The Ziehl-Neelsen stain , also known as the acid-fast stain , is a bacteriological staining technique used in cytopathology and microbiology to identify acid-fast bacteria under microscopy , particularly members of the Mycobacterium genus. This staining method was initially introduced by Paul Ehrlich (1854–1915) and subsequently modified by the German bacteriologists Franz Ziehl (1859–1926) and Friedrich Neelsen (1854–1898) during the late 19th century.
24-547: The acid-fast staining method, in conjunction with auramine phenol staining , serves as the standard diagnostic tool and is widely accessible for rapidly diagnosing tuberculosis (caused by Mycobacterium tuberculosis ) and other diseases caused by atypical mycobacteria , such as leprosy (caused by Mycobacterium leprae ) and Mycobacterium avium-intracellulare infection (caused by Mycobacterium avium complex ) in samples like sputum , gastric washing fluid, and bronchoalveolar lavage fluid . These acid-fast bacteria possess
48-443: A Gram stain . It can also be used to stain a few other bacteria, such as Nocardia . The reagents used for Ziehl–Neelsen staining are carbol fuchsin , acid alcohol, and methylene blue . Acid-fast bacilli are bright red after staining. Ziehl–Neelsen staining is a type of narrow spectrum fungal stain. Narrow spectrum fungal stains are selective, and they can help differentiate and identify fungi. The results of Ziehl–Neelsen staining
72-433: A diarrhea , sometimes with a persistent cough in immunocompetent hosts. Other apicomplexan pathogens of humans include the malaria parasite Plasmodium and the toxoplasmosis parasite Toxoplasma . Unlike Plasmodium , which transmits via a mosquito disease vector , and Toxoplasma which needs a feline as definitive host , Cryptosporidium does not use a vector, and is capable of completing its lifecycle within
96-434: A high density of cell wall material, such as acid-fast bacteria. The Ziehl-Neelsen stain is a two step staining process . In the first step, the tissue is stained with a basic fuchsin solution, which stains all cells pink. In the second step, the tissue is incubated in an acid alcohol solution, which decolorizes all cells except for acid-fast cells, which retain the color and appeared as red. The mechanisms by which this color
120-670: A host. It can also resist many common disinfectants , including chlorine -based disinfectants. Many treatment plants that take raw water from rivers , lakes , and reservoirs for public drinking water production use conventional filtration technologies. Direct filtration, which is typically used to treat water with low particulate levels, includes coagulation and filtration but not sedimentation. Other common filtration processes including slow sand filters , diatomaceous earth filters , and membranes will remove 99% of Cryptosporidium . Membranes and bag- and cartridge-filter products remove Cryptosporidium specifically. Cryptosporidium
144-487: A much higher negative predictive value. The mechanism of action of the Ziehl-Neelsen stain is not completely understood, but it is thought to involve a chemical reaction between the acidic dyes and the cell walls of the bacteria . The acidity of the dyes causes them to bind more strongly to the cell walls of the bacteria than to other cells or tissues . This results in the selective staining of only those cells that have
168-435: A single host. It results in cyst stages that are excreted in feces or through inhalation of coughed on fomites and are capable of transmission to a new host. A number of species infect mammals. In humans, the main causes of disease are C. parvum and C. hominis (previously C. parvum genotype 1). C. canis , C. felis , C. meleagridis , and C. muris can also cause disease in humans. Cryptosporidiosis
192-471: A stain for mycobacterium tuberculosis, called the alum hematoxylin stain. Franz Ziehl then altered Ehrlich's staining technique by using carbolic acid as the mordant. Friedrich Neelsen kept Ziehl's choice of mordant but changed the primary stain to carbol fuchsin. Ziehl and Neelsen's modifications together have developed the Ziehl–Neelsen stain. Another acid-fast stain was developed by Joseph Kinyoun by using
216-561: A waxy lipid-rich outer layer that contains high concentrations of mycolic acid , rendering them resistant to conventional staining techniques like the Gram stain . After the Ziehl-Neelsen staining procedure using carbol fuchsin , acid-fast bacteria are observable as vivid red or pink rods set against a blue or green background, depending on the specific counterstain used, such as methylene blue or malachite green , respectively. Non-acid-fast bacteria and other cellular structures will be colored by
240-557: Is a second, less likely route of infection. The genome of C. parvum , sequenced in 2004, was found to be unusual amongst eukaryotes in that the mitochondria seem not to contain DNA . A closely related species, C. hominis , also has its genome sequence available. Cryptosporidium has three developmental stages: meronts , gamonts and oocysts . They reproduce within the intestinal epithelial cells . The Cryptosporidium spore phase ( oocyst ) can survive for lengthy periods outside
264-493: Is an apicomplexan genus of alveolates which are parasites that can cause a respiratory and gastrointestinal illness ( cryptosporidiosis ) that primarily involves watery diarrhea (intestinal cryptosporidiosis), sometimes with a persistent cough (respiratory cryptosporidiosis). Treatment of gastrointestinal infection in humans involves fluid rehydration , electrolyte replacement, and management of any pain. For cryptosporidiosis, supportive treatment and symptom management are
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#1732886857789288-442: Is highly resistant to chlorine disinfection; but with high enough concentrations and contact time, Cryptosporidium inactivation will occur with chlorine dioxide and ozone treatment. In general, the required levels of chlorine preclude the use of chlorine disinfection as a reliable method to control Cryptosporidium in drinking water. Ultraviolet light treatment at relatively low doses will inactivate Cryptosporidium . One of
