Welcome to microbugz streak plate method of isolation. Pure culture isolating techniques streak pour spread plate method microbial culture techniques hello,my aagam singh sisodiya and in this video you are g. Streaking a mixed broth culture for colony isolation. The pour plate technique can be used to determine the number of microbesml in a specimen. Basic practical microbiology why microbiology matters. Use the sterile cooled loop and draw over the agar surface in the first section, flame and cool. The streak plate procedure is designed to isolate pure cultures of bacteria, or colonies, from mixed populations by simple mechanical.
Streak these cells as a primary streak on the surface of a nutrient agar plate. Jul 21, 2019 bacterial broth, colony counting, isolation of colonies, nutrient agar, pour plate, streak plate. Pdf culture, isolation and identification of bacteria. Agar streak plates are an essential tool in microbiology. Isolation of bacterial colonies using the quadrant method the streak plate procedure is designed to isolate pure cultures of bacteria, or colonies, from mixed populations. Nov 25, 2017 spread plate technique methods of isolating pure culture 3. The streak plate technique is based on progressive dilution of a bacterial sample, and it is performed over the solid media surface of a single petri dish. Streak plate technique streaking is the process of spreading the microbial culture with an inoculating needle on the surface of the media. Streak plate technique is used for the isolation into a pure culture of the organisms mostly bacteria, from a mixed population. All of these methods dilute or thin out a heavy population of bacteria across an agar surface. Isolation of pure cultures from a mixed population. To properly streak a plate for isolation you must spread out the organisms by means of the inoculating loop until single colonies result.
Check out the streak plate culture technique for isolating the microorganism. Know the different methods that are available for isolation. Observation of identical colonies on this second plate will indicate a pure culture. This allows for individual colonies to be isolated from other colonies. Principle the streak plate technique is essentially a method to dilute the number of organisms, decreasing the density. The exact streak plate method that one uses to generate isolated colonies is not too critical.
Nine bacterial species belonging to eight genera have been isolated by growing bacteria in different culture media and following pure culture methods of spread plate and streak plate methods. Isolation can be obtained from any of a variety of specimens. Label the bottom of the plate with the 5 components. During streak plate technique, the loop is heated in between the sector of quadrants.
Return the cap to the tube and set in your tube rack. The differential and selective procedures will be utilized later in this course. Obtaining pure cultures from a mixed population biology. Streak plate method principle, methods, significance. Streaking is a technique for the isolation into a pure culture of the organisms mostly bacteria, from a mixed population. Simpler methods for isolation of a pure culture include. Samples can then be taken from the resulting colonies and a microbiological culture can be grown on a new plate so that the organism can be identified, studied, or tested the modern streak plate method has progressed from the efforts of robert koch and other. The inoculum is streaked over the agar surface in such a way that it thins out the bacteria. Due to a limited population of bacteria in the streaking method, pure culture isolation is quite easier than the pour plate and the spread plate method.
This streak should not occupy more than 14 of the plate, see the diagram below. Streak plate virtual interactive bacteriology laboratory. In order to obtain well isolated discrete colonies, the quadrant streak technique should be used. The inoculum is streaked over the agar surface to isolate colonies on at least a portion of the plate. Obtain one macconkey agar mac, two brain heart infusion bhi and one columbia nalidixic acid agar cna plates.
In microbiology, streaking is a technique used to isolate a pure strain from a single. The following points highlight the six main techniques which are used to develop for the isolation of pure culture from mixed culture. The streak plate method is a rapid qualitative isolation method for obtaining discrete colonies from a mixed population. The spread plate culture method is one of the commonly used culture technique for the isolation of microorganisms, especially the bacteria, in the laboratory. Streak plate isolation method lab 15 1 pure culture a culture of bacteria in which all cells belong to a single. Streaking technique obtain pure cultures cultivation of. For the one plate, streak the mixed culture solely in one direction across the entire plate in one long motion. Isolation by streaking or streak plate technique 4. Obtaining pure cultures cultures composed of cells arising from a single progenitor progenitor is termed a cfu aseptic technique prevents contamination of sterile substances or objects two common isolation techniques streak plates pour plates.
