Unseen by our eyes every day many micro organisms enter our body and try to set up colonies in our tissues. Bacteria, fungi and viruses are the common microorganisms that try to invades our body but our own body's defence mechanism prevent this invasion and colonization. When the defences fail, there is an infection. Infections are a frequent cause of minor illnesses like colds, coughs, fever, diarrheas, etc but some infections can be severe and devastating. Most of these infections can be eradicated with the use of antibiotics.