I never heard that before. It was not a factor in the two cases I know of.
And what tests to perform if candida is suspected in blood?
I read in Wikipedia that systematic candida also can be caused due to stress, how accurate is that?
We all harbor candida in our bodies to a lesser or greater extent. Overgrowth in the mouth can create a condition called thrush. (Can you find out if your friend had thrush?) Systemic candidiasis is more rare and more problematic. I doubt that you can "catch" systemic candidiasis in the normal sense of that word. But if you are concerned, or show signs of candidiasis, please see your doctor.