Which of the following is essential for the development of discrete, isolated colonies in microbiology?

• A. Use of liquid broth media
• B. Incubation at high temperature
• C. Addition of antibiotics to the medium
• D. Streak plate technique

Answer: (D)

Verified step by step guidance

1. Understand that discrete, isolated colonies are formed when individual microbial cells are separated on a solid growth medium so that each cell can grow into a visible colony.
2. Recognize that liquid broth media do not allow for the physical separation of individual cells, so they cannot produce isolated colonies.
3. Know that incubation temperature affects growth rate but does not inherently cause isolation of colonies.
4. Realize that adding antibiotics to the medium can select for resistant organisms but does not by itself create isolated colonies.
5. Identify that the streak plate technique is a method used to physically spread cells on a solid agar surface to separate them, enabling the development of discrete, isolated colonies.