Differential Staining is a staining process which uses more than one chemical stain. [1] Using multiple stains can better differentiate between different microorganisms or structures/cellular components of a single organism.
Differential staining is used to detect abnormalities in the proportion of different white blood cells in the blood. The process or results are called a WBC differential. This test is useful because many diseases alter the proportion of certain white blood cells. By analyzing these differences in combination with a clinical exam and other lab tests, medical professionals can diagnose disease.
One commonly recognizable use of differential staining is the Gram stain. Gram staining uses two dyes: Crystal violet and Fuchsin or Safranin (the counterstain) to differentiate between Gram-positive bacteria (large Peptidoglycan layer on outer surface of cell) and Gram-negative bacteria.
Acid-fast Stains are also differential stains.
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Gram stain or Gram staining, also called Gram's method, is a method of staining used to classify bacterial species into two large groups: Gram-positive bacteria and Gram-negative bacteria. The name comes from the Danish bacteriologist Hans Christian Gram, who developed the technique.
In bacteriology, gram-positive bacteria are bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their type of cell wall.
Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wall sandwiched between an inner cytoplasmic cell membrane and a bacterial outer membrane.
An endospore is a dormant, tough, and non-reproductive structure produced by some bacteria in the phylum Firmicutes. The name "endospore" is suggestive of a spore or seed-like form, but it is not a true spore. It is a stripped-down, dormant form to which the bacterium can reduce itself. Endospore formation is usually triggered by a lack of nutrients, and usually occurs in gram-positive bacteria. In endospore formation, the bacterium divides within its cell wall, and one side then engulfs the other. Endospores enable bacteria to lie dormant for extended periods, even centuries. There are many reports of spores remaining viable over 10,000 years, and revival of spores millions of years old has been claimed. There is one report of viable spores of Bacillus marismortui in salt crystals approximately 250 million years old. When the environment becomes more favorable, the endospore can reactivate itself from the vegetative state. Most types of bacteria cannot change to the endospore form. Examples of bacterial species that can form endospores include Bacillus cereus, Bacillus anthracis, Bacillus thuringiensis, Clostridium botulinum, and Clostridium tetani.
A complete blood count (CBC), also known as a full blood count (FBC), is a set of medical laboratory tests that provide information about the cells in a person's blood. The CBC indicates the counts of white blood cells, red blood cells and platelets, the concentration of hemoglobin, and the hematocrit. The red blood cell indices, which indicate the average size and hemoglobin content of red blood cells, are also reported, and a white blood cell differential, which counts the different types of white blood cells, may be included.
An agar plate is a Petri dish that contains a growth medium solidified with agar, used to culture microorganisms. Sometimes selective compounds are added to influence growth, such as antibiotics.
Staining is a technique used to enhance contrast in samples, generally at the microscopic level. Stains and dyes are frequently used in histology and in the medical fields of histopathology, hematology, and cytopathology that focus on the study and diagnoses of disease at a microscopic level. Stains may be used to define biological tissues, cell populations, or organelles within individual cells.
A blood film—or peripheral blood smear—is a thin layer of blood smeared on a glass microscope slide and then stained in such a way as to allow the various blood cells to be examined microscopically. Blood films are examined in the investigation of hematological (blood) disorders and are routinely employed to look for blood parasites, such as those of malaria and filariasis.
Acute septic arthritis, infectious arthritis, suppurative arthritis, osteomyelitis, or joint infection is the invasion of a joint by an infectious agent resulting in joint inflammation. Generally speaking, symptoms typically include redness, heat and pain in a single joint associated with a decreased ability to move the joint. Onset is usually rapid. Other symptoms may include fever, weakness and headache. Occasionally, more than one joint may be involved especially in neonates and younger children. In neonates, infants i.e. during the first year of life and toddlers, the signs and symptoms of septic arthritis can be deceptive and mimic other infectious and non-infectious disorders.
Wright's stain is a hematologic stain that facilitates the differentiation of blood cell types. It is classically a mixture of eosin (red) and methylene blue dyes. It is used primarily to stain peripheral blood smears, urine samples, and bone marrow aspirates, which are examined under a light microscope. In cytogenetics, it is used to stain chromosomes to facilitate diagnosis of syndromes and diseases.
Ziehl–Neelsen staining is a type of acid-fast stain, first introduced by Paul Ehrlich. Ziehl–Neelsen staining is a bacteriological stain used to identify acid-fast organisms, mainly Mycobacteria. It is named for two German doctors who modified the stain: the bacteriologist Franz Ziehl (1859–1926) and the pathologist Friedrich Neelsen (1854–1898).
