From Politico:
Most analysts interviewed for this story said they do not expect Israel to be invited to the meeting, but they expect it to enter into the discussions one way or the other.
[Obama]
However, a former deputy national security adviser in Israel, Chuck Freilich, said the benefits to Israel of any U.S.-led meeting on nuclear security were likely to outweigh the costs.
Some of the nuclear issues related to Israel could bubble up as soon as next month. Susan Rice, the U.S. ambassador to the United Nations, announced last week that Obama plans to convene U.N. Security Council heads of state on September 24 to talk about nuclear proliferation issues.
Israel could face unwanted attention at that meeting, since Libya is among the countries currently on the council.