How Doxycycline for STI Prevention Affects the Gut Microbiome

<!DOCTYPE html> <html lang="en" dir="ltr" prefix="og: https://ogp.me/ns#"> <head> <title>How Doxycycline for STI Prevention Affects the Gut Microbiome | UC San Francisco</title> <meta charset="utf-8" /> <meta name="description" content="A new study on doxy-PEP sheds light on whether people who are regular users become resistance to this treatment, which often serves as a “morning after” pill to prevent sexually transmitted diseases." /> <meta name="abstract" content="A new study on doxy-PEP sheds light on whether people who are regular users become resistance to this treatment, which often serves as a “morning after” pill to prevent sexually transmitted diseases." /> <link rel="canonical" href="https://www.ucsf.edu/news/2024/10/428571/how-doxycycline-sti-prevention-affects-gut-microbiome" /> <link rel="image_src" href="https://www.ucsf.edu/sites/default/files/2024-10/gut-bacteria-nih.jpg" /> <meta property="og:site_name" content="How Doxycycline for STI Prevention Affects the Gut Microbiome | UC San Francisco" /> <meta property="og:type" content="news" /> <meta property="og:url" content="https://www.ucsf.edu/news/2024/10/428571/how-doxycycline-sti-prevention-affects-gut-microbiome" /> <meta property="og:title" content="How Doxycycline for STI Prevention Affects the Gut Microbiome" /> <meta property="og:description" content="A new study on doxy-PEP sheds light on whether people who are regular users become resistance to this treatment, which often serves as a “morning after” pill to prevent sexually transmitted diseases." /> <meta property="og:image" content="https://www.ucsf.edu/sites/default/files/2024-10/gut-bacteria-nih.jpg" /> <meta property="og:image:secure_url" content="https://www.ucsf.edu/sites/default/files/2024-10/gut-bacteria-nih.jpg" /> <meta property="og:image:type" content="image/jpeg" /> <meta name="twitter:card" content="summary_large_image" /> <meta name="twitter:description" content="A new study on doxy-PEP sheds light on whether people who are regular users become resistance to this treatment, which often serves as a “morning after” pill to prevent sexually transmitted diseases." /> <meta name="twitter:site" content="@ucsf" /> <meta name="twitter:title" content="How Doxycycline for STI Prevention Affects the Gut Microbiome" /> <meta name="twitter:creator" content="@ucsf" /> <meta name="twitter:image" content="https://www.ucsf.edu/sites/default/files/2024-10/gut-bacteria-nih.jpg" /> <meta name="twitter:image:alt" content="||||" /> <meta name="google-site-verification" content="rSaM6CprJQndLnVGSxg0oZ-oB85lajeVcjE1fQzK1-I" /> <meta name="Generator" content="Drupal 10 (https://www.drupal.org)" /> <meta name="MobileOptimized" content="width" /> <meta name="HandheldFriendly" content="true" /> <meta name="viewport" content="width=device-width, initial-scale=1.0" /> <script type="application/ld+json">{ "@context": "https://schema.org", "@graph": [ { "@type": "NewsArticle", "headline": "How Doxycycline for STI Prevention Affects the Gut Microbiome", "name": "How Doxycycline for STI Prevention Affects the Gut Microbiome | UC San Francisco", "description": "A new study on doxy-PEP sheds light on whether people who are regular users become resistance to this treatment, which often serves as a “morning after” pill to prevent sexually transmitted diseases.", "image": { "@type": "ImageObject", "representativeOfPage": "True", "url": "https://www.ucsf.edu/sites/default/files/2024-10/gut-bacteria-nih.jpg", "width": "940", "height": "481" }, "datePublished": "2024-10-02T15:32:59-0700", "dateModified": "2024-10-02T15:32:59-0700", "author": { "@type": "Organization", "@id": "https://www.ucsf.edu/", "name": "University of California San Francisco", "url": "https://www.ucsf.edu/", "sameAs": "https://twitter.com/ucsf, https://www.facebook.com/ucsf, https://instagram.com/ucsf, https://www.youtube.com/ucsf, https://www.linkedin.com/school/ucsf", "logo": { "@type": "ImageObject", "representativeOfPage": "True", "url": "https://www.ucsf.edu/themes/custom/ucsf/assets/images/ucsf_logo_navy_for_google_structured_data.png", "width": "360", "height": "174" } }, "publisher": { "@type": "Organization", "@id": "https://www.ucsf.edu/", "name": "University of California San Francisco", "url": "https://www.ucsf.edu/", "sameAs": "https://twitter.com/ucsf, https://www.facebook.com/ucsf, https://instagram.com/ucsf, https://www.youtube.com/ucsf, https://www.linkedin.com/school/ucsf", "logo": { "@type": "ImageObject", "representativeOfPage": "True", "url": "https://www.ucsf.edu/themes/custom/ucsf/assets/images/ucsf_logo_navy_for_google_structured_data.png", "width": "360", "height": "174" } }, "mainEntityOfPage": "https://www.ucsf.edu/news/2024/10/428571/how-doxycycline-sti-prevention-affects-gut-microbiome" } ] }</script> <meta itemprop="acquia_lift:content_title" content="How Doxycycline for STI Prevention Affects the Gut Microbiome" /> <meta itemprop="acquia_lift:content_type" content="article" /> <meta itemprop="acquia_lift:page_type" content="node page" /> <meta itemprop="acquia_lift:language" content="en" /> <meta itemprop="acquia_lift:content_section" content="" /> <meta itemprop="acquia_lift:content_keywords" content="" /> <meta itemprop="acquia_lift:post_id" content="428571" /> <meta itemprop="acquia_lift:content_uuid" content="74d6ed14-3c1a-4e1a-92d6-b3655b01fa0f" /> <meta itemprop="acquia_lift:published_date" content="1727908379" /> <meta itemprop="acquia_lift:persona" content="" /> <meta itemprop="acquia_lift:engagement_score" content="1" /> <meta itemprop="acquia_lift:account_id" content="UCSF" /> <meta itemprop="acquia_lift:site_id" content="ucsfedu" /> <meta itemprop="acquia_lift:liftAssetsURL" content="https://builder.lift.acquia.com" /> <meta itemprop="acquia_lift:liftDecisionAPIURL" content="https://us.perz-api.cloudservices.acquia.io" /> <meta itemprop="acquia_lift:bootstrapMode" content="auto" /> <meta itemprop="acquia_lift:contentReplacementMode" content="trusted" /> <meta itemprop="acquia_lift:apiVersion" content="v3" /> <script src="https://builder.lift.acquia.com/lift.js" async></script> <link rel="icon" href="/themes/custom/ucsf/favicon.ico" type="image/vnd.microsoft.icon" /> <link rel="preload" href="/themes/custom/ucsf/fonts/GranjonLTW01-Roman.woff2" as="font" crossorigin /> <link rel="preload" href="/themes/custom/ucsf/fonts/HelveticaNeueLTW04-45Light.woff2" as="font" crossorigin /> <link rel="preload" href="/themes/custom/ucsf/fonts/HelveticaNeueLTW04-55Roman.woff2" as="font" crossorigin /> <link rel="preload" href="/themes/custom/ucsf/fonts/HelveticaNeueLTW04-56Italic.woff2" as="font" crossorigin /> <link rel="preload" href="/themes/custom/ucsf/fonts/HelveticaNeueLTW04-65Medium.woff2" as="font" crossorigin /> <link rel="preload" href="/themes/custom/ucsf/fonts/HelveticaNeueLTW06-75Bold.woff2" as="font" crossorigin /> <script src="/sites/default/files/google_tag/primary/google_tag.script.js?snbnwj" defer></script> <link rel="stylesheet" media="all" href="/sites/default/files/css/css_1M6X16-toc9kPsDUV7f1fRiXXjEbDp_DX8NYskiSeKQ.css?delta=0&language=en&theme=ucsf&include=eJxlkFFuxDAIRC_krj96IIvYbEIXm8jgpO7p691E2kb9QehpYAbiAxOZ1NA_jcLKbaaifscpSl6lYDF1CQwYOlY_4QIbSVWnEgk45DENgak81P9HN1swo9OuhtlPoOgig2q_9BlVYUZ1USr6IjUD0w-6FvXuZ5YJ2HVp1iYMMzBj7Sf-UOvDaHZqYKRGUX2qbQW-vYnbCHf1r3rLkhrjBcEXfB9eyCNtsXCHhFeiu4guB3uWAHWsZgwm67AII3nFaGFBSM88l2HZsDKsIaENDUn5s-f8GUUpeuJCQ6_AilDj4RkgyTgeCnB_HfmGv-lmsOQ" /> <link rel="stylesheet" media="all" href="/sites/default/files/css/css_d3zMBqhbzEuXhe0NGNKEjFfiJ6wRrce_6DpOq2twhpc.css?delta=1&language=en&theme=ucsf&include=eJxlkFFuxDAIRC_krj96IIvYbEIXm8jgpO7p691E2kb9QehpYAbiAxOZ1NA_jcLKbaaifscpSl6lYDF1CQwYOlY_4QIbSVWnEgk45DENgak81P9HN1swo9OuhtlPoOgig2q_9BlVYUZ1USr6IjUD0w-6FvXuZ5YJ2HVp1iYMMzBj7Sf-UOvDaHZqYKRGUX2qbQW-vYnbCHf1r3rLkhrjBcEXfB9eyCNtsXCHhFeiu4guB3uWAHWsZgwm67AII3nFaGFBSM88l2HZsDKsIaENDUn5s-f8GUUpeuJCQ6_AilDj4RkgyTgeCnB_HfmGv-lmsOQ" /> <script>if (!window.customElements) { document.write(' <script type="text/javascript" src="/modules/custom/ckeditor_y3ti_plugins/bower_components/webcomponentsjs/custom-elements-es5-adapter.js"></script>  <script src="/modules/custom/ckeditor_y3ti_plugins/bower_components/webcomponentsjs/webcomponents-loader.js?snbnwj"></script> <script