{"id":262047,"date":"2025-07-20T10:48:02","date_gmt":"2025-07-20T10:48:02","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=262047"},"modified":"2025-07-20T10:48:05","modified_gmt":"2025-07-20T10:48:05","slug":"which-of-the-following-would-not-be-found-in-columbia-cna-with-5-sheep-blood-agar-plates","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/07\/20\/which-of-the-following-would-not-be-found-in-columbia-cna-with-5-sheep-blood-agar-plates\/","title":{"rendered":"Which of the following would not be found in Columbia CNA with 5% sheep blood agar plates"},"content":{"rendered":"\n<p>Which of the following would not be found in Columbia CNA with 5% sheep blood agar plates? <\/p>\n\n\n\n<p>A Casein <\/p>\n\n\n\n<p>B Agar <\/p>\n\n\n\n<p>C Sodium chloride <\/p>\n\n\n\n<p>D Phenylethyl alcohol <\/p>\n\n\n\n<p>E Nalidixic acid<\/p>\n\n\n\n<p><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-ast-global-color-6-color\">The correct answer and explanation is:<\/mark><\/strong><\/p>\n\n\n\n<p>The correct answer is <strong>E) Nalidixic acid<\/strong>.<\/p>\n\n\n\n<p>Columbia CNA with 5% sheep blood agar is a selective and differential medium commonly used in microbiological laboratories to grow Gram-positive organisms while inhibiting Gram-negative bacteria. It contains several key components to serve these functions.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>A) Casein<\/strong>: Casein is a protein found in milk and is often included in media to provide essential nitrogen and carbon sources for bacterial growth. It can support the growth of a wide variety of organisms, including those on Columbia CNA.<\/li>\n\n\n\n<li><strong>B) Agar<\/strong>: Agar is a gelling agent that solidifies the medium, allowing bacteria to grow on a stable surface. It is a fundamental component of most solid microbiological media, including Columbia CNA.<\/li>\n\n\n\n<li><strong>C) Sodium chloride<\/strong>: Sodium chloride is included to maintain the osmotic balance of the medium. This helps prevent cells from bursting or shrinking due to osmotic pressure, allowing for normal bacterial growth.<\/li>\n\n\n\n<li><strong>D) Phenylethyl alcohol (PEA)<\/strong>: Phenylethyl alcohol is included in Columbia CNA to selectively inhibit the growth of Gram-negative bacteria. It does this by interfering with the permeability of the outer membrane of Gram-negative organisms. This allows for selective growth of Gram-positive bacteria like staphylococci and streptococci.<\/li>\n\n\n\n<li><strong>E) Nalidixic acid<\/strong>: Nalidixic acid is an antibiotic that targets bacterial DNA replication. While it is used in some selective media, it is not a component of Columbia CNA with 5% sheep blood agar. This medium relies on phenylethyl alcohol for selective inhibition, not nalidixic acid.<\/li>\n<\/ul>\n\n\n\n<p>In summary, nalidixic acid is not a component of Columbia CNA with 5% sheep blood agar because the medium uses phenylethyl alcohol as its selective agent, and nalidixic acid would not typically be included in this type of medium.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Which of the following would not be found in Columbia CNA with 5% sheep blood agar plates? A Casein B Agar C Sodium chloride D Phenylethyl alcohol E Nalidixic acid The correct answer and explanation is: The correct answer is E) Nalidixic acid. Columbia CNA with 5% sheep blood agar is a selective and differential [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[25],"tags":[],"class_list":["post-262047","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/262047","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/comments?post=262047"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/262047\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=262047"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=262047"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=262047"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}