Streptococcus pyogenes is a bacteria that is a member of the streptococci family. It is a gram positive bacteria, which means that it has an extra wall made out of carbohydrates and, as a result, absorbs a special chemical stain known as a gram stain. Streptococcus pyogenes can cause a variety of diseases, most commonly strep throat. Streptococcus pyogenes infections often need to be correctly identified before antibiotics are prescribed.
Step 1
Recognize the symptoms of a Streptococcus pyogenes infection. Streptococcus pyogenes can cause strep throat (painful red throat accompanied by white spots on the tonsils), impetigo (red crusty sores commonly found on the face), cellulitis (red, swollen, very painful skin) and toxic shock (pain, swelling, redness, and a sudden drop in blood pressure).
Step 2
Culture the bacteria. The most common reason Streptococcus pyogenes would need to be identified is if strep throat is suspected. To culture Streptococcus pyogenes from the throat, rub a cotton swab against the tonsils to extract some of the bacteria. Spread the bacteria across a petri dish filled with agar. After seventy-two hours, examine the petri dish to check for colonies of bacteria.
Step 3
Examine the bacteria under a microscope. Streptococcus pyogenes will appear round under a microscope and will commonly be seen forming small chains of bacteria.
Step 4
Test for beta-hemolysis. When Streptococcus pyogenes are cultured on a special growth media known as blood agar (which is bright red), they will demonstrate beta-hemolysis, which means that the area around the bacteria will become clear.
Step 5
Do a serologic test. Place a small portion of a bacterial culture into a test tube along with special chemicals. The presence of Streptococcus pyogenes will cause cloudiness to appear in a clear solution.
Things You'll Need
- Cotton swab
- Petri dish with agar
- Petri dish with blood agar
- Microscope
- Glass slide
- Test tube
- Serologic test reagents