src="/modules/custom/ucsf_adobe_analytics/js/ucsf-data-layer.js?snbnwj" defer></script> <script src="/modules/custom/ucsf_adobe_analytics/js/ucsf-mag-marketing-data-layer.js?snbnwj" defer></script> <script src="https://assets.adobedtm.com/db5f13cb240b/b1130ce1ceae/launch-db8f55f3e131.min.js" defer></script> </head> <body class="alias-news-2024-10-428571-how-doxycycline-sti-prevention-affects-gut-microbiome path-node page-node-type-article loading"> <a href="#main-content" class="visually-hidden focusable skip-link"> Skip to main content </a> <noscript><iframe src="https://www.googletagmanager.com/ns.html?id=GTM-TSHCJ6" height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript> <div class="dialog-off-canvas-main-canvas" data-off-canvas-main-canvas> <div class="page"> <header class="combined-header-region "> <section class="universal-header-region"> <div class="universal-header"> <p id="site-name" class="universal-header__title">University of California San Francisco</p> <a href="https://giving.ucsf.edu" class="universal-header__give">Give to UCSF</a> </div> </section> <section class="header-region"> <div class="header "> <figure class="header--logo logo"> <a class="logo__link" href="/" title="Home" rel="home"> <picture class="logo__image"> <img fetchpriority="high" class="logo__img" src="/themes/custom/ucsf/logo.svg" alt="Home" height="41" width="83"> </picture> </a> </figure> <div class="header--search menu-item"><a href="/search" role="button" class="nolink mobile-search-reveal "><span>Search</span></a> <div class="home-search__form "> <form action="/search" accept-charset="utf-8" method="get" class="search__form"> <label for="header-search" class="visually-hidden">Small screen search</label> <input type="text" name="search" id="header-search" size="32" class="home-search__form-input " value="" placeholder="Search people, places, ideas" /> <input type="submit" id="edit-submit-header" name="op" value="Search" class="home-search__form-submit "> <fieldset class="fieldset-reset"> <legend class="visually-hidden">Choose what type of search to perform</legend> <div class="search-filter"> <label for="allucsf"> <input id="allucsf" type="radio" name="filter" class="visually-hidden search-filter__radio" value="All" checked> <div class="search-filter__label"> <span class="search-filter__option"></span> <span>All UCSF</span> </div> </label> <label for="newscenter"> <input id="newscenter" type="radio" name="filter" class="visually-hidden search-filter__radio" value="News"> <div class="search-filter__label"> <span class="search-filter__option"></span> <span>UCSF News Center</span> </div> </label> </div> </fieldset> </form> </div> </div> <div class="slicknav-placeholder"></div> <nav aria-label="Main" id="block-ucsf-main-menu" class="block block-menu navigation menu--main main-menu--mobile main-nav"> <ul block="block-ucsf-main-menu" class="menu-parent-wrapper"> <li class="menu-item menu-item--expanded menu-top-level__item" > <a href="https://www.ucsf.edu/about" class="nolink" data-drupal-link-system-path="node/130301">About</a> <ul class="menu-child-wrapper"> <li class="menu-item dropdown-menu__item" > <a href="https://www.ucsf.edu/about" title="UCSF Overview" class="main-navigation__link dropdown-menu__link" data-drupal-link-system-path="node/130301">Overview</a> </li> <li class="menu-item dropdown-menu__item" > <a href="https://www.ucsf.edu/about/mission-and-values" class="main-navigation__link dropdown-menu__link" data-drupal-link-system-path="node/406481">Mission & Values</a> </li> <li class="menu-item menu-item--expanded dropdown-menu__item" > <span class="main-navigation__link dropdown-menu__link">Our Impact</span> <ul class="menu-child-wrapper"> <li class="menu-item dropdown-menu__item" > <a href="https://www.ucsf.edu/about/achievements" class="main-navigation__link dropdown-menu__link" data-drupal-link-system-path="node/413636">Achievements</a> </li> <li class="menu-item dropdown-menu__item" > <a href="/about/community-benefits" class="main-navigation__link dropdown-menu__link" data-drupal-link-system-path="taxonomy/term/629">UCSF in the Community</a> </li> </ul> <div class="universal-header__give-mobile"> <a class="universal-header__give" href="https://giving.ucsf.edu">Give to UCSF</a> </div> </li> <li class="menu-item dropdown-menu__item" > <a href="https://www.ucsf.edu/about/history-1" class="main-navigation__link dropdown-menu__link" data-drupal-link-system-path="node/93484">History</a> </li> <li class="menu-item menu-item--expanded dropdown-menu__item" > <span class="main-navigation__link dropdown-menu__link">Facts & Figures</span> <ul class="menu-child-wrapper"> <li class="menu-item dropdown-menu__item" > <a href="https://www.ucsf.edu/about/ucsf-budget" class="main-navigation__link dropdown-menu__link" data-drupal-link-system-path="node/403036">Budget</a> </li> <li class="menu-item dropdown-menu__item" > <a href="https://www.ucsf.edu/about/innovation" class="main-navigation__link dropdown-menu__link" data-drupal-link-system-path="node/413691">Inventions & Entrepreneurship</a> </li> <li class="menu-item dropdown-menu__item" > <a href="/sites/default/files/2024-03/UCSF-General-Fact-Sheet-March-2024.pdf" class="main-navigation__link dropdown-menu__link">UCSF Fact Sheet</a> </li> </ul> <div class="universal-header__give-mobile"> <a class="universal-header__give" href="https://giving.ucsf.edu">Give to UCSF</a> </div> </li> <li class="menu-item menu-item--expanded dropdown-menu__item" > <span class="main-navigation__link dropdown-menu__link">Administration</span> <ul class="menu-child-wrapper"> <li class="menu-item dropdown-menu__item" > <a href="https://chancellor.ucsf.edu/leadership/chancellors-cabinet" target="_blank">Campus Leaders</a> </li> <li class="menu-item dropdown-menu__item" > <a href="https://chancellor.ucsf.edu/chancellor" class="main-navigation__link dropdown-menu__link">Chancellor</a> </li> <li class="menu-item dropdown-menu__item" > <a href="https://evcprovost.ucsf.edu/" class="main-navigation__link dropdown-menu__link">Executive Vice Chancellor & Provost</a> </li> <li class="menu-item dropdown-menu__item" > <a href="/cgr" class="main-navigation__link dropdown-menu__link" data-drupal-link-system-path="node/93347">Community & Government Relations</a> </li> <li class="menu-item dropdown-menu__item" > <a href="https://diversity.ucsf.edu/" class="main-navigation__link dropdown-menu__link">Diversity & Outreach</a> </li> <li class="menu-item dropdown-menu__item" > <a href="https://fas.ucsf.edu/" class="main-navigation__link dropdown-menu__link">Finance & Administrative Services</a> </li> <li class="menu-item dropdown-menu__item" > <a href="https://legal.ucsf.edu/" class="main-navigation__link dropdown-menu__link">Legal Affairs</a> </li> <li class="menu-item dropdown-menu__item" > <a href="https://www.ucsf.edu/office-of-communications" class="main-navigation__link dropdown-menu__link" data-drupal-link-system-path="node/423371">Office of Communications</a> </li> <li class="menu-item dropdown-menu__item" > <a href="https://giving.ucsf.edu/" class="main-navigation__link dropdown-menu__link">University Development & Alumni Relations</a> </li> </ul> <div class="universal-header__give-mobile"> <a class="universal-header__give" href="https://giving.ucsf.edu">Give to UCSF</a> </div> </li> <li class="menu-item dropdown-menu__item" > <a href="https://www.ucsf.edu/about/locations" class="main-navigation__link dropdown-menu__link" data-drupal-link-system-path="node/96416">Locations</a> </li> </ul> <div class="universal-header__give-mobile"> <a class="universal-header__give" href="https://giving.ucsf.edu">Give to UCSF</a> </div> </li> <li class="menu-item menu-item--expanded menu-top-level__item" > <a href="https://www.ucsf.edu/patient-care" class="nolink" data-drupal-link-system-path="node/130356">Patient Care</a> <ul class="menu-child-wrapper"> <li class="menu-item dropdown-menu__item" > <a href="https://www.ucsf.edu/patient-care" title="Patient Care Overview" class="main-navigation__link dropdown-menu__link" data-drupal-link-system-path="node/130356">Overview</a> </li> <li class="menu-item dropdown-menu__item" > <a href="https://www.ucsfhealth.org/" class="main-navigation__link dropdown-menu__link">UCSF Health</a> </li> <li class="menu-item dropdown-menu__item" > <a