Gram stain is a very important differential staining technique used in the initial characterization and classification of bacteria in microbiology. It was developed by danish microbiologist hans christian gram in 1884 as an effective method to distinguish between bacteria with different types of cell walls, and even today it remains one of the most frequently used staining techniques. In 1884, hans christian gram, a danish doctor, developed a differential staining technique that is still the cornerstone of bacterial identification and taxonomic division. Gram stain and acidfast stain are most popularly known as differential stains. Heat or a lipid solvent is used to carry the first stain, carbolfuchsin, into the cells. Simple staining implies the use of only a single stain, which is usually sufficient to reveal the morphological features of most microbial cells, including relative size, shape, and characteristic arrangements for groups of cells. The gram, ziehl neelsen acid fast, and endospore stains are differential tests used to help. In the first step the smear is stained with basic dye crystal violet primary stain followed by treatment with iodine solution functioning as mordant.
Differential staining is a staining process which uses more than one chemical stain. The gram is a differential stain that enables classification of the bacteria into two large groups, the gram. The most useful staining procedure in medical microbiology. So this method is also called ziehlneelsen staining techniques. Differential and cytological staining techniques theory. Acidfast stain principle, procedure, interpretation and. When it is necessary to demonstrate whether or not a particular organism possesses a capsule, is flagellated, or forms endospores, special staining techniques must be. Staining is a supplementary method that gives divergence to the microscopic image for better vision under the microscope. Uk standards for microbiology investigations issued by the standards unit. Another differential staining technique is acidfast technique which differentiates species of mycobacterium from other bacteria.
This test differentiate the bacteria into gram positive and gram negative bacteria, which helps in the classification and differentiations of microorganisms. Gram staining is still the cornerstone of bacterial identification and taxonomic division. Differential staining of bacteria microbiology laboratory. Microbiology module common staining technique microbiology 20 notes 2 common staining technique 2. Techniques used in studying about growth of bacteria. Gram staining is the common, important, and most used differential staining techniques in microbiology, which was introduced by danish bacteriologist hans christian gram in 1884. Principle of negative staining negative staining requires the use of an acidic stain such as india ink or nigrosin.
Gram staining is the common, important, and most used differential staining techniques in microbiology, which was introduced by danish bacteriologist hans. Gram stain is a very important differential staining techniques used in the initial characterization and classification of bacteria in microbiology. Neelsen in 1883 used ziehls carbolfuchsin and heat then decolorized with an acid alcohol, and counter stained with methylene blue. To use and relate the gram stain to the study of bacterial cell morphology, and as an. It is one of the most important and widely used differential staining techniques in microbiology. Types of staining techniques used in microbiology and. To learn the techniques of gram staining, nigrosin staining and koh test. There are two important differential stains used in microbiology. The gram stain, developed by christian gram in the 1800s, was the first differential staining technique in use and is still an important tool for distinguishing between two main types of bacteria grampositive and gramnegative. This differential staining procedure separates most bacteria into two groups on the basis of cell wall composition. There are a variety of staining methods like simple, differential and special staining that are used in labs to examine the bacteria.
Staining microscopic specimens microbiology lumen learning. Will retain counterstain second color applied during differential staining. Bacterial classification, structure and function introduction the purpose of this lecture is to introduce you to terminology used in microbiology. A differential staining microscopy selectivity delignification. Leishman staining technique principle, preparation. Microbiology acid fast staining technique and its details. Staining techniques in microbiology a presentation by g. Microbiological laboratory techniques clinical gate. A differential stain is a specific type of staining that allows for microbe identification, and distinguishing between cells in a mixed sample. Sterilization is the destruction or removal of all microorganisms, including bacteria and their endospores, viruses, fungi, and prions. Differential staining techniques in microbiology, differential staining techniques are used more often than simple stains as a means of gathering information about bacteria.
This is very different from simple staining techniques that simply add color and contrast to a slide. Scope of document the document covers the methods for the staining procedures commonly used in clinical microbiology laboratories for. This technique was introduced in 1884 by danish physician christian gram. Special stains differential stains basic techniques of. Using multiple stains can better differentiate between different microorganisms or structurescellular components of a single organism differential staining is used to detect abnormalities in the proportion of different white blood cells in the blood. Gram stain the previous lab introduced simple staining techniques that enable microbiologists to observe the morphological characteristics of bacteria. The microscope is a very important tool in microbiology, but there are limitations when it comes to. Choose from 500 different sets of microbiology staining techniques flashcards on quizlet.
With a simple stain, you observe what three things. Negative staining principle, procedure and result interpretation objectives of negative staining to perform a negative staining procedure. It is the differential staining techniques which was first developed by ziehl and later on modified by neelsen. Gram staining helps to identify bacterial pathogens in specimens and cultures by their gram reaction gram positive and gram negative and morphology coccirod. Grampositive bacteria gramnegative bacteria provides useful information for disease treatment.