312-518: Is pasteurized to kill any of the bacteria. Mycobacterium tuberculosis that causes tuberculosis (TB) in humans is an airborne bacterium that typically infects the human lungs. Testing for TB includes blood testing, skin tests, and chest X-rays. When looking at the smears for TB, it is stained using an acid-fast stain. These acid-fast organisms like Mycobacterium contain large amounts of lipid substances within their cell walls called mycolic acids. These acids resist staining by ordinary methods such as
336-577: Is produced are not well understood, but it is thought that the interaction of the basic fuchsin with the cell wall components of bacteria creates a new molecule that is responsible for the color. Auramine phenol stain Auramine phenol stain is a stain used in clinical microbiology and histology to identify tuberculosis mycobacteria . There are two types of auramine phenol stains, 1 and 2 to stain mycobacterium species and cryptosporidium respectively. Both are fluorescent stains. The bacteria or
360-506: Is typically an acute, short-term infection, but can recur through reinfection in immunocompetent hosts, or become severe or life-threatening in immunocompromised individuals. In humans, it remains in the lower intestine and may remain for up to five weeks. The parasite is transmitted by environmentally hardy cysts (oocysts) that, once ingested, exist in the small intestine and result in an infection of intestinal epithelial tissue . Transmission by ingestion or inhalation of coughed-on fomites
384-479: Is used to identify the unknown fungi. It is also useful in the identification of some protozoa, namely Cryptosporidium and Isospora . The Ziehl–Neelsen stain can also hinder diagnosis in the case of paragonimiasis because the eggs in sputum sample for ovum and parasite (O&P) can be dissolved by the stain In 1882 Robert Koch discovered the etiology of tuberculosis. Soon after Koch's discovery, Paul Ehrlich developed
408-436: Is variable because many fungal cell walls are not acid fast. An example of a common type of acid-fast fungus that is usually stained with Ziehl–Neelsen staining is called Histoplasma (HP). Histoplasma is found in soil and the feces of birds and bats. Humans can contract histoplasmosis by inhalation of the fungal spores. Histoplasma enters the body and goes to the lungs where the spores turn into yeast. The yeast gets into
432-499: The Ziehl–Neelsen staining technique but removing the heating step from the procedure. This new stain from Kinyoun was named the Kinyoun stain. A typical AFB stain procedure involves dropping the cells in suspension onto a slide, then air drying the liquid and heat fixing the cells. Studies have shown that an AFB stain without a culture has a poor negative predictive value. An AFB culture should be performed along with an AFB stain; this has
456-440: The blood stream and affects lymph nodes and other parts of the body. Usually people do not get sick from inhaling the spores, but if they do they usually have flu like symptoms. Another variation on this staining method is used in mycology to differentially stain acid-fast incrustations in the cuticular hyphae of certain species of fungi in the genus Russula . Some free endospores can be confused with small yeasts, so staining
480-673: The counterstain, allowing for clear differentiation. In anatomic pathology specimens, immunohistochemistry and modifications of Ziehl–Neelsen staining (such as Fite-Faraco staining ) have comparable diagnostic utility in identifying Mycobacterium . Both of them are superior to traditional Ziehl–Neelsen stain. Mycobacterium are slow-growing rod-shaped bacilli that are slightly curved or straight, and are considered to be Gram positive . Some mycobacteria are free-living saprophytes , but many are pathogens that cause disease in animals and humans. Mycobacterium bovis causes tuberculosis in cattle. Since tuberculosis can be spread to humans, milk
504-524: The largest challenges in identifying outbreaks is the ability to verify the results in a laboratory . The oocytes may be seen by microscopic examination of a stool sample, but they may be confused with other objects or artifacts similar in appearance. Most cryptosporidia are 3–6 μm in size, although some reports have described larger cells. Boiling is believed to be the safest option for water contaminated by Cryptosporidium . Dealing with stabilized compost - i.e. composting material that has gone through
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#1732886857789528-428: The parasites appear brilliant greenish yellow against dark background. Mycolic acids of the mycobacteria keep this stain when decolorising with the acid alcohol. The method is more rapid and sensitive than ZN technique. This article related to pathology is a stub . You can help Misplaced Pages by expanding it . Cryptosporidium See § Species Cryptosporidium , sometimes called crypto ,
552-484: The phases where micro-organisms are digesting the organic matter and the temperature inside the composting pile has reached temperature up to 50–70 °C – poses very little risk as these temperatures kill pathogens and even make oocysts unviable. Like many fecal-oral pathogens, the disease can also be transmitted by contaminated food, poor hygiene or turning compost in a local compost site. Testing of water, as well as epidemiological study, are necessary to determine
576-690: The primary treatments for immunocompetent individuals. Anti-diarrheal medication, such as Loperamide , may be effective in slowing the rate of diarrhea. Nitazoxanide is the only drug approved for the treatment of cryptosporidiosis in immunocompetent persons. Supplemental zinc may improve symptoms, particularly in recurrent or persistent infections or in others at risk for zinc deficiency . Cryptosporidium oocysts are 4–6 μm in diameter and exhibit partial acid-fast staining. They must be differentiated from other partially acid-fast organisms including Cyclospora cayetanensis . Cryptosporidium causes cryptosporidiosis , an infection that may present as
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