href="https://www.ucsfbenioffchildrens.org/" class="main-navigation__link dropdown-menu__link">UCSF Benioff Children’s Hospitals</a> </li> <li class="menu-item dropdown-menu__item" > <a href="https://www.ucsfdentalcenter.org/" class="main-navigation__link dropdown-menu__link">UCSF Dental Center</a> </li> <li class="menu-item dropdown-menu__item" > <a href="https://psych.ucsf.edu/lpphc" class="main-navigation__link dropdown-menu__link">Langley Porter Psychiatric Hospital and Clinics</a> </li> <li class="menu-item dropdown-menu__item" > <a href="https://www.ucsfhealth.org/clinics" class="main-navigation__link dropdown-menu__link">Specialty Clinics</a> </li> <li class="menu-item dropdown-menu__item" > <a href="https://www.ucsf.edu/patient-care/clinical-trials" class="main-navigation__link dropdown-menu__link" data-drupal-link-system-path="node/93456">Clinical Trials</a> </li> </ul> <div class="universal-header__give-mobile"> <a class="universal-header__give" href="https://giving.ucsf.edu">Give to UCSF</a> </div> </li> <li class="menu-item menu-item--expanded menu-top-level__item" > <a href="https://www.ucsf.edu/research" class="nolink" data-drupal-link-system-path="node/130351">Research</a> <ul class="menu-child-wrapper"> <li class="menu-item dropdown-menu__item" > <a href="https://www.ucsf.edu/research" title="Research Overview" class="main-navigation__link dropdown-menu__link" data-drupal-link-system-path="node/130351">Overview</a> </li> <li class="menu-item dropdown-menu__item" > <a href="https://www.ucsf.edu/research/partnerships" class="main-navigation__link dropdown-menu__link" data-drupal-link-system-path="node/130491">Partnerships</a> </li> <li class="menu-item dropdown-menu__item" > <a href="https://research.ucsf.edu" class="main-navigation__link dropdown-menu__link">Office of Research</a> </li> <li class="menu-item dropdown-menu__item" > <a href="https://innovation.ucsf.edu/" class="main-navigation__link dropdown-menu__link">Innovation Ventures</a> </li> <li class="menu-item dropdown-menu__item" > <a href="https://postdocs.ucsf.edu/" class="main-navigation__link dropdown-menu__link">Postdoctoral Scholars</a> </li> </ul> <div class="universal-header__give-mobile"> <a class="universal-header__give" href="https://giving.ucsf.edu">Give to UCSF</a> </div> </li> <li class="menu-item menu-item--expanded menu-top-level__item" > <a href="https://www.ucsf.edu/education" class="nolink" data-drupal-link-system-path="node/130311">Education</a> <ul class="menu-child-wrapper"> <li class="menu-item dropdown-menu__item" > <a href="https://www.ucsf.edu/education" title="Education Overview" class="main-navigation__link dropdown-menu__link" data-drupal-link-system-path="node/130311">Overview</a> </li> <li class="menu-item dropdown-menu__item" > <a href="https://www.ucsf.edu/education/admissions" class="main-navigation__link dropdown-menu__link" data-drupal-link-system-path="node/409171">Admissions</a> </li> <li class="menu-item menu-item--expanded dropdown-menu__item" > <span class="main-navigation__link dropdown-menu__link">Schools & Programs</span> <ul class="menu-child-wrapper"> <li class="menu-item dropdown-menu__item" > <a href="http://dentistry.ucsf.edu/" title="School of Dentistry" class="main-navigation__link dropdown-menu__link">School of Dentistry</a> </li> <li class="menu-item dropdown-menu__item" > <a href="https://medschool.ucsf.edu" title="School of Medicine" class="main-navigation__link dropdown-menu__link">School of Medicine</a> </li> <li class="menu-item dropdown-menu__item" > <a href="https://pharmacy.ucsf.edu" title="School Pharmacy" class="main-navigation__link dropdown-menu__link">School of Pharmacy</a> </li> <li class="menu-item dropdown-menu__item" > <a href="https://nursing.ucsf.edu" title="School of Nursing" class="main-navigation__link dropdown-menu__link">School of Nursing</a> </li> <li class="menu-item dropdown-menu__item" > <a href="https://graduate.ucsf.edu" title="Graduate Education" class="main-navigation__link dropdown-menu__link">Graduate Division</a> </li> <li class="menu-item dropdown-menu__item" > <a href="https://globalhealthsciences.ucsf.edu" title="Global Health Sciences" class="main-navigation__link dropdown-menu__link">Global Health Sciences</a> </li> </ul> <div class="universal-header__give-mobile"> <a class="universal-header__give" href="https://giving.ucsf.edu">Give to UCSF</a> </div> </li> <li class="menu-item menu-item--expanded dropdown-menu__item" > <span class="main-navigation__link dropdown-menu__link">Resources for Students</span> <ul class="menu-child-wrapper"> <li class="menu-item dropdown-menu__item" > <a href="https://registrar.ucsf.edu/academic-calendar" class="main-navigation__link dropdown-menu__link">Academic Calendar</a> </li> <li class="menu-item dropdown-menu__item" > <a href="https://career.ucsf.edu/" class="main-navigation__link dropdown-menu__link">Career Center</a> </li> <li class="menu-item dropdown-menu__item" > <a href="https://finaid.ucsf.edu/" class="main-navigation__link dropdown-menu__link">Financial Aid</a> </li> <li class="menu-item dropdown-menu__item" > <a href="https://catalog.ucsf.edu/" class="main-navigation__link dropdown-menu__link">General Catalog</a> </li> <li class="menu-item dropdown-menu__item" > <a href="https://www.library.ucsf.edu/" class="main-navigation__link dropdown-menu__link">Library</a> </li> <li class="menu-item dropdown-menu__item" > <a href="https://registrar.ucsf.edu/" class="main-navigation__link dropdown-menu__link">Registrar</a> </li> <li class="menu-item dropdown-menu__item" > <a href="https://success.ucsf.edu/" class="main-navigation__link dropdown-menu__link">Student Success Guide</a> </li> </ul> <div class="universal-header__give-mobile"> <a class="universal-header__give" href="https://giving.ucsf.edu">Give to UCSF</a> </div> </li> </ul> <div class="universal-header__give-mobile"> <a class="universal-header__give" href="https://giving.ucsf.edu">Give to UCSF</a> </div> </li> <li class="menu-item menu-item--expanded menu-top-level__item" > <a href="https://www.ucsf.edu/news" class="nolink" data-drupal-link-system-path="node/413561">News & Media</a> <ul class="menu-child-wrapper"> <li class="menu-item dropdown-menu__item" > <a href="https://www.ucsf.edu/news" class="main-navigation__link dropdown-menu__link" data-drupal-link-system-path="node/413561">UCSF News Center</a> </li> <li class="menu-item dropdown-menu__item" > <a href="https://magazine.ucsf.edu/magazine" class="main-navigation__link dropdown-menu__link" data-drupal-link-system-path="node/418411">UCSF Magazine</a> </li> <li class="menu-item dropdown-menu__item" > <a href="/campus-news" class="main-navigation__link dropdown-menu__link" data-drupal-link-system-path="taxonomy/term/1006">Campus News</a> </li> <li class="menu-item dropdown-menu__item" > <a href="/news/media-coverage" class="main-navigation__link dropdown-menu__link" data-drupal-link-system-path="taxonomy/term/413496">Media Coverage</a> </li> <li class="menu-item dropdown-menu__item" > <a href="https://www.ucsf.edu/news-media/journalists" class="main-navigation__link dropdown-menu__link" data-drupal-link-system-path="node/130226">Resources for Journalists</a> </li> </ul> <div class="universal-header__give-mobile"> <a class="universal-header__give" href="https://giving.ucsf.edu">Give to UCSF</a> </div> </li> <li class="menu-item search menu-top-level__item" > <a href="/search" class="main-navigation__link" data-drupal-link-system-path="search">Search</a> </li> </ul> <div class="universal-header__give-mobile"> <a class="universal-header__give" href="https://giving.ucsf.edu">Give to UCSF</a> </div> </nav> <nav aria-label="Main" id="block-ucsf-main-menu-desktop" class="block block-menu navigation menu--main main-nav"> <ul block="block-ucsf-main-menu-desktop" class="main-nav__menu"> <li class="menu-item menu-item--expanded main-nav__submenu-wrapper" > <button class="main-nav__toggle menu-item-about-menu" aria-controls="aria-about-menu" aria-expanded=false > About </button> <div id="aria-about-menu" aria-labelledby="aria-label-about-menu" class="main-submenu main-submenu--0" data-level="level-0"> <button class="menu-item-close" aria-controls="aria-about-menu" aria-expanded=false> Close About menu. </button> <div data-section="section-about-menu" class="main-submenu__label main-submenu__label--0"> <span