguish it from Staphylococcal species that are catalase-positive.

Bacitracin-Sensitive
Bass Sensitive-crying

Bacitracin can be used to differentiate Streptococcus pyogenes from other beta-hemolytic Streptococci, such as Streptococcus agalactiae. Streptococcus pyogenes is bacitracin-sensitive, whereas Streptococcus agalactiae is resistant.

Hyaluronic Acid Capsule
Hay Capsule

Many strains of Streptococcus pyogenes have a hyaluronic acid capsule, which aids this organism in resisting phagocytosis. Another defensive factor against phagocytosis is M protein.

Streptolysin O
Stripper with O Earrings

Streptolysin O is an oxygen-labile exotoxin that S. pyogenes releases. It is often tested for using an ASO, or antistreptolysin O titer.

DNase
DNA Lace

Streptococcus pyogenes produces DNase, an enzyme that cleaves the DNA backbone, degrading DNA. This allows the organism to infect pharyngeal tissues and skin, while also degrading the DNA of neutrophil extracellular traps, which would normally kill these bacteria.

Streptokinase
Stripper with Kite-ace

Streptokinase is an enzyme that inhibits the coagulation cascade in humans. S. pyogenes produces this enzyme, causing blood clots to dissolve, enabling the bacteria to spread easily throughout the body.

Exotoxin A
Exploding Apples

Exotoxin A produced by S. pyogenes aids in virulence by decreasing the production of antibodies and potentiating the likelihood for necrotizing fasciitis and streptococcal toxic shock syndrome. The expression is highly variable among different strains of this bacteria.

Pyrrolidonyl Arylamidase (PYR) Positive
Positive Pyro

The pyrrolidonyl arylamidase (PYR) test is a rapid test, which has largely replaced the bacitracin test. Streptococcus pyogenes is a positive control, and is well known to be positive for PYR, which can be tested for in 10-15 minutes.

DOWNLOAD PDF

Recommended Picmonics

picmonic thumbnail
Streptococcus Pyogenes Disease
picmonic thumbnail
Staphylococcus aureus Characteristics
picmonic thumbnail
Staphylococcus aureus Disease
picmonic thumbnail
Staphylococcus saprophyticus
picmonic thumbnail
Staphylococcus epidermidis

Take the Streptococcus pyogenes Characteristics Quiz

Picmonic's rapid review multiple-choice quiz allows you to assess your knowledge.

Why Med Students Love Picmonic

Our Story Mnemonics Increase Mastery and Retention

Memorize facts with phonetic mnemonics

Unforgettable characters with concise but impactful videos (2-4 min each)

Memorize facts with phonetic mnemonics

Ace Your Medicine (MD/DO) Classes & Exams with Picmonic:

Over 1,980,000 students use Picmonic’s picture mnemonics to improve knowledge, retention, and exam performance.

Choose the #1 Medicine (MD/DO) student study app.

Picmonic for Medicine (MD/DO) covers information that is relevant to your entire Medicine (MD/DO) education. Whether you’re studying for your classes or getting ready to conquer the USMLE Step 1, USMLE Step 2 CK, COMLEX Level 1, or COMLEX Level 2, we’re here to help.

Works better than traditional Medicine (MD/DO) flashcards.

Research shows that students who use Picmonic see a 331% improvement in memory retention and a 50% improvement in test scores.