[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"$fxLN3MUwXCdr5RPjwZYIDpOj8CHyjOmngWTgoKXPtZbg":3,"$fR__oIYMDdrZq5braWrjJWtuWdvbgJMbkXNUDL7DxZPU":32,"$f3Ft0rKFJHppdzE-vuveecxx1BUcg9iOlMLtyzf_MJDg":47},[4,8,12,16,20,24,28],{"title":5,"slug":6,"path":7},"About Microbeonline.com","about-microbeonline-com","\u002Fabout-microbeonline-com\u002F",{"title":9,"slug":10,"path":11},"About Me","about-me","\u002Fabout-microbeonline-com\u002Fabout-me\u002F",{"title":13,"slug":14,"path":15},"Advertise with Us","advertise-us","\u002Fadvertise-us\u002F",{"title":17,"slug":18,"path":19},"Privacy Policy","privacy-policy","\u002Fprivacy-policy\u002F",{"title":21,"slug":22,"path":23},"Abbreviations","abbreviations","\u002Fabbreviations\u002F",{"title":25,"slug":26,"path":27},"Microbes","microbes","\u002Fmicrobes\u002F",{"title":29,"slug":30,"path":31},"Books","recommended-books","\u002Frecommended-books\u002F",{"type":33,"data":34},"blog",{"slug":35,"title":36,"description":36,"seoTitle":37,"seoDescription":37,"author":38,"createdDate":39,"lastUpdatedDate":40,"draft":41,"category":42,"image":37,"body":43,"faq":44,"tags":45,"related":46},"mug-test-b-glucuronidase-test-for-rapid-identification-of-e-coli","MUG  (Beta-Glucuronidase) Test for E. coli",null,"Acharya Tankeshwar","2013-07-20","2025-12-29",false,"biochemical-tests","MUG is an acronym for 4-methylumbelliferyl-β-D-glucuronide. Since 97% of *Escherichia coli* strains produce the enzyme β-D-glucuronidase, MUG test can be used for rapid identification of *E. coli*. Verotoxin-producing *E. coli* (*E. coli* O157:H7) strains do not produce MUG. Please remember that some rare strains of *Salmonella, Yersinia,* and *Shigella* also produce the enzyme β-glucuronidase.\n\nBeta-D-glucuronidase is an enzyme that hydrolyzes the beta-D-glucopyranosid-uronic derivatives to aglycons and D-glucuronic acid.\n\n![E. coli use MUG as a substrate, releasing a fluorogenic compound - E. coli use MUG as a substrate, releasing a fluorogenic compound](https:\u002F\u002Fassets.microbeonline.com\u002Fblogs\u002Fmug-test.jpg)Figure: E. coli use MUG as a substrate, releasing a fluorogenic compound\n\nThe substrate 4-methylumbelliferyl-beta-D-glucuronide is impregnated in the disc and is hydrolyzed by the enzyme (beta-D-glucuronidase) to yield the 4-methylumbelliferyl moiety, which fluoresces blue under long-wavelength ultraviolet light.\n\n### Significance of MUG Test\n\nU.S. Environmental Protection Agency has approved 4-methylumbelliferyl-β-D-glucuronide *Escherichia coli* broth medium (EC-MUG) is an effective and rapid method for detection and verification of *E. coli* in food, water, and environmental samples.\n\nStandard analysis of water includes the [most probable number (MPN) ](\u002Fprobable-number-mpn-test-principle-procedure-results\u002F)for the presumptive and quantitative detection of coliform and fecal coliform bacteria in water samples. According to ASM, EC broth and agar media with MUG are best suited for confirmatory testing of the presence of [E. coli ](\u002Fe-coli-disease-properties-pathogenesis-and-laboratory-diagnosis\u002F)after a presumptive positive result for fecal coliform bacteria.\n\nMUG test can be used to separate potential verotoxin-producing *E. coli* from other E. coli strains (usually MUG positive) in gastrointestinal specimens, once the isolate has been identified as *E. coli.*\n\n### Microorganisms Tested\n\n- Fresh colonies on blood agar plate of possible *E. coli* that are indole-positive, oxidase-negative, Gram-negative rods, whether they are lactose positive or negative.\n- Do not use this test as part of an algorithm to rapidly identify *E. coli* in abdominal sources, since occasional isolates of both *Salmonella* and *Shigella* can be MUG positive.\n\n### Procedure for MUG test\n\n#### MUG tube method\n\n1. Prepare a dense milky suspension of the organism to be tested in a small tube containing 0.25 ml of saline. The suspension should be prepared from colonies growing on [MacConkey agar](\u002Fmacconkey-agar-mac-composition-preparation-uses-and-colony-characteristics\u002F).\n2. Add a MUG disk for detection of β-glucuronidase activity.\n3. Place a stopper in the tube and agitate vigorously for a few seconds.\n4. Incubate the tube at 35-37 °C for 2 hours.\n5. Observe fluorescence using long-wave UV light in a dark room.\n\n#### MUG disk method\n\n1. Place MUG disk in a sterile empty petri dish and wet with 1 drop of water. I*f excess water is used, test may be falsely negative.*\n2. Using a wooden stick or bacteriological loop, roll a colony of suspected *E.coli* from a blood agar plate onto the disk.\n3. Incubate at 35C for a minimum of 2 hours.\n4. Observe the disk using long-wave UV light in a darkened room.