So, now lets have a discussion on some of the basic techniques involved in microbiology. Uk standards for microbiology investigations issued by the standards unit, public health england. Distinguishes bacteria of two large and medically important groups. The gram stain technique basic protocol is a differential staining technique since it reacts differently with different types of bacteria based on their cell wall. Gram staining is a differential staining technique, which separates. Although simple stains are useful, they do not reveal details about the bacteria other than morphology and arrangement. This staining technique is used to demonstrate the presence of acid fast bacilli. The gram stain is a complex and differential staining procedure that remains a. The wide application of sterilization processes makes it necessary to impose strict control measures to validate the. Gram stain developed in 1884 by hans gram, a danish microbiologist. Special stains some bacteria have characteristic surface structures such as capsules or flagella and internal components e. The gram stain is a differential staining technique that can detect two different types of bacteria based on differences in the cell wall structure. Introduction as bacteria consist of clear protoplasmic matter, differing but slightly in refractive index from the medium in which they are growing, it is difficult with the ordinary microscope, except when special methods of illumination are used, to set them in the unstained condition. Differential staining methods, which typically require more than one stain and several steps, are referred to as such because they permit the differentiation of cell types or cell structures.
Acidfast staining technique is a differential staining technique in bacteriology. Acidfast staining technique helps us to differentiate the organism as acidfast and nonacid fast organisms. Types of different staining techniques of microorganisms. This multistep, sequential staining protocol separates bacteria into four groups based on cell morphology and cell wall structure. To obtain additional information, various specialized differential staining procedures have been developed. Differential stains react differently to different types of bacteria. To understand the benefit obtained from visualizing unstained microorganisms. Objectives to learn the technique of smear preparation. Differential staining, part ii with special techniques, it is possible to visualize endospores, capsules, cell walls, flagella, metachromatic granules and other intracellular constituents of microbial cells. This staining technique was discovered by scientist paul ehrlich in 1883. Simple staining involves adding a basic, cationic dye to the organism. Stains and dyes are frequently used in biological tissues for viewing, often with the aid of different microscopes. The gram stain is a differential method of staining used to assign bacteria to one of two groups grampositive and gramnegative based on the properties of their cell walls. Staining techniques in microbiology linkedin slideshare.
Staining simply means coloring of the micro organisms with. The previous lab introduced simple staining techniques that enable microbiologists to observe the morphological characteristics of bacteria. Learn microbiology staining techniques with free interactive flashcards. This can be accomplished by physical methods such as heat, radiation, and filtration, or by chemical methods. The gram stain is a differential stain commonly used in the microbiology laboratory that differentiates bacteria on the basis of their cell wall structure. Methods of culturing microorganisms 3 five basic techniques 4 fig. Gram staining helps to identify bacterial pathogens in specimens and cultures by their gram reaction grampositive and gramnegative and morphology coccirod. Differential staining is a technique which uses more than one stain to differentiate bacteria.
This technique differentiates species of mycobacterium from other bacteria. The gram stain procedure is a differential staining procedure that involves multiple steps. Gram stain technique is a differential staining technique, which separates bacteria into two groups discussed in earlier chapters, grampositive bacteria and gramnegative bacteria. The steps of the gram stain procedure are listed below and illustrated in table 1. Gram stain in 1884, hans christian gram, a danish doctor, developed a differential staining technique that is.
Some staining techniques, such as the gram and ziel neelsen stains, although of great diagnostic value because of their differential staining properties for specific bacteria, reveal little. While there are a variety of differential staining techniques, the gram stain is the one most commonly used by microbiologist. Gram staining method, the most important procedure in microbiology, was developed by danish physician hans christian gram in 1884. The procedure of leishman staining may vary as per the purpose of staining that means whether the staining is done for the examination of blood cells morphology, toxic granules in leucocytes, type of anemia etc. This unit describes two methods of capsule staining. Differential staining techniques commonly used in clinical settings include gram staining, acidfast staining, endospore staining, flagella staining, and capsule. Lab readings linked on the differential staining of bacterial cells laboratory main page of the virtual microbiology classroom purpose the purpose of this project is to 1 acquaint students with three common bacterial stains and their clinical uses and 2 acquaint students with the parts of the microscope and proper microscopy techniques. Hanging drop technique enables viewing of size shape, arrangement and motility of live microorganisms in fluid media. Can be used to distinguish among different groups of bacteria.
The procedure is named for the person who developed the technique, danish bacteriologist hans christian gram. Cover different classification schemes for grouping bacteria, especially the use of the gram stain 2. To study the staining of bacteria with special stains that help to reveal their morphology thereby enhancing the contrast using a bright field microscope. It is utilized for distinguishing organisms depending on their staining properties.
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