How to decline an interview

So I recently applied to a new graduate position in my home town. The position was assisting in an administrative role in a long term care facility, conducting quality assurance, research and developing education sessions. This is the type of work I am pursuing and one of the reasons I am pursuing a MSN in September. It is only a few days before the closing date so I contacted the individuals who's name was on the posting (DOC's) to ensure she received my application. She did, however was confused when I discussed the job description as she stated it was a regular staff floor nurse position... when I pointed out the job description and her error she emailed me back told me the posting had been made before she became DOC (Obviously not true since she has been the DOC there for over 2 years and posted the description last week), changed it and asked if I would still be interested. However I am not interested as I was not looking for a floor nursing position. Regarding bedside care I have been with an organization for over four years who offered me a bedside position paying competitively once I graduated, however bedside care was not the direction I planned my career to go. Although I appreciate the experience it can bring it would not be my first choice. I now have to inform the DOC I am not interested in pursuing an interview for the position, as if I am unable to find a job, my organization (which I am still with) will give me full time RN work. Does anyone know of a good way to say thank you but no longer interested at this time, without burning bridges? Jobs are rare in my town so if something goes wrong and the position with my current company doesn't work out and at the LTC facility comes up in the future and catches my eye I would still like to be able to be considered.

Thank you for any advice!