Some individual bacterial cells are separated and wellspaced from each other. The isolation of pure cultures of microorganisms is a technique essential to many types of experiments in microbiology as well as in the identification of potential. Learn vocabulary, terms, and more with flashcards, games, and other study tools. As mentioned in the previous lab, pure cultures are essential for microbiological studies. The streakplate procedure is designed to isolate pure cultures of bacteria, or colonies, from mixed populations by simple mechanical. I am working as assistant professor in a pharmacy college and trainer in vibgyor laboratories. While streaking in successive areas of the plate, the inoculum is diluted to the point where there is only one bacterial cell deposited every few millimeters on the surface of the agar plate. Open the culture tube and collect a sample of specimen using the sterile loop. Prepare two streak plates by following two of the 3 streaking patterns shown in the figure below. In other words, a pure culture of the desired organisms must be obtained. There are several methods by which a pure culture can be obtained, but one of the easiest and most commonly used is the streak plate method. A common method for the isolation of a pure culture from a mixture is by streaking plates.
This general microbiology practical lecture explains the pure culture isolation techniques like streak plate, spread plate and pour plate method. To learn how to perform the aseptic technique to inoculate and grow a pure culture in agar plates. This is useful when you need to separate organisms in a mixed culture or when you need to study the colony morphology of an organism. The techniques commonly used for isolation of discrete colonies initially require that the number of organisms in the inoculums be reduced. Obtaining a pure culture of bacteria is usually accomplished by spreading bacteria on the surface of a solid medium so that a single cell occupies an isolated portion of the agar surface.
The process is called picking colonies when it is done. Streak culture lawn culture stroke culture stab culture pour plate culture liquid culture anaerobic culture methods streak culture used for the isolation of bacteria in pure culture from clinical specimens. The isolation of pure cultures of microorganisms is a technique essential to many types of. Methods of culturing microorganisms different types of media different types of microscopy a single visible colony represents a pure culture or single type of bacterium isolated from a mixed culture. Examine the plates streaked for isolation of a pure culture. Start studying isolation of pure cultures streak plate. Pick off isolated colonies of microorganisms growing on a streak plate and aseptically transfer them to sterile media to obtain pure cultures. The pour plate technique can be used to enumerate bacteria from your sample.
These colonies can be used to help identify the organism, purify the strain free of contaminants, and produce a pure genetic clone. Incubate the plates at 30oc or room temperature until next lab period. Streaking is a method that isolates a pure strain from a species of bacteria. They allow bacteria and fungi to grow on a semisolid surface to produce discrete colonies. Make a second t streak from a different pure culture, labeling the plate as instructed. Place a loopful of broth culture on the surface of a nutrient agar plate, near but not touching the edge. Another important use for pour plates is to create lawns of bacteria which could be used to assay a variety of characteristics such as sensitivity to antibiotics. To study the isolation of pure cultures by using streak plate. Make certain the contents of the broth culture tube are evenly mixed. A properly executed streak plate will yield wellspaced. Before a detailed study of the characteristics of the individual species can be made, each.
Pure culture isolating techniques streak pour spread. After streaking, incubate the culture plates for 2448 hours at a temperature of 3537 degrees celsius within the incubator. The streak plate method of isolation means to spread the microbes on plated agar media so that the individual cells or colony forming units cfus can become isolated and grow into individual, pure colonies. The aim of the procedure is to obtain single isolated pure colonies. The streak plate method is a rapid qualitative isolation method. Introduction the modern streak plate procedure has evolved from attempts by robert koch and other early microbiologists to obtain pure bacterial cultures in order to study them, as detailed in an 1881 paper authored by koch. To begin, the media surface is visually divided into five sections by assigning four fragments of the circumference as the first four sections, and the plates center as the fifth. Ideal results require that only a small amount of inoculum be used and that the surface of the plate be free of droplets of condensed moisture. Serial dilution pour plate quantitative method of pure culture isolation. All techniques are also applied when new algal species are isolated from the wild. Dec 21, 2016 streakplatemethod the most common technique of isolation of bacterial cells on the surface of agar plate is the streaking method it is a simple and a rapid way of isolating cells of bacteria on the agar plate surface through mechanical means as the loop is streaked on the agar surface the bacterial cells are rubbed off until individual separate organisms are deposited on the agar. Use the sterile cooled loop and draw of the agar surface in the second section.
Streak plate method of isolation purpose the streak plate technique is the most widely used method of obtaining isolated colonies from a mix of cultures. In the streaking procedure, a sterile loop or swab is used to obtain an uncontaminated microbial culture. For the other tsa plate, using the above procedure as a guide, perform the streak plate using the fourphase method. Objectives part i be able to streak bacteria for isolation from a mixed culture. In microbiology, streaking is a technique used to isolate a pure strain from a single species of microorganism, often bacteria. As you might guess, the purpose of streaking for isolation is to produce isolated colonies of an organism on an agar plate.
