{"id":285,"date":"2023-09-16T22:20:05","date_gmt":"2023-09-16T21:20:05","guid":{"rendered":"https:\/\/microregistrar.com\/?p=285"},"modified":"2023-09-16T22:20:05","modified_gmt":"2023-09-16T21:20:05","slug":"smi-notes-investigation-of-infectious-causes-of-dyspepsia-smi-b-55","status":"publish","type":"post","link":"https:\/\/microregistrar.com\/?p=285","title":{"rendered":"SMI notes: Investigation of infectious causes of dyspepsia (SMI B 55)"},"content":{"rendered":"\n<p><strong><em>There are&nbsp; 2 SMIs related to H pylori-&nbsp;Identification of Helicobacter spp. (SMI ID26) &amp;&nbsp;Investigation of infectious causes of dyspepsia (SMI B55).<\/em><\/strong><\/p>\n\n\n\n<h2 class=\"wp-block-heading has-pale-cyan-blue-background-color has-background\">Available tests for the diagnosis of H. pylori infection<\/h2>\n\n\n\n<h6 class=\"wp-block-heading\"><strong>There are 4 major types of tests that we can use to test for H pylori.<\/strong><\/h6>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>1. Urea breath test (UBT)<\/strong><\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li>This is the most accurate test.<\/li>\n\n\n\n<li>It is recommended for both initial tests for someone who never had a test for H pylori before and repeat tests after a course of treatment if indicated.<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>2. Stool antigen test (SAT)<\/strong><\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Two methods are available \u2013&nbsp;<strong>Lab-based ELISA&nbsp;<\/strong>and&nbsp;<strong>near-patient (immunochromatography) test.<\/strong><\/li>\n\n\n\n<li>Lab-based ELISA using monoclonal antibodies have high accuracy for both primary diagnosis and post-treatment diagnosis.<\/li>\n\n\n\n<li>Near-patient tests are less reliable.<\/li>\n\n\n\n<li>Use a fresh faecal sample.<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>3. Serology \u2013 antibody test (HiG)<\/strong><\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Only IgG is tested by ELISA as H pylori are considered to be a chronic infection.<\/li>\n\n\n\n<li>not recommended for most patients, and positives should be confirmed by a second test such as UBT, SAT or biopsy.<\/li>\n\n\n\n<li>has a very good negative predictive value at current (it is reliable when it is negative, less so when it is positive); low prevalence in the developed countries.<\/li>\n\n\n\n<li>most useful in patients with acute gastrointestinal bleeding (and atrophy or gastric malignancy), to confirm negative UBT or SAT. Blood and PPI use interacts with UBT\/SAT.<\/li>\n\n\n\n<li>Blood serology is less predictive and results are variable for current infection. It should not be used in the elderly, children or post-treatment.<\/li>\n\n\n\n<li>Near-patient serology tests are not recommended.<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>4. Microscopy and culture of gastric biopsy<\/strong><\/h4>\n\n\n\n<ul class=\"wp-block-list\" id=\"block-732a90fe-04c9-4aad-9cb4-39ca8b54ec37\">\n<li>Gastric biopsy should be considered<br>1. after 1st failure and if an endoscopy is being done.<br>2. on all cases if there is a 2nd treatment failure.<br>3. In areas where clarithromycin resistance is &gt;20% (The Maastricht IV consensus report).<\/li>\n\n\n\n<li>A biopsy is taken from the site of inflammation \u2013 most commonly gastric antrum, then the main body, and in cases of duodenal ulcer \u2013 duodenal biopsy.<\/li>\n\n\n\n<li>90% sensitivity was reported if the two biopsies are examined.<\/li>\n\n\n\n<li>Ideally, samples should be taken before the antibiotic, but due to the NICE&nbsp;<a href=\"https:\/\/microregistrar.co.uk\/mod\/page\/view.php?id=16\">test and treat<\/a>&nbsp;strategy \u2013 most samples would be from cases of treatment failure.<\/li>\n\n\n\n<li>A period of at least two weeks should have elapsed since the last dose of antimicrobial therapy before the collection of the specimen.<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h4 class=\"wp-block-heading\"><strong><em>Other tests<\/em><\/strong><\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li>PCR for identification and clarithromycin resistance,<\/li>\n\n\n\n<li>histology<\/li>\n\n\n\n<li>MALDI- ToF<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading has-pale-cyan-blue-background-color has-background\"><strong>Laboratory processing of H pylori<\/strong><\/h2>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>Laboratory safety<\/strong><\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Containment level 2.<\/li>\n\n\n\n<li>Laboratory procedures that give rise to infectious aerosols must be conducted in a microbiological safety cabinet.<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>Transporting media<\/strong><\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Dent\u2019s transport medium<\/strong>.