Yes, there is a basis or two (and even one for “good luck!”) in Jewish sources for this practice for not blowing out a candle. Any candle. One explanation: The Torah depicts man's soul as being a “breath” from God. The soul is also compared to a flame. Using one’s breath to blow out a candle is an ironic gesture, using one “soul” to extinguish another, so to speak.
Another reason for not blowing out a candle (and for not blowing in general) has been said in the name of Rabbi Yaakov Yisrael Kanievsky, “the Steipler”. There's an angel whose name is the same as the sound produced when one blows out with force. According to Kabbalistic tradition it's improper to make use of the names of holy angels. Many people, therefore, extinguish candles by hand in order not to pronounce the name of this angel.
I know a rabbi who puts out candles by saying the word “Purim”, forcefully emphasizing the letter “P”. And a friend of mine saw his Kung Fu instructor put out a candle by punching it!
Judaism also takes matters of health seriously, even more seriously than matters that concern “prohibition”. “Danger is more serious than (supersedes) prohibition” teach our Talmudic Sages. I once received a letter from a medical doctor who explained why a child shouldn’t blow out the candles on a birthday cake: “Perhaps the most common reason is that parents don't want their children spreading infection by blowing on the cake. More often than not there is more saliva than air expended in the act of blowing out a candle!”