The streak plate method is most commonly used to isolate pure cultures. The sampleinoculum is diluted by streaking it across the surface of an agar plate. Streaking microbial cultures on agar plates agar streak plates are an essential tool in microbiology. Streaking microbial cultures on agar plates university of missouri. Pour plate method the bacterial culture and liquid agar medium are mixed together. What is the difference between streak plate and pour plate. It is essentially a dilution technique that involves spreading a loopful of culture over the surface of an agar plate. In this laboratory exercise, you will be learning the pour plate and streak plate techniques. One loopful of the specimen is transferred onto the surface of a well. The most common method to isolate individual microbes and produce a pure culture is to prepare a streak plate. Practically all specimens of material from natural environments contain a mixed population of microorganisms. Several different methods for getting a pure culture from a mixed culture are available.
Essential methods for maintaining, preparing and using cultures. Isolation of pure algal strain by the agar plating technique. Do not gouge into the medium with the loop and keep the lid over the plate as much as possible. Turn these culture media dishes bottom side up and label the perimeter of the dishes with your initials, date, section number and table number, temperature of incubation, type of medium. The method most often used in the clinical laboratory is the quadrant method. A new loop is recommended for each sector of an isolation streak plate. Most microbiologists repeat streaking from an isolated colony two to three times before they guarantee culture purity.
Isolation of pure cultures streak plate flashcards quizlet. Students may repeat the streak plate procedure above with two other tsa plates. The streak plate technique is the most popular method for isolating specific bacteria from a sample containing a mixture of. This uses either the three streak or four streak methods. Streak the plate, following either the t method or quadrant streak shown below. The dilution or isolation by streaking method was first developed by loeffler and gaffky in kochs laboratory, which involves the dilution of bacteria by systematically streaking them over the exterior of the agar in a petri dish to obtain isolated colonies which will then grow into the number of.
In order to make laboratory studies with pure microbial cultures, microbiologists must start with sterile culture. For your third t streak, you will use the mixed culture of. This protocol describes the use of a mixed broth culture, where the culture contains several different bacterial species or strains. The purpose of spread plating and streak plating is to isolate individual bacterial cells colonyforming units on a nutrient medium. Isolation and preservation of microorganism bacteria. Isolate single bacterial colonies by the streakplating method. A pure culture may be isolated by the use of special media with specific chemical or physical agents that allow the enrichment or selection of one organism over another. Do the initial inoculation then flame the loop, let cool about 15 seconds. Start studying 15 exercise streak plate methods of isolation. Select and transfer a small portion of the monospecific pure colony together with some agar using a sterile platinum loop into a test tube filled with 510 ml of culture medium and shake it regularly during incubation on an illuminated glass rack.
If the plates you prepared are sterile and in good condition, they may be used in this experiment. Sterilize the inoculating needle by flame to make red hot and allow it to cool for 30 seconds. Streak plate method principle, methods, significance, limitations. Ideal results require that only a small amount of inoculum be used and that the surface of the plate be free of droplets of condensed. Techniques of isolation of microorganisms and culture media. Samples can then be taken from the resulting colonies and a microbiological culture can be grown on a new plate so that the organism can be identified, studied, or tested. In streak plate culture method, a sterilized loop or transfer needle is dipped into the mixed culture of the specimen. Using the streak plate method of isolation, obtain isolated colonies from a mixture of microorganisms.
What is streak plate streak plate is the technique in microbiology to isolate pure strain from a single species of microorganisms. One of the most important techniques you will learn this semester is how to streak for isolation. Flame the loop, allow it to cool and streak across the primary streak once or twice and then. A sample is taken from a colony and a microbiological culture is grown on the new plate in order for the organism to be identified properly. The streak plate method is a way to physically separate the microbial population and is done by spreading the inoculate back and forth with an inoculating loop over the solid agar plate.
This method is used for obtaining pure culture from the mixed culture. Moreover, the resulting colonies can be further studied through isolation. The streak plate culture technique for the isolation of microorganism is the most practical method of obtaining discrete and welldeveloped colonies of the microbe in pure cultures. The most common way of separating bacterial cells on the agar surface to obtain isolated colonies. Streak plate the original culture is directly diluted across an agar surface using and inoculating loop.
1395 1342 876 1555 421 77 387 91 714 1023 308 541 168 728 495 1577 426 1315 1405 15 1318 1360 912 235 1555 827 1206 667 346 712 596 79 833 921 1128 1587 1268