What do I do about derogatory information from a former employer?

I was working for a school for students with disabilities. After observing the support staff physically and mentally abuse the students the first week...I made a report with CPS the second week. By the third week I was terminated for "misconduct." Do I have to include this on a resume or job application. I went to an interview today and didn't mention it but the potential employer brought it up and asked what happened. He then told me that he was told that I was terminated for a physical altercation with another employee which is not true at all. They are trying to retaliate because of the report I made. Can anything be done since they are slandering my name? I am a teacher and my reputation is on the line. I have a legal obligation to report suspected abuse and that is what I did. On top of all of this, someone at this facility let the air out of my tires and my unemployment was denied.