id="aria-label-about-menu" class="main-submenu__label-text">About</span> </div> <ul class="main-submenu__menu"> <li class="menu-item" > <a href="https://www.ucsf.edu/about" title="UCSF Overview" data-drupal-link-system-path="node/130301"> <span>Overview</span> </a> </li> <li class="menu-item" > <a href="https://www.ucsf.edu/about/mission-and-values" data-drupal-link-system-path="node/406481"> <span>Mission & Values</span> </a> </li> <li class="menu-item menu-item--expanded" > <button class="main-submenu__toggle menu-item-our-impact" aria-controls="aria-our-impact" aria-expanded=false > Our Impact </button> <span class="fas fa-angle-right"></span> <div id="aria-our-impact" aria-labelledby="aria-label-our-impact" class="main-submenu main-submenu--1" data-level="level-1"> <div data-section="section-our-impact" class="main-submenu__label"> <span id="aria-label-our-impact" class="main-submenu__label-text">Our Impact</span> </div> <ul class="main-submenu__menu"> <li class="menu-item" > <a href="https://www.ucsf.edu/about/achievements" data-drupal-link-system-path="node/413636"> <span>Achievements</span> </a> </li> <li class="menu-item" > <a href="/about/community-benefits" data-drupal-link-system-path="taxonomy/term/629"> <span>UCSF in the Community</span> </a> </li> </ul> </div> </li> <li class="menu-item" > <a href="https://www.ucsf.edu/about/history-1" data-drupal-link-system-path="node/93484"> <span>History</span> </a> </li> <li class="menu-item menu-item--expanded" > <button class="main-submenu__toggle menu-item-facts--figures" aria-controls="aria-facts--figures" aria-expanded=false > Facts & Figures </button> <span class="fas fa-angle-right"></span> <div id="aria-facts--figures" aria-labelledby="aria-label-facts--figures" class="main-submenu main-submenu--1" data-level="level-1"> <div data-section="section-facts--figures" class="main-submenu__label"> <span id="aria-label-facts--figures" class="main-submenu__label-text">Facts & Figures</span> </div> <ul class="main-submenu__menu"> <li class="menu-item" > <a href="https://www.ucsf.edu/about/ucsf-budget" data-drupal-link-system-path="node/403036"> <span>Budget</span> </a> </li> <li class="menu-item" > <a href="https://www.ucsf.edu/about/innovation" data-drupal-link-system-path="node/413691"> <span>Inventions & Entrepreneurship</span> </a> </li> <li class="menu-item" > <a href="/sites/default/files/2024-03/UCSF-General-Fact-Sheet-March-2024.pdf"> <span>UCSF Fact Sheet</span> </a> </li> </ul> </div> </li> <li class="menu-item menu-item--expanded" > <button class="main-submenu__toggle menu-item-administration" aria-controls="aria-administration" aria-expanded=false > Administration </button> <span class="fas fa-angle-right"></span> <div id="aria-administration" aria-labelledby="aria-label-administration" class="main-submenu main-submenu--1" data-level="level-1"> <div data-section="section-administration" class="main-submenu__label"> <span id="aria-label-administration" class="main-submenu__label-text">Administration</span> </div> <ul class="main-submenu__menu"> <li class="menu-item" > <a href="https://chancellor.ucsf.edu/leadership/chancellors-cabinet"> <span>Campus Leaders</span> </a> </li> <li class="menu-item" > <a href="https://chancellor.ucsf.edu/chancellor"> <span>Chancellor</span> </a> </li> <li class="menu-item" > <a href="https://evcprovost.ucsf.edu/"> <span>Executive Vice Chancellor & Provost</span> </a> </li> <li class="menu-item" > <a href="/cgr" data-drupal-link-system-path="node/93347"> <span>Community & Government Relations</span> </a> </li> <li class="menu-item" > <a href="https://diversity.ucsf.edu/"> <span>Diversity & Outreach</span> </a> </li> <li class="menu-item" > <a href="https://fas.ucsf.edu/"> <span>Finance & Administrative Services</span> </a> </li> <li class="menu-item" > <a href="https://legal.ucsf.edu/"> <span>Legal Affairs</span> </a> </li> <li class="menu-item" > <a href="https://www.ucsf.edu/office-of-communications" data-drupal-link-system-path="node/423371"> <span>Office of Communications</span> </a> </li> <li class="menu-item" > <a href="https://giving.ucsf.edu/"> <span>University Development & Alumni Relations</span> </a> </li> </ul> </div> </li> <li class="menu-item" > <a href="https://www.ucsf.edu/about/locations" data-drupal-link-system-path="node/96416"> <span>Locations</span> </a> </li> </ul> </div> </li> <li class="menu-item menu-item--expanded main-nav__submenu-wrapper" > <button class="main-nav__toggle menu-item-patient-care" aria-controls="aria-patient-care" aria-expanded=false > Patient Care </button> <div id="aria-patient-care" aria-labelledby="aria-label-patient-care" class="main-submenu main-submenu--0" data-level="level-0"> <button class="menu-item-close" aria-controls="aria-patient-care" aria-expanded=false> Close Patient Care menu. </button> <div data-section="section-patient-care" class="main-submenu__label main-submenu__label--0"> <span id="aria-label-patient-care" class="main-submenu__label-text">Patient Care</span> </div> <ul class="main-submenu__menu"> <li class="menu-item" > <a href="https://www.ucsf.edu/patient-care" title="Patient Care Overview" data-drupal-link-system-path="node/130356"> <span>Overview</span> </a> </li> <li class="menu-item" > <a href="https://www.ucsfhealth.org/"> <span>UCSF Health</span> </a> </li> <li class="menu-item" > <a href="https://www.ucsfbenioffchildrens.org/"> <span>UCSF Benioff Children’s Hospitals</span> </a> </li> <li class="menu-item" > <a href="https://www.ucsfdentalcenter.org/"> <span>UCSF Dental Center</span> </a> </li> <li class="menu-item" > <a href="https://psych.ucsf.edu/lpphc"> <span>Langley Porter Psychiatric Hospital and Clinics</span> </a> </li> <li class="menu-item" > <a href="https://www.ucsfhealth.org/clinics"> <span>Specialty Clinics</span> </a> </li> <li class="menu-item" > <a href="https://www.ucsf.edu/patient-care/clinical-trials" data-drupal-link-system-path="node/93456"> <span>Clinical Trials</span> </a> </li> </ul> </div> </li> <li class="menu-item menu-item--expanded main-nav__submenu-wrapper" > <button class="main-nav__toggle menu-item-research" aria-controls="aria-research" aria-expanded=false > Research </button> <div id="aria-research" aria-labelledby="aria-label-research" class="main-submenu main-submenu--0" data-level="level-0"> <button class="menu-item-close" aria-controls="aria-research" aria-expanded=false> Close Research menu. </button> <div data-section="section-research" class="main-submenu__label main-submenu__label--0"> <span id="aria-label-research" class="main-submenu__label-text">Research</span> </div> <ul class="main-submenu__menu"> <li class="menu-item" > <a href="https://www.ucsf.edu/research" title="Research Overview" data-drupal-link-system-path="node/130351"> <span>Overview</span> </a> </li> <li class="menu-item" > <a href="https://www.ucsf.edu/research/partnerships" data-drupal-link-system-path="node/130491"> <span>Partnerships</span> </a> </li> <li class="menu-item" > <a href="https://research.ucsf.edu"> <span>Office of Research</span> </a> </li> <li class="menu-item" > <a href="https://innovation.ucsf.edu/"> <span>Innovation Ventures</span> </a> </li> <li class="menu-item" > <a href="https://postdocs.ucsf.edu/"> <span>Postdoctoral Scholars</span> </a> </li> </ul> </div> </li> <li class="menu-item menu-item--expanded main-nav__submenu-wrapper" > <button class="main-nav__toggle menu-item-education" aria-controls="aria-education" aria-expanded=false > Education </button> <div id="aria-education" aria-labelledby="aria-label-education" class="main-submenu main-submenu--0" data-level="level-0"> <button class="menu-item-close" aria-controls="aria-education" aria-expanded=false> Close Education menu. </button> <div data-section="section-education" class="main-submenu__label main-submenu__label--0"> <span id="aria-label-education" class="main-submenu__label-text">Education</span> </div> <ul class="main-submenu__menu"> <li class="menu-item" > <a href="https://www.ucsf.edu/education" title="Education Overview" data-drupal-link-system-path="node/130311"> <span>Overview</span> </a> </li> <li class="menu-item" > <a href="https://www.ucsf.edu/education/admissions" data-drupal-link-system-path="node/409171"> <span>Admissions</span> </a> </li> <li class="menu-item menu-item--expanded" > <button class="main-submenu__toggle