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How to make a streak plate?
What are streak plates used for?
What is the goal of streak plate technique?
Feb 21, 2024 · Written by Acharya Tankeshwar in General Microbiology Last Updated February 21, 2024. For organisms that grow well on agar plates, a streak plate is the method of choice for obtaining pure culture. The streak plate technique is used to isolate the organisms (mostly bacteria) from a mixed population into a pure culture.
- What Is Streak Plate Method?
- Objectives of Streak Plate Method
- Principle of Streak Plate Method
- Types of Streak Plate Method
- Procedure Or Protocol of Streak Plate Method
- Result Interpretation of Streak Plate Method
- Precautions During Streak Plate Method
- Applications of Streak Plate Method
- Advantages of Streak Plate Method
- Limitations of Streak Plate Method
The streak plate method is a microbiological laboratory technique of isolating pure cultures, and/or getting well-isolated colonies of bacteria from a mixed population. It is mostly used to get pure cultures of bacteria; however, yeasts can also be isolated by this method. It is one of the most commonly used aseptic techniques in microbiology to is...
To obtain a pure culture of bacteria from a mixed cultureTo obtain well-isolated coloniesTo propagate bacteriaThe streak plate method is based on dilution during the process of mechanical spreading of inoculum over the surface of solidified culture media in order to obtain well-isolated colonies of the sample at the terminal streaks. Sample can be either colony on solid media or suspension in broth. The sample is picked by using different tools, mostly usi...
Based on the pattern of streaking, the streak plate method can be classified into 4 types, viz.: Quadrant Streaking, T-Streaking, Continuous Streaking, and Radiant Streaking.
The general procedure of the streak plate method can be summarized as: 1. Arrange all the requirements, put on the PPE, sterilize the work surface, and allow all the samples and media to come to room temperature if were refrigerated. 2. If the sample is very concentrated then dilution can be helpful to get the isolated colonies. (But it is not comp...
Results can be interpreted after the incubation period (mostly 24 hours at 370C). Following incubation, the terminal streaks are observed for isolated colonies. Morphologies of the isolated colonie...In the first area of streaking, there is heavy growth with fused colonies, and gradually there are fewer colonies in subsequent streaks giving a few well-isolated colonies in the final streak.Colonies with similar appearances are expected in pure culture.If the sample contained single species then colonies with similar morphologies are obtained. But, in the case of mixed culture, colonies with different morphologies are obtained.Media should be properly solidified before use. If it is refrigerated, allow it to come to room temperature.Check for the presence of water droplets and/or any contamination or foreign substance in media prior to streaking.Follow proper safety protocols. Treat every unknown or clinical specimen as hazardous and follow safety accordingly.If using a toothpick for streaking, use the blunt end by holding the pointed end between your thumb and ring finger at an angle of 10 to 200to the medium. Dispose it after streaking each quadrant a...Used to obtain a pure culture from the mixed culture in order to perform morphological, biochemical, and molecular tests to identify and for other applications.Used to define the specimen as pure or mixed species.Used to study colony characters of bacteria.Used to produce a colony of genetically identical individualsIt is a simple, reliable, convenient, and easy-to-perform method of inoculation.It results in well-isolated colonies, each of genetically identical individuals; hence, we can perform further tests and applications on the isolates. Hence, it is followed in clinical diagnosis.Dilution is done along with the process of inoculation (or streaking), hence, no need to perform separate dilution of the sample.Allow manually to control the sample and sample size and the inoculating area in a petri dish.It is a qualitative isolation method, so don’t help in quantifying the microbial load.It is more suitable for aerobic organisms rather than anaerobes.Syntrophic bacteria can’t be purified by this method.It is unsuitable if the sample size is large and has a very high viable count. If we take heavy inoculum there may not be isolated colonies following the incubation.Pelczar and Reid (8) presented a streak plate exercise. It utilized a 4-quadrant streak pattern, and the procedure described using both a loop and a needle in the streak and all streaks were in the same direction, rather than both back and forth. FIG. 2. A drawing representing the streak pattern recommended by Pelczar and Reid (8).
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A streak plate involves the progressive dilution of an inoculum of bacteria or yeast over the surface of solidified agar medium in a Petri dish. The result is that some of the colonies on the plate grow well separated from each other. The aim of the procedure is to obtain single isolated pure colonies.
The streak plate is a common technique used to produce pure cultures from a mixed sample. The goal of the streak plate is to spread individual microorganisms so far apart on the surface of solid medium that they do not touch one another.
Dec 24, 2022 · Spread plates are simply microbes spread on a media plate. Microbes are in a solution, and can be diluted. They are then transferred to a petri dish with media specific for the growth of the microbe of interest.
The quadrant streak plate reduces or dilutes the number of cells using successive streaking zones on the petri plate and flaming the inoculation loop between zones. The petri plate is divided into four sections or zones. Bacteria are deposited in the first section at full strength from the source.
