Two patients checked into the hospital with similar symptoms of lower respiratory diseases. Doctors determined that one patient had influenza and the other had pneumonia. Both patients think that they need antibiotics, but the doctors only give antibiotics to one patient. Why were antibiotics only prescribed for one of these patients? Pneumonia is caused by bacteria, which can be killed by antibiotics; influenza is caused by a virus, which cannot be killed by antibiotics. Influenza is caused by a bacteria and needs to be treated with antitussives, but pneumonia is caused by a virus and can be treated with antibiotics. Influenza and pneumonia are both caused by viruses, so antibiotics would only work for the patient with a stronger immune system. Influenza and pneumonia are both caused by bacteria, but the bacteria that causes pneumonia cannot be killed by antibiotics.