menu-item-schools--programs" aria-controls="aria-schools--programs" aria-expanded=false > Schools & Programs </button> <span class="fas fa-angle-right"></span> <div id="aria-schools--programs" aria-labelledby="aria-label-schools--programs" class="main-submenu main-submenu--1" data-level="level-1"> <div data-section="section-schools--programs" class="main-submenu__label"> <span id="aria-label-schools--programs" class="main-submenu__label-text">Schools & Programs</span> </div> <ul class="main-submenu__menu"> <li class="menu-item" > <a href="http://dentistry.ucsf.edu/" title="School of Dentistry"> <span>School of Dentistry</span> </a> </li> <li class="menu-item" > <a href="https://medschool.ucsf.edu" title="School of Medicine"> <span>School of Medicine</span> </a> </li> <li class="menu-item" > <a href="https://pharmacy.ucsf.edu" title="School Pharmacy"> <span>School of Pharmacy</span> </a> </li> <li class="menu-item" > <a href="https://nursing.ucsf.edu" title="School of Nursing"> <span>School of Nursing</span> </a> </li> <li class="menu-item" > <a href="https://graduate.ucsf.edu" title="Graduate Education"> <span>Graduate Division</span> </a> </li> <li class="menu-item" > <a href="https://globalhealthsciences.ucsf.edu" title="Global Health Sciences"> <span>Global Health Sciences</span> </a> </li> </ul> </div> </li> <li class="menu-item menu-item--expanded" > <button class="main-submenu__toggle menu-item-resources-for-students" aria-controls="aria-resources-for-students" aria-expanded=false > Resources for Students </button> <span class="fas fa-angle-right"></span> <div id="aria-resources-for-students" aria-labelledby="aria-label-resources-for-students" class="main-submenu main-submenu--1" data-level="level-1"> <div data-section="section-resources-for-students" class="main-submenu__label"> <span id="aria-label-resources-for-students" class="main-submenu__label-text">Resources for Students</span> </div> <ul class="main-submenu__menu"> <li class="menu-item" > <a href="https://registrar.ucsf.edu/academic-calendar"> <span>Academic Calendar</span> </a> </li> <li class="menu-item" > <a href="https://career.ucsf.edu/"> <span>Career Center</span> </a> </li> <li class="menu-item" > <a href="https://finaid.ucsf.edu/"> <span>Financial Aid</span> </a> </li> <li class="menu-item" > <a href="https://catalog.ucsf.edu/"> <span>General Catalog</span> </a> </li> <li class="menu-item" > <a href="https://www.library.ucsf.edu/"> <span>Library</span> </a> </li> <li class="menu-item" > <a href="https://registrar.ucsf.edu/"> <span>Registrar</span> </a> </li> <li class="menu-item" > <a href="https://success.ucsf.edu/"> <span>Student Success Guide</span> </a> </li> </ul> </div> </li> </ul> </div> </li> <li class="menu-item menu-item--expanded main-nav__submenu-wrapper" > <button class="main-nav__toggle menu-item-news--media" aria-controls="aria-news--media" aria-expanded=false > News & Media </button> <div id="aria-news--media" aria-labelledby="aria-label-news--media" class="main-submenu main-submenu--0" data-level="level-0"> <button class="menu-item-close" aria-controls="aria-news--media" aria-expanded=false> Close News & Media menu. </button> <div data-section="section-news--media" class="main-submenu__label main-submenu__label--0"> <span id="aria-label-news--media" class="main-submenu__label-text">News & Media</span> </div> <ul class="main-submenu__menu"> <li class="menu-item" > <a href="https://www.ucsf.edu/news" data-drupal-link-system-path="node/413561"> <span>UCSF News Center</span> </a> </li> <li class="menu-item" > <a href="https://magazine.ucsf.edu/magazine" data-drupal-link-system-path="node/418411"> <span>UCSF Magazine</span> </a> </li> <li class="menu-item" > <a href="/campus-news" data-drupal-link-system-path="taxonomy/term/1006"> <span>Campus News</span> </a> </li> <li class="menu-item" > <a href="/news/media-coverage" data-drupal-link-system-path="taxonomy/term/413496"> <span>Media Coverage</span> </a> </li> <li class="menu-item" > <a href="https://www.ucsf.edu/news-media/journalists" data-drupal-link-system-path="node/130226"> <span>Resources for Journalists</span> </a> </li> </ul> </div> </li> <li class="menu-item search" > <button class="main-nav__toggle menu-item-search-menu" aria-controls="aria-search-menu" aria-expanded=false > Open or Close Search Form </button> <div id="aria-search-menu" class="main-submenu main-nav__search"> <div class="home-search__form"> <form action="/search" accept-charset="utf-8" method="get" class="search__form"> <label for="header-desktop-search" class="visually-hidden">search</label> <input type="text" name="search" id="header-desktop-search" size="32" class="home-search__form-input" value="" placeholder="Search people, places, ideas" /> <fieldset class="fieldset-reset"> <legend class="visually-hidden">Choose what type of search to perform</legend> <div class="search-filter"> <label> <input type="radio" name="filter" class="visually-hidden search-filter__radio" value="All" checked> <div class="search-filter__label"> <span class="search-filter__option"></span> <span>All UCSF</span> </div> </label> <label> <input type="radio" name="filter" class="visually-hidden search-filter__radio" value="News"> <div class="search-filter__label"> <span class="search-filter__option"></span> <span>UCSF News Center</span> </div> </label> </div> </fieldset> <input type="submit" id="edit-submit" name="op" value="Search" class="home-search__form-submit"> </form> </div> </div> </li> </ul> </nav> </div> </section> </header> <div class="help"> <div class="region-highlighted"> <div data-drupal-messages-fallback class="hidden"></div> </div> </div> <div class="region-content"> <div id="block-ucsf-content" class="block block-system block-system-main-block"> <main class="main "> <a id="main-content" tabindex="-1"></a> <figure data-history-node-id="428571" class="article-medium-banner"> <figure> <picture class="field field-banner-image field--type-entity-reference field--label-hidden field__item"> <source srcset="/sites/default/files/styles/article_feature_banner__image/public/2024-10/gut-bacteria-nih.jpg 1x, /sites/default/files/styles/feature_banner_2x/public/2024-10/gut-bacteria-nih.jpg 2x" media="all and (min-width: 1280px)" type="image/jpeg" width="1440" height="780"/> <source srcset="/sites/default/files/styles/feature_banner_large/public/2024-10/gut-bacteria-nih.jpg 1x, /sites/default/files/styles/feature_banner_2x/public/2024-10/gut-bacteria-nih.jpg 2x" media="all and (min-width: 1050px) and (max-width: 1280px)" type="image/jpeg" width="1280" height="693"/> <source srcset="/sites/default/files/styles/feature_banner_medium/public/2024-10/gut-bacteria-nih.jpg 1x, /sites/default/files/styles/feature_banner_medium_2x/public/2024-10/gut-bacteria-nih.jpg 2x" media="all and (min-width: 850px) and (max-width: 1049px)" type="image/jpeg" width="1050" height="569"/> <source srcset="/sites/default/files/styles/feature_banner_narrow/public/2024-10/gut-bacteria-nih.jpg 1x, /sites/default/files/styles/feature_banner_narrow_2x/public/2024-10/gut-bacteria-nih.jpg 2x" media="all and (min-width: 769px) and (max-width: 849px)" type="image/jpeg" width="850" height="460"/> <source srcset="/sites/default/files/styles/feature_banner_small/public/2024-10/gut-bacteria-nih.jpg 1x, /sites/default/files/styles/feature_banner_small_2x/public/2024-10/gut-bacteria-nih.jpg 2x" media="all and (max-width: 768px)" type="image/jpeg" width="769" height="417"/> <source srcset="/sites/default/files/styles/featur_banner_x_small/public/2024-10/gut-bacteria-nih.jpg 1x, /sites/default/files/styles/featur_banner_x_small_2x/public/2024-10/gut-bacteria-nih.jpg 2x" media="all and (max-width: 599px)" type="image/jpeg" width="600" height="325"/> <img loading="eager" src="/sites/default/files/styles/article_feature_banner__image/public/2024-10/gut-bacteria-nih.jpg" width="1440" height="780" alt="A microscopic image of bacteria in the microbiome of the gut." class="element-fade"/> </picture> </figure> </figure> <div class="main-content narrow-page"> <header class="article-header article-medium-header"> <ul class="article-header__byline"> <li class="article-header__primary-area" data-primary-area="pa-research">Research</li> <li class="article-header__date"> <div class="field field-date-and-time field--type-datetime field--label-hidden field__item"><time datetime="2024-10-03T09:00:00Z" class="datetime"> October 3, 2024 </time> </div> </li> </ul> <h1><span class="field field--name-title field--type-string field--label-hidden">How Doxycycline for STI Prevention Affects the Gut Microbiome</span> </h1> <h2 class="field field-sub-title field--type-text field--label-hidden article-header__subheading">New study shows frequent doxy-PEP users maintained gastrointestinal health, although antibiotic-resistant bacteria increased – which might, over time, lessen treatment effectiveness.