Here we propose the use of gram staining as a fast and costeffective diagnostic tool to differentiate the previously mentioned differential diagnoses, especially in resourcelimited areas. The most widely used staining procedure in microbiology is the gram stain, discovered by the danish scientist and physician hans christian joachim gram in 1884. Gram positive and gram negative, based on the differences of the chemical and physical properties of the cell wall. In most microbiological staining procedures, the bacteria are first fixed to the slide by the heat fixed smear figure 1.
Make a slide of tissue or body fluid that is to be stained. Reagents of gram stain because the gram stain reaction is more widely used and studied than any other stain, it is also the most open to variation in protocol. To use and relate the gram stain to the study of bacterial cell morphology, and as an important step in the identification of a bacterial species. This method is used to distinguish between gram positive and gramnegative bacteria which have. Gram staining technique free download as powerpoint presentation.
Gramstaining was firstly introduced by cristian gram in 1883. The name comes from the danish bacteriologist hans christian gram, who developed the technique gram staining differentiates bacteria by the chemical and physical properties of their cell walls. It was devised by a danish physician, hans christian gram, in 1884. Three introductory chapters cover gramstain procedures, quality control, evaluation, and more. Principle, procedure, interpretation, examples and. Cover different classification schemes for grouping bacteria, especially the use of the gram stain 2. Gram staining is the most sensitive method by which to visualize and recognize nocardiae in clinical specimens.
Mybook is a cheap paperback edition of the original book and will be sold at uniform, low price. We will discuss this and other applications of gram staining in more detail in later chapters. Gram stain or gram staining, also called grams method, is a method of staining used to distinguish and classify bacterial species into two large groups. Abstract named after hans christian gram who developed the method in 1884. Smears that are too thick will be difficult to decolorize and imposable to read. Gram positive bacteria stain blue while gram negative stain red. Pdf gram staining is an empirical method of differentiating bacterial species into two large groups grampositive. 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. Closedopen abscess, lower respiratory, fluid, tissue, or swab supplies. Unless it is a gram stain of a pure culture, there normally should be material staining both colors somewhere on.
Cureus the role of gram staining in staphylococcal. Occurrence of a phosphoric ester in certain bacteria. The viabilitycytotoxicity assay kit for bacteria features dual staining. Gram stain, a widely used microbiological staining technique that greatly aids in the identification and characterization of bacteria. Gram positive bacteria has only the inner plasma membrane and no outer membrane. Add the primary stain crystal violet and incubate 1 minute. An optimized staining technique for the detection of gram positive.
Corynebacterium diptheria seen in gram staining 35. Module common staining technique microbiology 24 notes indeterminate groups as well. Gram stain, grampositive, gramnegative, heat fixation, methanol fixation. Grampositive bacteria thick layer of peptidoglycan90% of cell wall stains purple. Gramnegative pseudomonas aeruginosa bacteria pinkrods. Bacteria are transparent and microscopic clear, like glass. Although simple stains are useful, they do not reveal details about the bacteria other than morphology and arrangement. The gram staining method is named after hans christian gram, the. Gram positive bacteria thick layer of peptidoglycan90% of cell wall stains purple. It is also known as gram staining or gram s method.
Grampositive oval cocci are indicated by preliminary gramstaining, it is recommended that the gram stain be repeated from the plate. This differential staining procedure separates most bacteria into two groups on the basis of cell wall composition. Gram stain definition of gram stain by the free dictionary. The gram stain is a type of differential stain that allows a microbiologist to identify the differences between organisms andor differences within the same organism. Gram staining is a differential staining technique that differentiates bacteria into two groups. The gram stain the gram stain, originally developed in 1884 by christian gram, is probably the most important procedure in all of microbiology. The gram stain is a differential method of staining used to assign bacteria to one of two groups gram positive and gram negative based on the properties of their cell walls. A staining technique used to classify bacteria in which a bacterial specimen is first stained with crystal violet, then treated with an. Introduction gram staining is the most essential and universally used staining technique in bacteriology laboratory. Gramstaining is a specific staining technique invented in 1844 by the. We describe a modification of the gram stain that provides improved contrast of gram positive and gram negative.
The gram stain is the most important staining procedure in microbiology. Gram stain synonyms, gram stain pronunciation, gram stain translation, english dictionary definition of gram stain. Yunusa, et al laboratory perspective of gram staining and its significance in investigations of infectious diseases exposed and increases the porosity of the cell wall. This test differentiate the bacteria into gram positive and gram negative bacteria, which helps in the classification and differentiations of microorganisms. Sputum grams stain and culture can be performed noninvasively and. In this procedure living, potentially pathogenic bacteria are smeared on the glass slide and allowed to air. Google scholar mittwer t, bartholomew jw, kallman bj. The gram stain is a type of differential stain that allows a microbiologist to.
