[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"$fxLN3MUwXCdr5RPjwZYIDpOj8CHyjOmngWTgoKXPtZbg":3,"$f4la8Z2BOqw53qfr77qmxP-0hQWBlAnmSrl7r1DGEREU":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},"moraxella-catarrhalis","Moraxella catarrhalis: Properties, Lab Diagnosis",null,"Acharya Tankeshwar","2021-05-27","2025-12-29",false,"bacteriology","*Moraxella catarrhalis* is a small gram-negative diplococcus that resembles the cocci of the genus *Neisseria*. The genus *Moraxella* is one of the several in the family Neisseriaceae; other medically important genera are *Neisseria, Kingella*, and *Acinetobacter* spp).\n\n> Gram stain morphology of “diplococcus” separates Moraxella catarrhalis from other Moraxella organisms, which are “coccobacilli”\n\n*Moraxella catarrhalis* is the new name for *Branhamella catarrhalis. Moraxella* is named after a Swiss ophthalmologist, Victor Morax, who first described it. *Catarrhalis* is derived from catarrh, the Greek meaning “to flow down” (cata- implies down; -rrh implies flow), describing the profuse discharge from the eyes and nose typically associated with severe inflammation in colds.\n\n![ - Important properties ofMoraxella catarrhalis](https:\u002F\u002Fassets.microbeonline.com\u002Fblogs\u002FMoraxella-catarrhalis.jpg)Figure: Important properties of *Moraxella catarrhalis*\n\n## Source and Transmission\n\n*Moraxella catarrhalis* is found only in humans and is a commensal of the upper respiratory tract and genital tract. *M. catarrhalis* is not frequently isolated from the oropharynx of healthy adults but may be carried more frequently in children and older adults. It is *transmitted by respiratory aerosol* and can cause opportunistic respiratory tract infections.\n\n## Disease\n\n*M. catarrhalis* causes acute, localized infections such as otitis media, and sinusitis in children. In elderly patients with chronic obstructive pulmonary diseases, it may cause opportunistic lower respiratory tract infections such as bronchitis and bronchopneumonia.\n\nIt may cause life-threatening, systemic diseases including endocarditis and meningitis.\n\n## Laboratory Diagnosis\n\n**Gram staining**\n\n![Neisseria and Moraxella in Carboferm neisseria test](https:\u002F\u002Fassets.microbeonline.com\u002Fblogs\u002FCarboferm-neisseria-kit.jpg)Figure: *Neisseria* and *Moraxella* in Carboferm neisseria test\n\nGram-negative diplococci, 0.6-1 um oval with flattened adjacent sides. It can be found with pus cells (sometimes intracellular) in sputum smears.\n\n**Colony characteristics**\n\nOn blood agar and chocolate agar, *M. catarrhalis* produces distinctive grey-white, medium to large, raised or dome-shaped, dry, and brittle colonies which can be easily lifted off the medium with a wire loop.\n\nIn the clinical laboratory, isolates of *M. catarrhal is* must be distinguished from *Neisseria* spp.\n\n| Properties | *Moraxella catarrhalis* | *Neisseria gonorrhoeae* |\n| --- | --- | --- |\n| Gram Stain | Gram-negative diplococcus | Gram-negative diplococcus |\n| Growth of basic agar media at 35°C | Yes | No |\n| Enzyme Substrate | No reaction | Hydroxyprolylaminopeptidase (+ve) |\n| GLUT (δ-glutamyl-aminopeptidase) | \\-ve | \\-ve |\n| DNase | +ve | \\-ve |\n| Catalase test | +ve | +ve |\n| Superoxol (30% H 2 O 2 ) | Strain variable (1+ to 4+) | Strong 4+ “explosive” |\n| Butyrate test | +ve | \\-ve |\n| Polysaccharide from sucrose | \\-ve | \\-ve |\n| Acid from glucose | \\-ve | +ve |\n| Acid from maltose | \\-ve | +ve |\n| Acid from lactose | \\-ve | +ve |\n| Acid from sucrose | \\-ve | +ve |\n| Nitrate reduction | +ve | \\-ve |\n| Pigment | \\-ve | \\-ve |\n| Colistin susceptibility | Most strains susceptible | Resistant |\n\n## Treatment\n\nMost clinical isolates produce β-lactamase. Trimethoprim-sulfamethoxazole or amoxicillin-clavulanate can be used to treat these infections.\n\n**References and further reading**\n\n1. [Color Atlas and Textbook of Diagnostic Microbiology](https:\u002F\u002Famzn.to\u002F2vRkUvk), Koneman, 5th edition\n2. [Bailey & Scott’s Diagnostic Microbiology](https:\u002F\u002Famzn.to\u002F2WZxPHL), Forbes, 11th edition\n3. Gonorrhea Laboratory Information, Characteristics of *N. gonorrhoeae* and Related Species, *Moraxella catarrhalis*. Center for Disease Control (CDC)",[],[],[],[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.*",433,{"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]