</h2> <p class="article-header__author"> By <a href="https://www.ucsf.edu/bio/victoria-colliver">Victoria Colliver</a> <span class="article-art-credit">Banner: Microscopic image of bacteria in the gut. Image by Donny Bliss, NIH</span> </p> </header> <ul class="article-meta-share"> <li><a rel="nofollow" href="https://www.facebook.com/share.php?u=https://www.ucsf.edu/news/2024/10/428571/how-doxycycline-sti-prevention-affects-gut-microbiome" target="_blank" title="Share on Facebook"><span class="fab fa-facebook-square"></span> <span class="indent-text">Share on Facebook</span></a></li> <li><a rel="nofollow" href="https://www.twitter.com/share?text=How Doxycycline for STI Prevention Affects the Gut Microbiome&url=https://www.ucsf.edu/news/2024/10/428571/how-doxycycline-sti-prevention-affects-gut-microbiome" target="_blank" title="Share on Twitter"><span class="fa-brands fa-square-x-twitter"></span> <span class="indent-text">Share on Twitter</span></a></li> <li><a rel="nofollow" href="https://www.reddit.com/submit?url=https://www.ucsf.edu/news/2024/10/428571/how-doxycycline-sti-prevention-affects-gut-microbiome&title=How Doxycycline for STI Prevention Affects the Gut Microbiome" target="_blank" title="Share on Reddit"><span class="fab fa-reddit-square"></span> <span class="indent-text">Share on Reddit</span></a></li> <li><a rel="nofollow" href="/cdn-cgi/l/email-protection#c9f6bda6f4efbabcaba3acaabdf48fbba6a4e99c8a9a8fe987acbebaf3e981a6bee98da6b1b0aab0aaa5a0a7ace9afa6bbe99a9d80e999bbacbfaca7bda0a6a7e988afafacaabdbae9bda1ace98ebcbde984a0aabba6aba0a6a4acefaba6adb0f481a6bee98da6b1b0aab0aaa5a0a7ace9afa6bbe99a9d80e999bbacbfaca7bda0a6a7e988afafacaabdbae9bda1ace98ebcbde984a0aabba6aba0a6a4acecf98decf988ecf98decf98888e9a7acbee9babdbcadb0e9a6a7e9ada6b1b0e4998c99e9baa1acadbae9a5a0aea1bde9a6a7e9bea1acbda1acbbe9b9aca6b9a5ace9bea1a6e9a8bbace9bbacaebca5a8bbe9bcbaacbbbae9abacaaa6a4ace9bbacbaa0babda8a7aaace9bda6e9bda1a0bae9bdbbaca8bda4aca7bde5e9bea1a0aaa1e9a6afbdaca7e9baacbbbfacbae9a8bae9a8e92b4955a4a6bba7a0a7aee9a8afbdacbb2b4954e9b9a0a5a5e9bda6e9b9bbacbfaca7bde9baacb1bca8a5a5b0e9bdbba8a7baa4a0bdbdacade9ada0baaca8baacbae7e9e9ecf98decf988ecf98decf988a1bdbdb9baf3e6e6bebebee7bcaabaafe7acadbce6a7acbebae6fbf9fbfde6f8f9e6fdfbf1fcfef8e6a1a6bee4ada6b1b0aab0aaa5a0a7ace4babda0e4b9bbacbfaca7bda0a6a7e4a8afafacaabdbae4aebcbde4a4a0aabba6aba0a6a4ac" title="Email this article"><span class="fas fa-envelope-square"></span> <span class="indent-text">Email this article</span></a></li> <li><a rel="nofollow" onclick="window.print();return false;" href="https://www.ucsf.edu/news/2024/10/428571/how-doxycycline-sti-prevention-affects-gut-microbiome" title="Print this article"><span class="fas fa-print"></span> <span class="indent-text">Print this article</span></a></li> </ul> <div class="page_narrow"><p>Taking a dose of the oral antibiotic doxycycline after a high-risk sexual encounter has dramatically reduced the incidence of sexually transmitted infections (STIs) in places where the strategy is being tried.</p> <p>Despite its effectiveness, the new strategy, known as doxy-PEP, may come with risks, especially with chronic use. Experts worry about the impact on the community of gut bacteria, also known as the microbiome, and the potential that the antibiotic will give rise to resistant strains of bacteria.</p> <p>Now, using metagenomic sequencing – techniques to analyze the total genomic material – to see the impact of doxycycline on the gut microbiome of those who took it frequently for six months, UC San Francisco researchers have found both reassurance and possible cause for concern.</p> <p>Doxy-PEP did not have much impact on the overall composition of bacterial communities in gastrointestinal tracts. But scientists noted signs of resistance building against tetracycline, the class of antibiotic that doxycycline belongs to, which could make it less effective.</p> <p>The study appears Oct. 3 in the journal <a href="https://www.nature.com/articles/s41591-024-03274-2"><em>Nature Medicine</em></a>.</p> <p>“While doxy-PEP did not appear to have global impacts on the gut microbiome, it did have impacts on the antimicrobial resistance of gut bacteria, both in terms of the proportion of tetracycline class resistance genes and the amount that were turned on, or expressed,” said <a href="https://profiles.ucsf.edu/charles.langelier">Chaz Langelier</a>, MD, PhD, an associate professor of medicine in UCSF’s Division of Infectious Diseases and senior author of the paper. “So, it’s not totally innocuous.”</p> <h2>San Francisco’s high-profile STI prevention role</h2> <p>Doxy-PEP is short for doxycycline post-exposure prophylaxis, and it involves taking two 100-milligram pills within 72 hours of condomless sex.</p> <p>Prompted by early promising clinical trial results, San Francisco became the first city in the country in October of 2022 to recommend doxy-PEP to gay and bisexual men and transgender women with a history of having unprotected encounters with multiple partners.</p> <aside class="ucsfcallout callout-right" data-image="1"> <div class="callout__image"> <div> <figure data-embed-button="media_assets" data-entity-embed-display="entity_reference:media_thumbnail" data-entity-embed-display-settings="{"image_style":"","image_link":"","image_loading":{"attribute":"lazy"},"link_url":""}" data-entity-type="media" data-entity-uuid="c03fae1f-b722-4c1d-9a19-434a18fae3c5" data-langcode="en" class="embedded-entity"><picture> <img loading="lazy" src="/sites/default/files/2023-03/pill-icon.jpg" width="928" height="928" alt="An icon illustration of a circular pill tablet." class="element-fade"> </picture></figure> </div> </div> <div class="callout__content"> <h3 class="eyebrow-title">The DOXY-PEP Treatment</h3> <p class="null">Have questions about whether doxy-PEP is right for you?</p> <p><a class="link--cta" data-entity-substitution="canonical" data-entity-type="node" data-entity-uuid="f43e89fa-c759-4015-a52d-57b78037c05f" href="https://www.ucsf.edu/news/2023/07/425786/dont-take-chances-why-doxycycline-great-bet-against-stis" title="Don’t Take Chances: Why Doxycycline is a Great Bet Against STIs">Check out our Q&A</a><br>  </p> </div> </aside> <p>In March 2024, the San Francisco Department of Public Health released results showing that after about a year, the approach halved the incidence of chlamydia and early syphilis. In June, the U.S. Centers for Disease Control and Prevention (CDC) issued guidelines recommending doxy-PEP for these groups. It was the first new STI prevention tool to be adopted in decades.</p> <p>But the widespread use of antibiotics raises concerns about resistance and the potential harmful impact on gut health, specifically the balance of bacteria and other microbes. Disruption can lead to diarrhea, nausea, fever and abdominal pain; and, until now, there had been very limited research into these side effects.</p> <p>Working with the Chan Zuckerberg Biohub and scientists in Washington and Georgia, UCSF researchers studied participants from the recent doxy-PEP clinical trial in San Francisco and Seattle, led by Annie Luetkemeyer, MD, a professor of medicine in the Division of Infectious Diseases at UCSF.</p> <p>The study included 100 individuals who used doxy-PEP and 50 individuals who received standard-of-care and did not use doxy-PEP. Researchers analyzed rectal swabs collected at enrollment and after six months to study the presence of DNA and RNA from gut bacteria and their antibiotic-resistance genes.</p> <p>“While we found no major changes to the community of gut bacteria in doxy-PEP users, we saw that doxy-PEP users over time had increasing amounts of tetracycline resistance genes present in their gut,” said <a href="https://profiles.ucsf.edu/victoria.chu">Victoria T. Chu</a>, MD, MPH, an assistant professor of pediatrics in the Division of Global Health and Infectious Diseases at UCSF and a first author of the study. “It also appeared to be dose dependent, meaning the more doxy-PEP they used, the larger the increase was.”