securely fixed in place; "the post was still firm after being hit by the car" (同)firm, immobile
firmly or closely; "held fast to the rope"; "her foot was stuck fast"; "held tight" (同)tight
(of a photographic lens or emulsion) causing a shortening of exposure time; "a fast lens"
(of surfaces) conducive to rapid speeds; "a fast road"; "grass courts are faster than clay"
(used of timepieces) indicating a time ahead of or later than the correct time; "my watch is fast"
abstain from certain foods, as for religious or medical reasons; "Catholics sometimes fast during Lent"
abstain from eating; "Before the medical exam, you must fast"
acting or moving or capable of acting or moving quickly; "fast film"; "on the fast track in school"; "set a fast pace"; "a fast car"
at a rapid tempo; "the band played a fast fox trot"
quickly or rapidly (often used as a combining form); "how fast can he get here?"; "ran as fast as he could"; "needs medical help fast"; "fast-running rivers"; "fast-breaking news"; "fast-opening (or fast-closing) shutters"
street name for lysergic acid diethylamide (同)back breaker, battery-acid, dose, dot, Elvis, loony toons, Lucy in the sky with diamonds, pane, superman, window pane, Zen
any of various water-soluble compounds having a sour taste and capable of turning litmus red and reacting with a base to form a salt
having the characteristics of an acid; "an acid reaction"
the syllable naming the fourth (subdominant) note of the diatonic scale in solmization
Mycobacterium tuberculosis (stained red) in tissue (blue).
Acid-fastness is a physical property of certain bacterial and eukaryotic cells, as well as some sub-cellular structures, specifically their resistance to decolorization by acids during laboratory staining procedures.[1][2] Once stained as part of a sample, these organisms can resist the acid and/or ethanol-based decolorization procedures common in many staining protocols, hence the name acid-fast.[2]
The mechanisms of acid-fastness vary by species, although the most well-known example is in the genus Mycobacterium, which includes the species responsible for tuberculosis and leprosy. The acid-fastness of Mycobacteria is due to the high mycolic acid content of their cell walls, which is responsible for the staining pattern of poor absorption followed by high retention. Some bacteria may also be partially acid-fast, such as Nocardia.
Acid-fast organisms are difficult to characterize using standard microbiological techniques, though they can be stained using concentrated dyes, particularly when the staining process is combined with heat. Some, such as Mycobacteria, can be stained with the Gram stain, but they do not take the crystal violet well and thus appear light purple, which can still potentially result in an incorrect gram positive identification.[3]
The most common staining technique used to identify acid-fast bacteria is the Ziehl-Neelsen stain, in which the acid-fast species are stained bright red and stand out clearly against a blue background. Another method is the Kinyoun method, in which the bacteria are stained bright red and stand out clearly against a green background. Acid-fast Mycobacteria can also be visualized by fluorescence microscopy using specific fluorescent dyes (auramine-rhodamine stain, for example).[4] The eggs of the parasitic lung fluke Paragonimus westermani are actually destroyed by the stain, which can hinder diagnosis in patients who present with TB-like symptoms[citation needed].
Contents
1Some acid-fast staining techniques
2Notable acid-fast structures
3References
3.1Online protocol examples
Some acid-fast staining techniques
Ziehl–Neelsen stain (Classic and modified bleach types)[5]
Kinyoun stain
For color blind people (or in backgrounds where detecting red bacteria is difficult) Victoria Blue can be substituted for carbol fuchsin and Picric acid can be used as the counter stain instead of methylene blue, and rest of Kinyoun technique can be used.[6]
Various bacterial spore staining techniques using Kenyon e.g.