Grampositive bacteria produces a bluepurple color with this staining procedure while gramnegative ones are red in color 5. Gram staining is an empirical method of differentiating bacterial species into. Staining is the process by which color is added to bacteria so they can be viewed under the light microscopes in our classroom. Gramnegative bacteria thin layer of peptidoglycan10% of cell wall and high lipid content stains redpink.
In 1884 a dane, christian gram, while working in berlin, discovered a method of staining microorganisms which has gone under his name ever since that. How to prepare an isolation streak plate powerpoint show or pdf printout printing. A primary stain originally anilinegentian violet was used, but this has been replaced by the more stable crystal violet. Gram stain the previous lab introduced simple staining techniques that enable microbiologists to observe the morphological characteristics of bacteria. If your slide is all one color either pink or blue, then the slide may either have been over or under decolorized. A fundamental laboratory technique that is introduced in general biology and microbiology courses is staining of bacterial cells on glass slides. It is very difficult to observe bacteria without adding color to them. For example, gram staining can help clinicians classify bacterial pathogens in a sample into categories associated with specific properties. Pdf gram staining procedure find, read and cite all the research you need on researchgate. Gram was searching for a method that would allow visualization of cocci in tissue sections of lungs of.
It is recommended that, in order to determine the tendency of an organism with regard to the gram stain, more than one staining procedure be used, and that preparations of the culture be prepared at various stages of growth from 12 hours to several days in age. It includes introduction, history,principle, method of gram staining procedure slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Grampositive bacteria stain deep violet to blue and gramnegative bacteria stain pink to red. The reason for staining bacteria is due to the fact that most bacteria are transparent and cannot be seen through the microscope. Slide preparation purulent material should be selected whenever possible. If gram staining is performed, the usual findings compatible with s. The cvi complex is then washed away from the thin peptidoglycan layer, leaving gramnegative bacteria colorless. Dotson md, jeanine wienerkronish md, in critical care secrets fourth edition, 2007. Prepared microscope slide collection containertube. Heat the slide for few seconds until it becomes hot to the touch so that bacteria are firmly mounted to the slide. A comparison of heat versus methanol fixation for gram. The procedure is named for the person who developed the technique, danish bacteriologist hans christian gram.
Basic classification of medically important bacteria nearly all clinically important bacteria can be detectedvisualized using gram staining method the only exceptions being those organisms. The filter gram stain detected 2 to 100 bacteria, whereas the slide gram stain failed to detect less than 1,000 bacteria. Difference between gram positive and gram negative cell wall is thicker in a gram positive bacteria. Gramnegative bacteria tend to be more resistant to certain antibiotics than grampositive bacteria. Available literature does not mention them, but they are so simple that acetone must have been used in this manner before. Principle, procedure, interpretation, examples and animation.
Gram staining bacteria requires the use of aseptic technique to ensure the sterility of the experiment. Histochemistry of the gramstaining reaction for micro. With the increasing cost of alcohol and the difficulty of obtaining the pure substance, the following uses of acetone for alcohol may prove of interest. To learn the techniques of gram staining, nigrosin staining and koh test. Sterile container or culture transport swab dacron or rayon swab with aluminum or plastic shaft with either stuart or amies liquid medium specimen volume. Flood slide with crystal or gentian violet 60 seconds. Gram negative wall structure gives rise to differences in staining, toxicity, and effects of drugs and disinfectants. The gram stain technique basic protocol is a differential staining technique since it. The best way for students to print out the powerpoint show is to download the pdf version. The gram stain was first used in 1884 by hans christian gram gram,1884. Gram negative bacteria thin layer of peptidoglycan10% of cell wall and high lipid content stains redpink.
Objectives to learn the technique of smear preparation. The gram reaction reflects fundamental differences in the biochemical and structural properties of bacteria. Gram was actually using dyes on human cells, and found that bacteria preferentially bind some dyes. Gram stain report introduction the purpose of this experiment is to determine the shape and gram stain of the bacteria under a microscope. It was a few years later, that the german pathologist carl weigert 1845. History and explanation of the fundamental technique of determinative bacteriology. The gram stain, the most widely used staining procedure in bacteriology. It has to be one of the most repeated procedures done in any lab. Bacterial classification, structure and function introduction the purpose of this lecture is to introduce you to terminology used in microbiology. Overheating of smears when heat fixation is used d. It is used to differentiate between gram positive organisms and gram negative organisms. The microscopicanalysis using gram staining technique showed that majority of the bacterial isolates were grampositive bacteria while only three of.
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