evidence: There are 2 main types of germs that cause most infections. These are viruses and bacteria. [...] Some viruses cause symptoms that resemble bacterial infections, and some bacteria can cause symptoms that resemble viral infections. Your healthcare provider can determine what type of illness you have and recommend the proper type of treatment. [...] Talk with your healthcare provider about antibiotics and find out about the differences between viruses and bacteria, and when antibiotics should and should not be used.