Strep throat, the most common form of Streptococcus pyogenes! I bet you've had it at least once.
Blood agar plate of Streptococcus pyogenes, by Dr. William Schwan, University of Wisconsin-La Crosse.
When you go in to see the doctor and they take a throat culture, they put the contents of the swab on a blood agar plate, just like the one above. The appearance of this plate is from a special technique, streak plate method, which is used to isolate colonies of bacteria. At the end of the blue arrow, you can see a colony of the Streptococcus pyogenes. The white circular area around the bacteria is the beta hemolysis. Beta hemolysis is seen as a complete clearing of the blood agar medium around the colonies. The white area around the colony is the clearing from the Streptococcus pyogenes.
This bacteria causes a ton of problems!
Streptococcus pyogenes is solely a pathogen of humans and is carried asymptomatically usually in the throat by 20-25% of the population (Hart 88). It is spread person to person by respiratory droplets or by physical contact. Penicillin is used as the treatment and unfortunately there is no vaccine available. Fortunately, Streptococcus pyogenes is very sensitive to penicillin and have not become resistant or formed any antibiotic resistant mutants (O'Leary 103-104).
Streptococcus pyogenes is one of the most common pathogens of soft tissue infections (Hawkey and Lewis 147-148). The most frequent upper respiratory tract disease is a type of pharyngitis called strep throat, which is caused by Streptococcus pyogenes (Sankaran 234). With repeated attacks of streptococcal sore throat a person can experience an increase in damage to their heart valves.
Information on this page is from Starr, Mortimer P (The Prokaryotes), Hart, Tony (Microterrors), O'Leary, William (Practical Handbook of Microbiology), Hawkey, Peter, Deirdre Lewis (Medical Bacteriology), and Sankaran, Neeraja (Microbes and People).