Growths of micro organisms require nutrients and environment conditions. Agar streak plates are an essential tool in microbiology. The microbiology society, in association with the microbiology in schools advisory committee misac. The loopneedle method of quantitative streaking, preliminarily, appears to be more comparable to automated methods than the looploop method. There are many different types of methods used to streak a plate. Various patterns of streaking but three methods are commonly used in most of the microbiology laboratories for the isolation of microorganism in pure cultures which are as follows parallel streaking method quadrant zigzag streaking method quadrant. This video explains about the different streak plate techniques and the purpose of the technique. 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. The most common method to isolate individual cells and produce a pure culture is to prepare a streak plate. It is consists of undigested food, dead bacteria, and mucosa. In the streak plate method, a small droplet of and to keep track of growth and developmental changes. In order to inoculate a tube or plate with a desired microbial culture, students will use some type of. The streaking process will dilutes out the sample that was placed in the initial region of the agar surface. Feb 23, 2018 streak the loop containing the bacteria at the top end of the agar plate moving in a zigzag horizontal pattern until of the plate is covered.
As these grow, they will run into each other to form a solid lawn of growth. If there is more than one type of colony, each type should be streaked again on. Plate streaking methods blood agar and macconkey agar for urine cultures 1 ul disposable loop inoculate in one continuous streak down the middle of the plate. Aseptic technique, dilution, streaking, and spread.
Microbiology methods basic techniques of biotecnologies streaking technique to obtain pure cultures the skin and many mucosal surfaces of the human body support large numbers of microorganisms that comprise the normal, or indigenous, flora. This type of experiment, called a plaque assay, also provides scientists a standardized. A total of six plates were made per dilution and incu. Put off the shoes before entering to operate the apparatus. Isolate single bacterial colonies by the streakplating method. When streaking plates, the first area inoculated by moving the loop back and forth many times will contain tens of millions of bacteria at a high density in a small area. Discussion streaking is a technique used in microbiology to isolate a pure strain from a single species of microorganism, often bacteria. Figure 23 demonstrates the most common patterns, but they are not the only methods. If you used the same zig zag streaking pattern, the. The first procedure that needed to be done was to streak the unknown out on a trypticase soy agar plate, using the t streak method described in the lab manual this needed to be done in order to test the purity of the unknown.
This method involves the determination of nucleotide sequence in the given dna. Interestingly, these methods have barely changed during. Microbiology is a popular option for practical work in schools. Remove a small amount of bacterial growth either a loopful from a broth culture or a single. Feces stool also contain excretory substances which excreted from bile into the intestine.
Isolate single bacterial colonies by the streak plating method. Prepare two streak plates by following two of the 3 streaking patterns. It is essentially a dilution technique used for isolation of discrete colonies and requires that the number of organisms in the inoculums be reduced. Microbiology module methods of isolation of bacteria microbiology 116 notes streak plates 1. Acceptable if 10 cfu target grow nontarget cfu incubate as per method nonselective agar 10l streak. Methods of culturing microorganisms 3 five basic techniques 4 fig. They allow bacteria and fungi to grow on a semisolid surface to produce discrete colonies. After the plates were incubated and grown, the morphology was observed and recorded and a gram stain was performed. 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. There are alternative methods for preparing a streak plate but the method shown. Aug 10, 2016 in microbiology laboratory, horizontal ty pe of laminar air flow is used to supply the air through f ilter. The semiquantitative inoculation method is the primary method of inoculating primary media.
This uses either the three streak or four streak methods shown above. Still, this present article demonstrates a method that can greatly improve the efficiency of perhaps the most basic of techniques the streaking on agar plates. A microbiological culture can be grown so that the organism can be identified, studied, or tested. In microbiology, streaking is a technique used to isolate a pure strain from a single species of microorganism, often bacteria. Streak plate technique is one of the isolation techniques u. The object of any streaking pattern is the continuous dilution of the inoculum to give many well isolated colonies. Do not stab the butt as it will serve as a color control. Flame the inoculating loop until it is red hot and then allow it to cool. However, the employment of the streaking methods and pattern of streaking varies from lab to lab. Sterilize the inoculating loop in the bunsen burner by putting the loop into the flame until it is red hot. Picking a technique is a matter of individual preference and can also depend on how large the number of microbes the sample contains. A sterile loop is then used to spread the bacteria out in one direction from the initial site of inoculation. Streaking technique obtain pure cultures cultivation of.
