{"id":1336,"date":"2018-09-04T22:42:58","date_gmt":"2018-09-04T22:42:58","guid":{"rendered":"https:\/\/integrativewellnessandmovement.com\/iwmbasicscience\/?p=1336"},"modified":"2018-09-04T22:50:39","modified_gmt":"2018-09-04T22:50:39","slug":"microbiology-nitratereductiontest","status":"publish","type":"post","link":"https:\/\/integrativewellnessandmovement.com\/iwmbasicscience\/microiology\/microbiology-nitratereductiontest\/","title":{"rendered":"Microbiology: Nitrate Reduction test."},"content":{"rendered":"

Nitrate reduction is an anearobic process and can occur with some aerobes and facultative anaerobes. Anaerobic respiration (an oxidative process) uses nitrates (NO3-) or sulfates (SO4-2) as an oxygen resource, because oxygen is the final electron acceptor.<\/p>\n

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A nitrate broth (standard broth medium with 0.1% potassium nitrate) with 0.1% agar (makes the medium a semisolid promoting an anaerobic environment due to lack of free gas exchange) is inoculated and incubated for 12-48 hours (this test must be done in this time window).<\/p>\n

Five drops of reagent A (sulfanilic acid) is added followed by five drops of reagent B (alpha-naphthylamine). A cherry red color change indicates a positive result (the organism can metabolize nitrates)<\/strong>.<\/p>\n

Other possible situations may be:<\/strong><\/p>\n

A. If there’s no color change after the additions of reagents A and B, the organism was not able to reduce the nitrates.<\/strong> To test this possibility, add a small amount of zinc powder to the test tube (which already has reagents A and B). If nitrates exist, the zinc will reduce the nitrates to nitrites and the medium will turn into a cherry red color (positive test indicates that the organism was not able to metabolize nitrates). IF upon the addition of zinc there was NO color change…then you have situation B (see below).<\/strong><\/p>\n

B. If there’s no apparent color change<\/strong>, the organism may have metabolized and broken down the nitrates (to ammonia or molecular nitrogen) too quickly for testing. This is why it is a good idea to inoculate a few test tubes, and to perform this test at the 12-hour mark and 48-hour mark.<\/p>\n

 <\/p>\n

Clinical significance<\/strong>. A patient with tuberculosis-like symptoms should provide a sputum sample in order to check for Mycobacterium tuberculosis<\/em>. M. tuberculosis<\/em> is the only Mycobacterium<\/em>\u00a0species with the ability to metabolize nitrates.<\/p>\n

 <\/p>\n

Reference<\/p>\n

Cappuccino,\u00a0J.\u00a0G., & Welsh,\u00a0C. (2018).\u00a0Microbiology: A laboratory manual<\/em>.<\/p>\n","protected":false},"excerpt":{"rendered":"

Nitrate reduction is an anearobic process and can occur with some aerobes and facultative anaerobes. Anaerobic respiration (an oxidative process) uses nitrates (NO3-) or sulfates (SO4-2) as an oxygen resource, because oxygen is the final electron acceptor. A nitrate broth (standard broth medium with 0.1% potassium nitrate) with 0.1% agar (makes the medium a semisolid […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[36],"tags":[],"class_list":["post-1336","post","type-post","status-publish","format-standard","hentry","category-microiology"],"_links":{"self":[{"href":"https:\/\/integrativewellnessandmovement.com\/iwmbasicscience\/wp-json\/wp\/v2\/posts\/1336","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/integrativewellnessandmovement.com\/iwmbasicscience\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/integrativewellnessandmovement.com\/iwmbasicscience\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/integrativewellnessandmovement.com\/iwmbasicscience\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/integrativewellnessandmovement.com\/iwmbasicscience\/wp-json\/wp\/v2\/comments?post=1336"}],"version-history":[{"count":2,"href":"https:\/\/integrativewellnessandmovement.com\/iwmbasicscience\/wp-json\/wp\/v2\/posts\/1336\/revisions"}],"predecessor-version":[{"id":1339,"href":"https:\/\/integrativewellnessandmovement.com\/iwmbasicscience\/wp-json\/wp\/v2\/posts\/1336\/revisions\/1339"}],"wp:attachment":[{"href":"https:\/\/integrativewellnessandmovement.com\/iwmbasicscience\/wp-json\/wp\/v2\/media?parent=1336"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/integrativewellnessandmovement.com\/iwmbasicscience\/wp-json\/wp\/v2\/categories?post=1336"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/integrativewellnessandmovement.com\/iwmbasicscience\/wp-json\/wp\/v2\/tags?post=1336"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}