Thank you for the opportunity to help you with your question!
You can be contaminated by all sorts of things, chemicals, virus's, bacterias. An infection is when your body comes in contact w/ something may it be bacteria or virus's and for whatever reason is unable to fight it off. You get symptoms of an infection. Some infections just run their course & don't need any treatment (virus's), some you may just need over the counter antibiotic ointment & to keep a cut or burn clean. Other types of infections: respiratory, wound, urinary tract, etc, etc, may need antibiotics. Some infections are very tough to cure, we are increasingly seeing them in the hospital for no apparent reason and we need stronger medication & a longer time to cure them. These certain types are called antibiotic resistant infections, they take a long time to cure and are transmitable to others who are caring for them or have chronic health problems, are young or have depressed immune systems. Sometimes these individuals can be cured of the acute symptoms of a wound or respiratory or gastrointestinal antibiotic resistant infection, but remain what we call colonized. It means that if a culture were taken of certain places on their body it would continue to come back positive for that organism. They are no longer acutely ill but their body is colonized will that organism.
Please let me know if you need any clarification. I'm always happy to answer your questions.