The streak plate method is a rapid qualitative isolation method. As a new microbiologist, begin with 4 section streaking to increase the potential of. Streaking microbial cultures on agar plates university of missouri. The streak plate method will require constant use of the streaking loop. Novel restreaking technique methods in microbiology. After this initial step, return and spread the specimen into 34 sections. The technique consists of pouring a suitable sterile medium into sterile petriplate and allowing the medium to solidify.
After streaking this area, there are still many bacteria on the loop. The competency of microbiology professionals is obtained through the theoretical knowledge gained in the class and the practical skills and applications that lead to the better understanding and interpretations the subject matter. Basic practical microbiology why microbiology matters. Study the diagram and read the tips below the diagram before you begin the streak plate. L loops in quadrant streaking pattern, or a central single streaking throughout the plate followed by a zigzag pattern. This uses either the three streak or four streak methods. Starting the streak on the side of the plate farthest from. They are all valid so long as single, wellseparated colonies are produced.
Pdf haematology microbiology procedure magendira mani. A source of bacteria stock culture, previously streaked agar plate or. The streak plate method is a rapid and simple technique for obtaining wellisolated colonies on the surface of the plate, each arising hopefully from a single cell, so that pure cultures from a mixture can be established. Jan 14, 2020 a wrong streaking method can ruin your plate. Innate errors of quantitative streaking methodologies. Novel re streaking technique methods in microbiology isolation of microbial strains is one of the most fundamental procedures in microbiology, whether it is in the environmental or the medical aspect. 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. The parallel streak quadrant method is commonly used in the labs for the isolation of microorganism. Streak plate method principle, methods, significance. Alternatively, if too many bacteria are plated, then overlap of cells may occur and increase the. Streak a sample from mix b onto one plate of nutrient agar na. Antibacterial activity assessment of textile materials. Streak plate technique for isolation of microorganism. 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.
Two types of culture media, bap biomerieux, craponne, france made by sheep blood agar and mck biomerieux, craponne, france made by macconkey agar, were used. It involves four individual streaks the best results are obtained when the loop is sterilized or flamed between streaks when using a stainless steel inoculating loop. This method is used most commonly to isolate pure cultures of bacteria. This method was in use earlier to study phylogenetic relationship amongst bacteria. An aquatic sample is taken and preserved till further investigation in some sort of vessel, a falcon tube for example. Perform plating procedures for enumeration of bacteria without contaminating media and self. The streak plate method can be timeconsuming, especially if you are going to prepare a large sample size.
A small amount of sample is placed on the side of the agar plate either with a swab, or as a drop from an inoculating loop. However, when chemicals are incorporated into media to prevent the growth of certain bacterial mar 11, 2017 for example the bacteria will only grow on the pattern made on the solidified agar during the streak plate method. If there is more than one type of colony, each type should be streaked. Remember that the object of streaking a broad plate surface is to dilute the culture so as to. Rotate the plate 90 degrees and using the same swab, streak the plate again. 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. Uk standards for microbiology investigations issued by the standards unit, public health england scope of document this uk smi describes the basic methods of inoculating primary culture media with clinical specimens including swabs, fluid, urine, faeces, tissue and cannulae. The society for general microbiology sgm is a learned society with over 5,000 members worldwide who work in universities, industry and research institutes. A sterile loop flamed until red hot, then cooled by touching the agar away from the inoculated sample is then used to spread the bacteria out in. This manual, which explains the basic techniques necessary to carry out microbiology experiments safely and effectively, is intended as a guide for teachers and technicians. Thus methods used with this purpose have been used since the emergence of the field.
Minimize the amount of agar and the length of time the agar is exposed to the environment during the streak process. Microbiology module bacterial identification tests microbiology notes procedure christensens urea agar 4, 5 use a heavy inoculum from an 18 to 24hour pure culture to streak the entire slant surface. If you swab a door handle, where bacteria are likely to be present, and then pass the swab. Further studies need to be performed to assess this method. Streak plate technique is used for the isolation into a pure culture of the. Within a few weeks, however, these procedures will be second nature. Zig zag streak the steps of the zig zag streak are. When using a wire loop to transfer bacteria from cultures grown on solid. The streaking is done using a sterile tool, such as a cotton swab or commonly an inoculation.
