One Poisoned Bottle, Binary Testers

You have 1000 bottles of wine, exactly one of which is poisoned. A tester who drinks any amount containing the poison dies after exactly the same fixed delay, and you can have each tester sip from any combination of bottles simultaneously in a single round (results observed after the delay, before the celebration). If you only get ONE round of testing, what is the minimum number of testers needed to guarantee identifying the poisoned bottle?