I seriously doubt you infected the batch, but you may want to put the bottles somewhere safe JUST IN CASE all the sugar wasn't well mixed in. Solid sugar could be more likely to settle, leaving some bottles with more sugar than others.
Not too many years back the method was to drop @ 1/2 tsp of sugar in each bottle & the siphon the newly fermented beer on top prior to capping. I remember helping my dad do that many times--he never had a problem w/ either infection or bottle bombs.