If your doctor told you that you have trep throat, you could conclude that you are infected with which type of pathogen?

The answer is Group A Streptococcus bacteria.
 It is a bacterium often found in the throat and on the skin. People may carry group A streptococci in the throat or on the skin and have no symptoms of illness. Most GAS infections are relatively mild illnesses such as "strep throat," or impetigo. On rare occasions, these bacteria can cause other severe and even life-threatening diseases

The answer is joseph is observing the colour of the reaction mixture to see whether proteins are present in the given solution.