</p> <p>More research is needed to determine which gut bacteria are turning on these tetracycline-resistant genes to know whether this will lead to more doxycycline-resistant infections among both individuals taking doxy-PEP and in the greater community.</p> <p>“Right now, it looks like the pros outweigh the cons,” Langelier said. “Especially given the dramatic rise in STIs, in particular syphilis, over the past decade.”</p> <p class="small-text"><strong>Authors:</strong> Other UCSF and Biohub authors include, Abigail Glascock, PhD, Chase Cannon, MD, MPH, Stephanie E. Cohen, MD, MPH, Katrina L. Kalantar, PhD, Ryan Ward, MS, and Christina Love, BS.</p> <p class="small-text"><strong>Funding:</strong> The work was funded by grants from the National Institutes of Health (NCT03980223), National Health, Lung and Blood Institute (R01HL155418), National Institute of Allergy and Infectious Diseases (K23AI144036, R01AI143439, R01AI143431).</p> </div> <div class="tags-menu-region"> <h3 class="tags-menu__title">Topics</h3> <ul class="tags-menu"> <li class="tags-menu__item"><a href="/topics/aids-and-hiv" hreflang="en">AIDS and HIV</a></li> <li class="tags-menu__item"><a href="/topics/gastroenterology-and-hepatology" hreflang="en">Gastroenterology and Hepatology</a></li> <li class="tags-menu__item"><a href="/topics/infectious-disease" hreflang="en">Infectious Disease</a></li> <li class="tags-menu__item"><a href="/topics/pharmacy-and-pharmacology" hreflang="en">Pharmacy and Pharmacology</a></li> <li class="tags-menu__item"><a href="/topics/public-health" hreflang="en">Public Health</a></li> <li class="tags-menu__item"><a href="/topics/reproductive-health" hreflang="en">Reproductive Health</a></li> </ul> </div> </div> </main> <aside class="recommended-articles has-recommended-article "> <div class="recommended-articles__banner"> <h2 class="recommended-articles__title">Recommended Reading</h2> <a href="https://www.ucsf.edu/news/2023/02/424861/doxycycline-sti-prevention-highly-effective-minimal-drug-resistance" class="recommended-article__link"> <div class="recommended-article__image"> <figure> <picture class="field field-card-image field--type-entity-reference field--label-hidden field__item"> <img loading="lazy" src="/sites/default/files/styles/recommended_article__image/public/2023-03/syphilis-SEM-image.jpg" width="850" height="470" alt="A scanning electron microscopic image of a cluster of sprial-shaped Treponema pallidum bacteria, which cause syphilis." class="element-fade"/> </picture> </figure> </div> <header class="recommended-article__copy"> <ul class="article-header__byline"> <li class="article-header__primary-area" data-primary-area="pa-research">Research</li> <li class="article-header__date"> <div class="field field-date-and-time field--type-datetime field--label-hidden field__item"><time datetime="2023-02-22T23:27:03Z" class="datetime"> February 22, 2023 </time> </div> </li> </ul> <h2><span class="field field--name-title field--type-string field--label-hidden">Doxycycline for STI Prevention: Highly Effective, Minimal Drug Resistance</span> </h2> </header> </a> </div> <div class="views-element-container"><div class="element-swoosh view view-articles-by-term view-id-articles_by_term view-display-id-block_1 js-view-dom-id-c035cdc524e0d0aa39342127acd9084a9685b3d14b1bd0706a4e1b67590a6e1c"> <div class="view-content"> <div class="views-row"> <article data-history-node-id="428891" class="news-card" data-primary-area="pa-research"> <a href="https://www.ucsf.edu/news/2024/11/428891/new-study-looks-why-cancer-treatments-cause-heart-damage" class="news-card__link"> <figure> <picture class="news-card-background"> <img class="element-fade" src="/themes/custom/ucsf/images/card/transparent-news-card.png" alt="Placeholder image" height="216" width="384" loading="lazy"> </picture> </figure> <header class="news-card__copy"> <ul class="article-header__byline"> <li class="article-header__primary-area" data-primary-area="pa-research">Research</li> <li class="article-header__date"> <div class="field field-date-and-time field--type-datetime field--label-hidden field__item"><time datetime="2024-11-13T16:17:10Z" class="datetime"> Nov. 13, 2024 </time> </div> </li> </ul> <h2><span class="field field--name-title field--type-string field--label-hidden">New Study Looks at Why Cancer Treatments Cause Heart Damage</span> </h2> </header> </a> </article> </div> <div class="views-row"> <article data-history-node-id="428831" class="news-card" data-primary-area="pa-research"> <a href="https://www.ucsf.edu/news/2024/11/428831/1-genomic-test-can-diagnose-nearly-any-infection" class="news-card__link"> <figure> <picture class="field field-card-image field--type-entity-reference field--label-hidden field__item"> <source srcset="/sites/default/files/styles/news_card__image/public/2024-11/charles-chiu-dna-extraction.jpg 1x, /sites/default/files/styles/news_card__image/public/2024-11/charles-chiu-dna-extraction.jpg 2x" media="all and (max-width: 599px)" type="image/jpeg" width="600" height="338"/> <img loading="lazy" src="/sites/default/files/styles/news_card__image/public/2024-11/charles-chiu-dna-extraction.jpg" width="600" height="338" alt="Researcher Charles Chiu is pictured in the reflection of a robotic machine used to extract DNA from a sample." class="element-fade"/> </picture> </figure> <header class="news-card__copy"> <ul class="article-header__byline"> <li class="article-header__primary-area" data-primary-area="pa-research">Research</li> <li class="article-header__date"> <div class="field field-date-and-time field--type-datetime field--label-hidden field__item"><time datetime="2024-11-13T01:28:53Z" class="datetime"> Nov. 12, 2024 </time> </div> </li> </ul> <h2><span class="field field--name-title field--type-string field--label-hidden">1 Genomic Test Can Diagnose Nearly Any Infection</span> </h2> </header> </a> </article> </div> <div class="views-row"> <article data-history-node-id="428756" class="news-card" data-primary-area="pa-research"> <a href="https://www.ucsf.edu/news/2024/10/428756/katherine-van-loon-named-editor-chief-jco-global-oncology" class="news-card__link"> <figure> <picture class="news-card-background"> <img class="element-fade" src="/themes/custom/ucsf/images/card/transparent-news-card.png" alt="Placeholder image" height="216" width="384" loading="lazy"> </picture> </figure> <header class="news-card__copy"> <ul class="article-header__byline"> <li class="article-header__primary-area" data-primary-area="pa-research">Research</li> <li class="article-header__date"> <div class="field field-date-and-time field--type-datetime field--label-hidden field__item"><time datetime="2024-10-31T18:15:18Z" class="datetime"> Oct. 31, 2024 </time> </div> </li> </ul> <h2><span class="field field--name-title field--type-string field--label-hidden">Katherine Van Loon Named Editor-in-Chief of JCO Global Oncology</span> </h2> </header> </a> </article> </div> </div> </div> </div> <div class="footer-ctas-wrapper"> <div class="field field-ankle-cta field--type-entity-reference field--label-hidden field__items"> <div class="field__item"> <div class="clearfix text-formatted field body field--type-text-with-summary field--label-hidden field__item"><h2>Stay in touch with the latest updates.</h2> <p><a class="icon-media" data-entity-substitution="canonical" data-entity-type="node" data-entity-uuid="cab6a11f-4158-4d04-88f1-d511d9455ca2" href="https://www.ucsf.edu/subscribe-ucsf-news" title="Subscribe to UCSF News">Subscribe to UCSF News</a></p> </div> </div> <div class="field__item"> <div class="clearfix text-formatted field body field--type-text-with-summary field--label-hidden field__item"><h2>Are you a member of the news media?