The main difference between streak plate and pour plate is that in streak plate, the first to be added is the melted nutrient agar and the second to be added is a loop of bacteria from a slant, whereas the first to be added in pour plate is the bacterial broth and the second to be added is the nutrient agar. Furthermore, the volume of inoculum in the streak plate is only a loopful from a bacterial slant while the volume of inoculum in pour plate is 1.0 to 0.1 mL. Moreover, streak plate is for the isolation of colonies while the pour plate is for counting the number of colonies. Show
Streak plate and pour plate are two techniques in microbiology to grow mainly bacteria and fungi in Petri dishes with nutrient agar. Key Areas Covered1. What is Streak Plate Key TermsBacterial Broth, Colony Counting, Isolation of Colonies, Nutrient Agar, Pour Plate, Streak Plate What is Streak PlateStreak plate is the technique in microbiology to isolate pure strain from a single species of microorganisms. Moreover, the resulting colonies can be further studied through isolation. However, the main importance of this technique is to dilute a comparatively large concentration to a smaller concentration. Generally, the inoculation loop is the main equipment for streaking. Usually, the sterile inoculation loop is dipped in the inoculation of microorganisms and then is dragged across the surface of the agar back and forth in a zigzag motion. When 30% of the surface area is covered, the plate is turned 90 degrees. Moreover, the inoculation loop has to be sterilized. Then, the streaking continues, starting from the previous section in the zigzag motion, until it covers all the surfaces of the plate is the T-streak method. What is Pour PlatePour plate is another technique in microbiology important for counting the number of colony-forming bacteria in a liquid specimen. Generally, in this method, around 1 mL of the liquid broth is placed on the sterile Petri dish using a pipette. Then, pouring the melted nutrient agar and well-mixing is the second step. Furthermore, in the pour plate, microorganisms grow on the surface as well as within the medium. However, the faster growth of colonies occurs on the surface. Each colony represents a colony-forming unit. Therefore, we can use their counting to determine the number of microorganisms in the sample by the following formula. CFU/mL= CFU * dilution factor * 1/aliquot Similarities Between Streak Plate and Pour Plate
Difference Between Streak Plate and Pour PlateDefinitionStreak plate refers to a rapid qualitative isolation method for obtaining discrete colonies from a mixed population while pour plate refers to the method of choice for counting the number of colony-forming bacteria present in a liquid specimen. Thus, this explains the fundamental difference between the streak plate and pour plate. First to AddThe first thing we add in a streak plate is the melted nutrient agar, while the first thing we add in a pour plate is the bacterial broth. Second to AddIn contrast to the above, the second thing we add to the streak plate is a loopful of bacteria from a slant, while the second thing we add to the pour plate is the melted nutrient agar. The Volume of the InoculumThe volume of inoculum in the streak plate is only a loopful from a bacterial slant while the volume of inoculum in pour plate is 1.0 to 0.1 mL. PurposeAnother major difference between the streak plate and pour plate is that streak plate is for the isolation of colonies while the pour plate is for counting the number of colonies. EquipmentStreak plate method requires a Petri dish, alcohol lamp, and a wire loop while the pour plate method requires a Petri dish, alcohol lamp, pipet, test tubes, and a glass rod. Type of ColoniesStreak plate produces surface colonies while the pour plate produces both surface and subsurface colonies. AdvantagesMoreover, streak plate is important for the isolation of bacterial cultures by preparing distinct colonies while the pour plate is important for the quantification of colonies in a solid medium. DisadvantagesThe main disadvantage of streak plate is the higher probability of contamination while the main disadvantage of pour plate is microbes have to withstand the temperature of the melted nutrient broth during preparation. ConclusionStreak plate is a technique in microbiology used to isolate colonies from a culture. In this technique, a loopful from the bacterial slant is systematically streaked on a nutrient broth. Therefore, it produces surface colonies. Also, this method is important to isolate pure species from a mixture. On the other hand, pour plate is another technique in microbiology used to count colonies. Here, the sample of bacteria is suspended in a Petri dish using melted nutrient agar. Therefore, it produces both surface and subsurface colonies. Moreover, it is important to quantify the colony-forming bacteria. However, the main difference between streak plate and pour plate is the method and importance. References:1. “Streaking (Microbiology).” Wikipedia, Wikimedia Foundation, 28 May 2019, Available Here. Image Courtesy:1. “Legionella Plate 01” By CDC/James Gathany – CDC Public Health Image Library (ID#: 7925) (Public Domain)via Commons Wikimedia
Aim: To perform the Streak plate method. Principle:It is a common method used to separate and isolate a particular bacterial colony from a mixture of bacteria. In the streak plate method, the concentration of bacterial colonies is more at the starting point and it goes on decrease toward the last point of the streak. It helps to isolate individual colonies from other colonies and each colony is considered a pure colony. Requirement:
General Procedure:
Three Sector Streak (t- streak):
Four Quadrant Streak method:
Observation: Examine the growth of isolated colonies on the surface of the nutrient agar plate. Result: Few numbers of isolated colonies appear along with the points of the streak. Advantages:
Disadvantage:
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