Moeller's method
Dorner's method[7] (acid alcohol decolorizer) without the Schaeffer–Fulton[8] modification (decolorize by water)[9]
Detergent method, using Tergitol 7, nonionic polyglycol ether surfactants type NP-7 [10]
Fite stain[11]
Fite-Faraco Staining[12][13]
Wade Fite staining[14]
Ellis and Zabrowarny stain[15][16] (no Phenol/carbolic acid)
Auramine-rhodamine stain
Auramine phenol stain
Notable acid-fast structures
Very few structures are acid-fast; this makes staining for acid-fastness particularly useful in diagnosis. The following are notable examples of structures which are acid-fast or modified acid-fast:
All Mycobacteria - M. tuberculosis, M. leprae, M. smegmatis and atypical Mycobacterium
Actinomycetes (especially some aerobic ones) with Mycolic acid in their cell wall (note Streptomyces do NOT have); not to be confused with Actinomyces, which is a non-acid-fast genera of Actinomycetes
Nocardia
Rhodococcus
Gordonia (Actinomycete)
Tsukamurella
Dietzia
Head of sperm
Bacterial spores, see Endospore
Legionella micdadei
Certain cellular inclusions e.g.
Cytoplasmic inclusion bodies seen in
Neurons in layer 5 of cerebral cortex neuronal ceroid lipofuscinosis (Batten disease).
Nuclear inclusion bodies seen in
Lead poisoning
Bismuth poisoning.
Oocysts of some coccidian parasites in faecal matter, such as:
Cryptosporidium parvum,[17]
Isospora belli[18]
Cyclospora cayetanensis.[19]
A few other parasites:
Sarcocystis
Taenia saginata eggs stain well but Taenia solium eggs don't (Can be used to distinguish)
Hydatid cysts, especially their "hooklets" stain irregularly with ZN stain but emanate bright red fluorescence under green light, and can aid detection in moderately heavy backgrounds or with scarce hooklets.[20]
Fungal yeast forms are inconsistently stained with Acid-fast stain which is considered a narrow spectrum stain for fungi.[21] In a study on acid-fastness of fungi,[22] 60% of blastomyces and 47% of histoplasma showed positive cytoplasmic staining of the yeast-like cells, and Cryptococcus or candida did not stain, and very rare staining was seen in Coccidioides endospores.
References
^Madison B (2001). "Application of stains in clinical microbiology". Biotech Histochem. 76 (3): 119–25. doi:10.1080/714028138. PMID 11475314.
^ abRyan KJ; Ray CG (editors) (2004). Sherris Medical Microbiology (4th ed.). McGraw Hill. ISBN 0-8385-8529-9.CS1 maint: Extra text: authors list (link)
^Reynolds, Jackie; Moyes, Rita B.; Breakwell, Donald P. (November 2009). "Differential staining of bacteria: acid fast stain". Current Protocols in Microbiology. Appendix 3: Appendix 3H. doi:10.1002/9780471729259.mca03hs15. ISSN 1934-8533. PMID 19885935.
^Abe C (2003). "[Standardization of laboratory tests for tuberculosis and their proficiency testing]". Kekkaku. 78 (8): 541–51. PMID 14509226.
^"Acid fast / Auramine-rhodamine". www.pathologyoutlines.com.
^Theory and Practice of Histological Techniques, John D Bancroft, 6th ed, p314
^Dorner, W. 1926. Un procédé simple pour la colouration des spores. Le Lait 6:8-12.
^Schaeffer AB, Fulton M (1933). "A simplified method of staining endospores". Science. 77: 194.
^Endospore Stain Protocol from American Society for Microbiology website Archived 2012-06-01 at the Wayback Machine.
^"Fite-Faraco Staining Protocol for Leprosy Bacilli". www.ihcworld.com.
^"Stainsfile - Fite Faraco". stainsfile.info.
^"Stainsfile - Wade Fite". stainsfile.info.
^Ellis, R. C.; Zabrowarny, L. A. (1993). "Safer staining method for acid fast bacilli". Journal of Clinical Pathology. 46 (6): 559–560. doi:10.1136/jcp.46.6.559. PMC 501296. PMID 7687254.
^[1][dead link]
^Garcia LS, Bruckner DA, Brewer TC, Shimizu RY (July 1983). "Techniques for the recovery and identification of Cryptosporidium oocysts from stool specimens". J. Clin. Microbiol. 18 (1): 185–90. PMC 270765. PMID 6193138.
