I've noticed that when I'm doing four quadrant streaking of plates and I sterilize my loop between each quadrant, I normally get barely any growth beyond the first quadrant- maybe one or two isolated colonies in the second quadrant. Additionally when I don't sterilize between each quadrant, I usually have isolated colonies by the fourth quadrant.

If I'm obtaining isolated colonies, is there any issue with not sterilizing between quadrants? Why might I be getting this result?