</h2> <p><a class="icon-media" data-entity-substitution="canonical" data-entity-type="node" data-entity-uuid="389ec7dc-e40f-4077-9e9c-884ccbea0dec" href="https://www.ucsf.edu/news-media/journalists" title="Resources for Journalists">Visit the Media Center</a></p> </div> </div> </div> </div> </aside> </div> </div> <footer class="footer-region"> <div class="footer"> <div class="logo-follow"> <figure class="footer-logo"> <a class="footer-logo__link" href="/"> <div class="footer-logo__image"> <img class="footer-logo__img" src="/themes/custom/ucsf/images/footer-logo.svg" alt="UCSF Footer Logo" width="100" height="100"> </div> </a> </figure> <div class="follow"> <h2>Follow Us:</h2> <ul> <li class="follow-facebook"><a href="https://www.facebook.com/ucsf"><span class="fab fa-facebook-f"></span> <span class="indent-text">Facebook</span></a></li> <li class="follow-twitter"><a href="https://www.twitter.com/ucsf"><span class="fab fa-x-twitter"></span> <span class="indent-text">Twitter</span></a></li> <li class="follow-youtube"><a href="https://www.youtube.com/ucsf"><span class="fab fa-youtube"></span> <span class="indent-text">YouTube</span></a></li> <li class="follow-instagram"><a href="https://www.instagram.com/ucsf"><span class="fab fa-instagram"></span> <span class="indent-text">Instagram</span></a></li> </ul> </div> </div> <nav aria-label="Main" id="block-ucsf-footer" class="block block-menu navigation menu--footer"> <ul block="block-ucsf-footer" class="menu"> <li class="menu-item" > <a href="https://www.ucsf.edu/cgr/advocacy" data-drupal-link-system-path="node/408041">Become a UCSF Advocate</a> </li> <li class="menu-item" > <a href="https://ucsfhealth.samaritan.com">Volunteer at UCSF Medical Center</a> </li> <li class="menu-item" > <a href="https://together.ucsf.edu/">Start a Fundraiser</a> </li> <li class="menu-item" > <a href="https://www.ucsf.edu/subscribe-ucsf-news" data-drupal-link-system-path="node/403161">Subscribe to UCSF News</a> </li> </ul> </nav> <nav aria-label="Main" id="block-footer2resources" class="block block-menu navigation menu--footer2"> <ul block="block-footer2resources" class="menu"> <li class="menu-item" > <a href="https://websites.ucsf.edu/azlist">A to Z Website List</a> </li> <li class="menu-item" > <a href="https://www.ucsf.edu/accessibility-resources" data-drupal-link-system-path="node/421786">Accessibility Resources</a> </li> <li class="menu-item" > <a href="https://policies.ucsf.edu/">Administrative Policies</a> </li> <li class="menu-item" > <a href="https://identity.ucsf.edu/">Brand Guidelines</a> </li> <li class="menu-item" > <a href="https://campuslifeserviceshome.ucsf.edu/">Campus Life Services</a> </li> <li class="menu-item" > <a href="https://www.ucsf.edu/about/locations" data-drupal-link-system-path="node/96416">Campus Maps</a> </li> <li class="menu-item" > <a href="https://www.ucsf.edu/about/working-ucsf" data-drupal-link-system-path="node/409191">Careers at UCSF</a> </li> <li class="menu-item" > <a href="https://chancellor.ucsf.edu/">Chancellor</a> </li> <li class="menu-item" > <a href="https://diversity.ucsf.edu/">Diversity & Outreach</a> </li> <li class="menu-item" > <a href="https://police.ucsf.edu/emergency-preparedness">Emergency Preparedness</a> </li> <li class="menu-item" > <a href="https://hr.ucsf.edu">Human Resources</a> </li> <li class="menu-item" > <a href="https://www.library.ucsf.edu/">Library</a> </li> <li class="menu-item" > <a href="https://directory.ucsf.edu/">People Directory</a> </li> <li class="menu-item" > <a href="https://police.ucsf.edu/">Police</a> </li> <li class="menu-item" > <a href="https://campuslifeservices.ucsf.edu/transportation/services/shuttles/">Shuttle Schedule</a> </li> <li class="menu-item" > <a href="https://profiles.ucsf.edu">UCSF Profiles</a> </li> </ul> </nav> <div id="block-popwiseblock" class="block block-block-content block-block-content6efc2b33-6a3d-487d-8945-4c884ad0df82"> <div class="clearfix text-formatted field body field--type-text-with-summary field--label-hidden field__item"><script data-cfasync="false" src="/cdn-cgi/scripts/5c5dd728/cloudflare-static/email-decode.min.js"></script><script type="text/javascript" data-cfasync="false"> (function(W,i,s,e,P,o,p){W['WisePopsObject']=P;W[P]=W[P]||function(){ (W[P].q=W[P].q||[]).push(arguments)},W[P].l=1*new Date();o=i.createElement(s), p=i.getElementsByTagName(s)[0];o.async=1;o.src=e;p.parentNode.insertBefore(o,p) })(window,document,'script','//loader.wisepops.com/get-loader.js?v=1&site=dQ5haeqNrm','wisepops'); </script></div> </div> </div> <div class="footer-bottom"> <p>© 2024 The Regents of The University of California</p> <ul class="text-align: right;"> <li><a href="/sitemap.xml" style="left: -9999px; position:absolute;" tabindex="-1" aria-hidden="true">Sitemap</a></li> <li><a href="/sitemap">Site Map</a></li> <li><a href="/terms-of-use">Terms of Use</a></li> <li><a href="/feedback">Report an issue with UCSF.edu website</a></li> </ul> </div> </footer> </div> </div> <script>window.dataLayer = window.dataLayer || []; window.dataLayer.push({"drupalLanguage":"en","drupalCountry":"US","siteName":"UC San Francisco","entityCreated":"1727908379","entityLangcode":"en","entityStatus":"1","entityUid":"11011","entityUuid":"74d6ed14-3c1a-4e1a-92d6-b3655b01fa0f","entityVid":"771446","entityName":"kquintanilla","entityType":"node","entityBundle":"article","entityId":"428571","entityTitle":"How Doxycycline for STI Prevention Affects the Gut Microbiome","entityTaxonomy":{"areas":{"726":"Research"},"article_type":{"714":"Press Release"},"topics":{"609":"AIDS and HIV","642":"Gastroenterology and Hepatology","654":"Infectious Disease","678":"Pharmacy and Pharmacology","608":"Public Health","688":"Reproductive Health"}},"userUid":0});</script>  <link name="polymer_platform" href="/modules/custom/ckeditor_y3ti_plugins/elements/build.html" rel="import" /> <script type="application/json" data-drupal-selector="drupal-settings-json">{"path":{"baseUrl":"\/","pathPrefix":"","currentPath":"node\/428571","currentPathIsAdmin":false,"isFront":false,"currentLanguage":"en"},"pluralDelimiter":"\u0003","suppressDeprecationErrors":true,"ajaxPageState":{"libraries":"eJxlkFtywzAIRTekRh9dkAZLxKZBwiOQXXX1UWN30rQ_DHN4XC7xholMaujvRmHlNlNRv-MUJa9SsJi6yKDa_QSKP3lGVZhx1KSiL1IzMH2hS2DA0LH6CRfYSKo6lUjAIQ8hCEzlpv4_utiCGZ0aGKlRVJ9qW4EvT-K0q2E-7mhRrx55zBQLV0h_iGxYGdaQ0DAaSXkt6y6iy8Fmlgn4yL9DgDrUGIPJOlTDcFjHjrAgJCrzr8bTBUUpeuJCQ1iBFaHGQyBAkgkDFOD-MPaEbiPc1T_iBT7g8wVkSY3RdWnWxoIZmLH28943tT4eN98BG5qw5A","theme":"ucsf","theme_token":null},"ajaxTrustedUrl":[],"dataLayer":{"defaultLang":"en","languages":{"en":{"id":"en","name":"English","direction":"ltr","weight":0}}},"statistics":{"data":{"nid":"428571"},"url":"\/core\/modules\/statistics\/statistics.php"},"views":{"ajax_path":"\/views\/ajax","ajaxViews":{"views_dom_id:c035cdc524e0d0aa39342127acd9084a9685b3d14b1bd0706a4e1b67590a6e1c":{"view_name":"articles_by_term","view_display_id":"block_1","view_args":"609+642+654+678+608+688\/428571","view_path":"\/node\/428571","view_base_path":null,"view_dom_id":"c035cdc524e0d0aa39342127acd9084a9685b3d14b1bd0706a4e1b67590a6e1c","pager_element":0}}},"user":{"uid":0,"permissionsHash":"0c730a228c7c7fb09ef69cc49872503ed212ec963125de64d7bd9d3929d14bf0"}}</script> <script src="/sites/default/files/js/js_ChBLFJmLnJSY1j9tLrWbRTmJImKSKrgUmJ7S1dxzYdk.js?scope=footer&delta=0&language=en&theme=ucsf&include=eJxlkFFuxDAIRC_krj96IIvYbEIXm8jgpO7p691E2kb9QehpYAbiAxOZ1NA_jcLKbaaifscpSl6lYDF1CQwYOlY_4QIbSVWnEgk45DENgak81P9HN1swo9OuhtlPoOgig2q_9BlVYUZ1USr6IjUD0w-6FvXuZ5YJ2HVp1iYMMzBj7Sf-UOvDaHZqYKRGUX2qbQW-vYnbCHf1r3rLkhrjBcEXfB9eyCNtsXCHhFeiu4guB3uWAHWsZgwm67AII3nFaGFBSM88l2HZsDKsIaENDUn5s-f8GUUpeuJCQ6_AilDj4RkgyTgeCnB_HfmGv-lmsOQ"></script> <script src="https://kit.fontawesome.com/0047baebb3.js" crossorigin="anonymous"></script> <script src="/sites/default/files/js/js_DGHzI4C8s2m5srCR8I7slhej7nbVRHo8VPE5sxHlbEQ.js?scope=footer&delta=2&language=en&theme=ucsf&include=eJxlkFFuxDAIRC_krj96IIvYbEIXm8jgpO7p691E2kb9QehpYAbiAxOZ1NA_jcLKbaaifscpSl6lYDF1CQwYOlY_4QIbSVWnEgk45DENgak81P9HN1swo9OuhtlPoOgig2q_9BlVYUZ1USr6IjUD0w-6FvXuZ5YJ2HVp1iYMMzBj7Sf-UOvDaHZqYKRGUX2qbQW-vYnbCHf1r3rLkhrjBcEXfB9eyCNtsXCHhFeiu4guB3uWAHWsZgwm67AII3nFaGFBSM88l2HZsDKsIaENDUn5s-f8GUUpeuJCQ6_AilDj4RkgyTgeCnB_HfmGv-lmsOQ"></script> <script type="text/javascript"> /*<![CDATA[*/ (function() { var sz = document.createElement('script'); sz.type = 'text/javascript'; sz.async = true; sz.src = '//siteimproveanalytics.com/js/siteanalyze_8343.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(sz, s); })(); /*]]>*/ </script> </body> </html>

CINXE.COM

How Doxycycline for STI Prevention Affects the Gut Microbiome | UC San Francisco