At first, many of the manipulations and methods of handling materials will seem awkward. Note that na plates are marked with one blackcolored line. Laboratory methods in microbiology is a laboratory manual based on the experience of the authors over several years in devising and organizing practical classes in microbiology to meet the requirements of students following courses in microbiology at the west of scotland agricultural college. Once again, the idea is to obtain isolated colonies after incubation of the plate. There are two most commonly used streak patterns, a three sector t streak and fourquadrant streak methods. How many types of streaking methods are there in microbiology. Obtain one macconkey agar mac, two brain heart infusion bhi and one columbia nalidixic acid agar cna plates. The society aims to encourage a greater public understanding of microbiology and biotechnology by school pupils and the public.
There are two most commonly used streak patterns, a three sector t streak and a four quadrant streak methods. Aseptically obtain a sample using an inoculating loop or sterile cotton swab. The lid of the agar plate has to be opened just sufficiently enough to streak the plate with the inoculation loop. 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. Streak plate method principle, methods, significance, limitations. Pdf veterinary microbiology laboratory manual sultan a. Methods of streak plate there are many different types of methods used to streak a plate. This technique is called a zig zag streak and is one type of isolation streak method. At least 500 different types of me dia are used in culturing and identifying microorganisms. Lets illustrate the method with a practical example. A microbiological culture, or microbial culture, is a method of multiplying microbial organisms by letting them reproduce in predetermined culture medium under controlled laboratory conditions. If there is more than one type of colony, each type should be strea. The streaking patterns shown in the figure below result in continuous dilution of the inoculum to give well separated surface colonies.
The first quadrant is a tight streak, and the most growth is here. Manual versus automated streaking system in clinical. Pick an isolated colony from the agar plate culture and spread it over the first quadrant approximately 14 of the plate using close parallel streaks or insert your loop into the tubeculture bottle and remove some inoculum. Due to ambiguity of the interpretation and the availability of more specific techniques such as rrna homology, this is no longer used in classification. Streak a sample from your morphological unknown culture onto one plate of the medium type specified by your instructor. 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.
Eventually, it will wear out and you need to change it every once in a while. If there is more than one type of colony, each type should be s. Culturing microorganisms on a medium nutrient agar peptone aimto culture the microorganisms in a nutrient agar by various methods principlethe isolation method most commonly used to get distinct culture is the streak plate method. Now consider streaking a sample from a pure tsa broth culture prepared for you. Streaking microbial cultures on agar plates agar streak plates are an essential tool in microbiology. Clearly labeling your plates to identify the microorganism only takes a few. Jan 09, 2020 aatcc test method 147 pdf category, microbiology laboratory. The method most often used in the clinical laboratory is the quadrant method.
Mar 23, 2020 there are many different types of methods used to streak a plate. To inoculate the primary media, inoculate the outer edge of each primary agar, starting with the least selective agar and progressing to the most selective. Sterilize the loop again in the flame and cool it at the edge of the agar away from the bacteria in the plate that you just streaked. Streak plate methods and techniques in microbiology youtube. Choosing a streaking pattern is a matter of individual preference and depends upon the number of microorganisms in the sample. The society aims to encourage a greater public understanding of microbiology and biotechnology by school. With this method, a small amount of sample is placed on the side of the agar plate either with a swab, or as a drop from an inoculating loop if the sample is a liquid. Microbial cultures are foundational and basic diagnostic methods used as a research tool in molecular biology microbial cultures are used to determine the type of organism, its abundance in the sample. With the same loop, streak out the entire plate at 90o to the initial inoculum. These colonies can be used to help identify the organism, purify the strain free of contaminants, and produce a pure genetic clone. Click on each button to learn about the semiquantitative, quantitative, lawn of growth, and isolation methods of inoculating media. Stool examination methods are important for patient diagnosis.
Other selelctive media used for the growth of specific micro organisms is given in the appendix. Hold the plate lid so that it acts as a shield protecting the agar surface from microbes falling from the air. Acceptable if 10 cfu or no growth of nontarget liquid media. We will begin by performing several different types of transfers with different tools.
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