A growth medium or culture medium is a solid, liquid, or semi-solid designed to support the growth of a population of microorganisms or cells via the process of cell proliferation or small plants like the moss Physcomitrella patens. Different types of media are used for growing different types of cells.
Acridine orange is an organic compound that serves as a nucleic acid-selective fluorescent dye with cationic properties useful for cell cycle determination. Acridine orange is cell-permeable, which allows the dye to interact with DNA by intercalation, or RNA via electrostatic attractions. When bound to DNA, acridine orange is very similar spectrally to an organic compound known as fluorescein. Acridine orange and fluorescein have a maximum excitation at 502nm and 525 nm (green). When acridine orange associates with RNA, the fluorescent dye experiences a maximum excitation shift from 525 nm (green) to 460 nm (blue). The shift in maximum excitation also produces a maximum emission of 650 nm (red). Acridine orange is able to withstand low pH environments, allowing the fluorescent dye to penetrate acidic organelles such as lysosomes and phagolysosomes that are membrane-bound organelles essential for acid hydrolysis or for producing products of phagocytosis of apoptotic cells. Acridine orange is used in epifluorescence microscopy and flow cytometry. The ability to penetrate the cell membranes of acidic organelles and cationic properties of acridine orange allows the dye to differentiate between various types of cells. The shift in maximum excitation and emission wavelengths provides a foundation to predict the wavelength at which the cells will stain.
Anaplasma phagocytophilum is a Gram-negative bacterium that is unusual in its tropism to neutrophils. It causes anaplasmosis in sheep and cattle, also known as tick-borne fever and pasture fever, and also causes the zoonotic disease human granulocytic anaplasmosis.
Bacteria are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep biosphere of Earth's crust. Bacteria are vital in many stages of the nutrient cycle by recycling nutrients such as the fixation of nitrogen from the atmosphere. The nutrient cycle includes the decomposition of dead bodies; bacteria are responsible for the putrefaction stage in this process. In the biological communities surrounding hydrothermal vents and cold seeps, extremophile bacteria provide the nutrients needed to sustain life by converting dissolved compounds, such as hydrogen sulphide and methane, to energy. Bacteria also live in symbiotic and parasitic relationships with plants and animals. Most bacteria have not been characterised and there are many species that cannot be grown in the laboratory. The study of bacteria is known as bacteriology, a branch of microbiology.
Medical microbiology, the large subset of microbiology that is applied to medicine, is a branch of medical science concerned with the prevention, diagnosis and treatment of infectious diseases. In addition, this field of science studies various clinical applications of microbes for the improvement of health. There are four kinds of microorganisms that cause infectious disease: bacteria, fungi, parasites and viruses, and one type of infectious protein called prion.
Mycobacterium fortuitum is a nontuberculous species of the phylum Actinobacteria, belonging to the genus Mycobacterium.
White blood cells (WBCs), also called leukocytes or leucocytes, are the cells of the immune system that are involved in protecting the body against both infectious disease and foreign invaders. All white blood cells are produced and derived from multipotent cells in the bone marrow known as hematopoietic stem cells. Leukocytes are found throughout the body, including the blood and lymphatic system.
Endospore staining is a technique used in bacteriology to identify the presence of endospores in a bacterial sample. Within bacteria, endospores are protective structures used to survive extreme conditions, including high temperatures making them highly resistant to chemicals. Endospores contain little or no ATP which indicates how dormant they can be. Endospores contain a tough outer coating made up of keratin which protects them from nucleic DNA as well as other adaptations. Endospores are able to regerminate into vegetative cells, which provides a protective nature that makes them difficult to stain using normal techniques such as simple staining and gram staining. Special techniques for endospore staining include the Schaeffer–Fulton stain and the Moeller stain.
A white blood cell differential is a medical laboratory test that provides information about the types and amounts of white blood cells in a person's blood. The test, which is usually ordered as part of a complete blood count (CBC), measures the amounts of the five normal white blood cell types – neutrophils, lymphocytes, monocytes, eosinophils and basophils – as well as abnormal cell types if they are present. These results are reported as percentages and absolute values, and compared against reference ranges to determine whether the values are normal, low, or high. Changes in the amounts of white blood cells can aid in the diagnosis of many health conditions, including viral, bacterial, and parasitic infections and blood disorders such as leukemia.