First you need to make a personal choice: Do you want to leave your current employer, or not?
If you have no desire to leave simply tell the recruiters (politely!) that you are sorry, but you recently came to work for a new employer, you are happy where you are, and you are not currently looking to change employment.
Make sure to be polite - You may decide later on that you do want to interview with this other company, and you don't want to burn your bridges.
If you do want to leave your current employer, respond as you would to any interview request when you're seeking employment (schedule an interview, talk to them, get an offer, etc.) -- Be aware however that a history of serial short-term employment may not look great on a resume.