^Ng E, Markell EK, Fleming RL, Fried M (September 1984). "Demonstration of Isospora belli by acid-fast stain in a patient with acquired immune deficiency syndrome". J. Clin. Microbiol. 20 (3): 384–6. PMC 271334. PMID 6208216.
^Ortega YR, Sterling CR, Gilman RH, Cama VA, Díaz F (May 1993). "Cyclospora species--a new protozoan pathogen of humans". N. Engl. J. Med. 328 (18): 1308–12. doi:10.1056/NEJM199305063281804. PMID 8469253.
^Clavel A, Varea M, Doiz O, López L, Quílez J, Castillo FJ, Rubio C, Gómez-Lus R. "Visualization of hydatid elements: comparison of several techniques". J Clin Microbiol. 37: 1561–3. PMC 84828. PMID 10203521.
^"Dako Products - Agilent" (PDF). www.dako.com. Retrieved 3 December 2018.
^Wages ds, Wear dJ. acid-fastness of fungi in blastomycosis and histoplasmosis. Arch Pathol Lab Med 1982; 106:440-41.
Online protocol examples
Ziehl-Neelsen protocol (PDF format).
Alternate Ellis & Zabrowarny method for staining AFB.
5. HIV感染患者における結核の疫学、臨床症状、および診断 epidemiology clinical manifestations and diagnosis of tuberculosis in hiv infected patients
English Journal
Comparison of a quantitative real-time polymerase chain reaction (qPCR) with conventional PCR, bacterial culture and ELISA for detection of Mycobacterium avium subsp. paratuberculosis infection in sheep showing pathology of Johne's disease.
Sonawane GG, Tripathi BN.SourceIndian Veterinary Research Institute, Regional Station Palampur, Kangra, (HP-176062) India.
SpringerPlus.Springerplus.2013 Dec;2(1):45. Epub 2013 Feb 11.
A quantitative real-time PCR (qPCR) assay employing IS900 gene specific primers of Mycobacterium avium subsp. parartuberculosis (MAP) was compared with conventional PCR, bacterial culture and enzyme-linked immunosorbent assay in 38 sheep showing granulomatous enteritis and lymphadenitis with and wit
Evaluation of the Cobas TaqMan MTB real-time PCR assay for direct detection of Mycobacterium tuberculosis in respiratory specimens.
Lee MR, Chung KP, Wang HC, Lin CB, Yu CJ, Lee JJ, Hsueh PR.Source1 National Taiwan University Hospital;
Journal of medical microbiology.J Med Microbiol.2013 May 8. [Epub ahead of print]
Cobas TaqMan MTB assay is a real-time polymerase chain reaction (qPCR) kit in rapid detection of Mycobacterium tuberculosis (MTB) from clinical specimens. There are, however, limited studies validating its performance. We performed a prospective study in two hospitals in Taiwan including 586 respira
Prevalence of tuberculosis in pigs slaughtered at two abattoirs in Ethiopia and molecular characterization of Mycobacterium tuberculosis isolated from tuberculous-like lesions in pigs.
Arega SM, Conraths FJ, Ameni G.AbstractBACKGROUND: Tuberculosis (TB) is an infectious, granulomatous disease caused by acid-fast bacilli of the genus Mycobacterium. The disease affects practically all species of vertebrates. Although mammalian tuberculosis has been nearly controlled in many developed countries, it is still a serious problem in humans and domestic animals including pigs in developing countries. In Ethiopia, the prevalence of TB in pigs is not known. Therefore, this study was designed to estimate the prevalence of TB in pigs in central Ethiopia and to characterize the causative agents using molecular techniques.
BMC veterinary research.BMC Vet Res.2013 May 6;9(1):97. [Epub ahead of print]
BACKGROUND: Tuberculosis (TB) is an infectious, granulomatous disease caused by acid-fast bacilli of the genus Mycobacterium. The disease affects practically all species of vertebrates. Although mammalian tuberculosis has been nearly controlled in many developed countries, it is still a serious prob