\n\n### Expected results of MUG Test\n\n1. Positive: Electric blue fluorescence\n2. Negative: Lack of fluorescence\n\n### Quality control of MUG Test\n\n1. Perform quality control on each new lot or shipment of disks or liquid reagent prior to use.\n2. Organisms\n\n*E. coli* ATCC 25922—blue fluorescence (positive) \\\n*Klebsiella pneumoniae* ATCC 13883 or ATCC 27736—no fluorescence (negative)\n\n### Limitations\n\n- Not all *E. coli* are MUG positive. A Negative MUG test does not mean that the organism is not *E. coli.*\n- Do not use media that contain dyes (e.g., [EMB agar](\u002Feosin-methylene-blue-emb-agar-composition-uses-colony-characteristics\u002F) or MacConkey agar) for the disk test. Dyes do not interfere with the tube test.\n- As some strains of *Salmonella, Shigella*, and *Yersinia* also MUG positive. Do not test lactose-negative organisms from abdominal sources or from blood with this method to avoid misidentification.\n- Do not perform MUG test for oxidase-positive organisms. Some fluorescing organisms, such as *Pseudomonas aeruginosa*, may resemble a positive MUG result.\n\n**References and further readings**\n\n1. Clinical Microbiology Procedures Handbook, Fourth Edition. (2016). American Society of Microbiology. \u003Chttps:\u002F\u002Fdoi.org\u002F10.1128\u002F9781555818814>",[],[],[],[48,54,61,66,70,74,79,84,88,92],{"slug":49,"name":38,"description":50,"image":51,"body":52,"postCount":53},"acharya-tankeshwar","Editor-in-chief","https:\u002F\u002Fassets.microbeonline.com\u002Fauthors\u002Ftankeshwar-acharya-author-microbeonline.jpg","***Tankeshwar Acharya, MSc (Medical Microbiology)***\n\n*Tankeshwar Acharya is an Assistant Professor in the Department of Microbiology at Patan Academy of Health Sciences (PAHS), Nepal, where he has been teaching and practicing clinical microbiology for over 14 years. He is the founder of Microbe Online, one of the leading free microbiology education resources on the web, covering bacteriology, mycology, parasitology, immunology, and clinical laboratory diagnostics written from direct experience in both the classroom and the diagnostic laboratory.*",432,{"slug":55,"name":56,"description":57,"image":58,"body":59,"postCount":60},"ashma-shrestha","Ashma Shrestha","SEO Copywriter and Science Communicator\nKathmandu, Nepal","https:\u002F\u002Fassets.microbeonline.com\u002Fauthors\u002Fashma-shrestha.png","Ashma Shrestha holds a Master of Science in Medical Microbiology from the Institute of Science and Technology (IOST), Tribhuvan University, Nepal, where she developed a strong foundation in virology, molecular biology, and diagnostic microbiology.\n\nShe now works as an SEO Copywriter at Resolution Digital, where she combines her scientific training with research-driven content strategy. She is certified in Google Analytics and Google Business Profile (GBP), and brings a data-informed approach to science communication writing content that is not only accurate but structured to reach and serve the students who need it most.\n\nAt microbeonline, Ashma contributes articles primarily in virology and molecular biology, areas she finds most compelling for their mechanistic depth and their growing clinical relevance. Her writing reflects the same standard the site is built on: factual rigor, clear explanation of the *why* behind microbiology concepts, and content that helps students move from memorization to genuine understanding.\n\nShe is passionate about making complex microbiological concepts accessible without sacrificing accuracy; a skill that sits at the intersection of her scientific training and her professional work in content and SEO.",81,{"slug":62,"name":63,"description":64,"image":37,"body":37,"postCount":65},"sushmita-baniya","Sushmita Baniya","Author \u002F Contributor",32,{"slug":67,"name":68,"description":64,"image":37,"body":37,"postCount":69},"samikshya-acharya","Samikshya Acharya",20,{"slug":71,"name":72,"description":64,"image":37,"body":37,"postCount":73},"alisha-tripathi","Alisha Tripathi",6,{"slug":75,"name":76,"description":77,"image":37,"body":37,"postCount":78},"aastha-shrestha","Aastha Shrestha"," Author \u002F Contributor",10,{"slug":80,"name":81,"description":82,"image":37,"body":37,"postCount":83},"guest-author","Guest Author","Guest Author \u002F Contributor",2,{"slug":85,"name":86,"description":64,"image":37,"body":37,"postCount":87},"srijana-khanal","Srijana Khanal",18,{"slug":89,"name":90,"description":82,"image":37,"body":37,"postCount":91},"dr-poonam-acharya","Dr. Poonam Acharya",1,{"slug":93,"name":94,"description":64,"image":37,"body":95,"postCount":96},"nisha-rijal","Nisha Rijal","**Nisha Rijal** is a microbiologist and quality assurance specialist. She served for nearly 12 years as a microbiologist at the National Public Health Laboratory (NPHL), Nepal's national reference laboratory, and continues to work as a consultant microbiologist in international public health organization. ",51]