Pour plate and streaking technique to obtain pure cultures

1. Discuss the relative convenience of pour- and streak-plate techniques in culturing clinical specimens. 2. How do you decide which colonies should be picked from a plate culture of a mixed flora? 3. Why is it necessary to make pure subcultures of organisms grown from clinical specimens? 4. What kinds of clinical specimens may yield a mixed flora in bacterial cultures? 5. When more than one colony type appears in pure culture, what are the most likely sources of extraneous contamination?