&nbsp;<\/li>\n\n\n\n<li>Alternatively isotonic saline.<\/li>\n\n\n\n<li>Process within 6 hours, if not store at 4 degrees C covered with 1mL brain-heart infusion broth for 48 hrs.&nbsp;<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>Stain<\/strong><\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Organisms may be stained using Giemsa or Gram stain. Use carbol fuchsin or Sandiford\u2019s counter stain<\/li>\n\n\n\n<li>Stain smears from blood cultures with acridine orange rather than Gram stain.<\/li>\n\n\n\n<li>Gram-negative, long, thin, straight or slightly curved to spiral-shaped rods. It could be spiral\/helical and even coccoid (in older cultures).<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>Plate selection<\/strong><\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>H pylori selective media <\/strong>or Dent selective media:&nbsp; blood agar with dent supplement (vancomycin, trimethoprim, cefsoludin and amphotericin B). Incubation is&nbsp;microaerophilic, with&nbsp;3-5% H2&nbsp;@35 degrees C for 10 days.<\/li>\n\n\n\n<li>Chocolate\/blood agar<\/li>\n\n\n\n<li>If the urease test has not been performed (i.e. UBT),<strong>&nbsp;use Christenson\u2019s Urea broth<\/strong>.<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>Colony<\/strong><\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Small (1mm), grey, translucent and maybe slightly haemolytic after 3-5 days. Longer incubation may show swarming colonies.<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>Identification<\/strong><\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Catalase, and oxidase positive; Urease reaction is variable for different species, but H pylori is strongly positive.<\/li>\n\n\n\n<li>PCR &amp; MALI ToF (depend on the database).<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>Sensitivity test<\/strong><\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Use MIC. Report \u2013 Amoxicillin, clarithromycin, metronidazole, levofloxacin, tetracycline.&nbsp;<\/li>\n\n\n\n<li>Rifampicin is the 2nd line.&nbsp;<\/li>\n\n\n\n<li>EUCAST breakpoints available.<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>Other tests that can be done on biopsy<\/strong><\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Histology and urease test.<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>H pylori resistance rate in the UK<\/strong><\/h3>\n\n\n\n<figure class=\"wp-block-table\"><table><thead><tr><th>ANTIBIOTIC<\/th><th>RESISTANCE RATE<\/th><\/tr><\/thead><tbody><tr><td>Metronidazole<\/td><td>22-88%<\/td><\/tr><tr><td>Clarithromycin<\/td><td>3-68%<\/td><\/tr><tr><td>Levofloxacin<\/td><td>17%<\/td><\/tr><tr><td>Amoxicillin, rifampicin, tetracycline<\/td><td>3%<\/td><\/tr><tr><td>Rifabutin<\/td><td>&lt;1%<\/td><\/tr><\/tbody><\/table><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>There are&nbsp; 2 SMIs related to H pylori-&nbsp;Identification of Helicobacter spp. (SMI ID26) &amp;&nbsp;Investigation of infectious causes of dyspepsia (SMI [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","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":"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":"","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-4)","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-4)","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-4)","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":""}},"ngg_post_thumbnail":0,"footnotes":""},"categories":[60],"tags":[61],"class_list":["post-285","post","type-post","status-publish","format-standard","hentry","category-laboratory","tag-h-pylori"],"_links":{"self":[{"href":"https:\/\/microregistrar.com\/index.php?rest_route=\/wp\/v2\/posts\/285","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/microregistrar.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/microregistrar.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/microregistrar.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/microregistrar.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=285"}],"version-history":[{"count":2,"href":"https:\/\/microregistrar.com\/index.php?rest_route=\/wp\/v2\/posts\/285\/revisions"}],"predecessor-version":[{"id":651,"href":"https:\/\/microregistrar.com\/index.php?rest_route=\/wp\/v2\/posts\/285\/revisions\/651"}],"wp:attachment":[{"href":"https:\/\/microregistrar.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=285"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/microregistrar.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=285"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/microregistrar.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=285"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}