[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"$fxLN3MUwXCdr5RPjwZYIDpOj8CHyjOmngWTgoKXPtZbg":3,"$fnHCbcHfPVWP-bobturnAGVOVreixunkhT4S2G5NczdI":32,"$fXiFL-UK4K9KEfCgriLRdARySWL20FIYeE8hg1c61SCI":232,"tag-blogs-enterobacteriaceae":335},[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",[33,40,47,52,57,61,65,69,73,78,82,86,91,95,100,105,109,113,118,123,127,131,135,140,144,149,153,157,162,167,171,176,180,184,188,192,196,200,204,208,212,216,220,224,228],{"slug":34,"name":35,"description":36,"image":37,"body":38,"postCount":39},"gram-negative-cocci","Gram-Negative Cocci and Coccobacilli","Neisseria, Moraxella, Haemophilus and related gram-negative coccal organisms","https:\u002F\u002Fassets.microbeonline.com\u002Ftags\u002Fgram-negative-cocci.png","# Gram Negative Cocci\n\nNeisseria gonorrhoeae, Neisseria meningitides, Moraxella catarrhalis, and other Neisseria spp. are clinically relevant gram-negative cocci.\n\nN. gonorrhoeae is the leading cause of sexually transmitted disease whereas N. meningitides is a leading cause of fatal bacterial meningitis.",10,{"slug":41,"name":42,"description":43,"image":44,"body":45,"postCount":46},"microscopy","Microscopy","Microscope types, components, and microscopy techniques",null,"These are list of blog posts related to microscopy. ",12,{"slug":48,"name":49,"description":50,"image":44,"body":44,"postCount":51},"gram-positive-cocci","Gram-Positive Cocci","Staphylococcus, Streptococcus, Enterococcus, Micrococcus — organisms, diseases, and identification tests",13,{"slug":53,"name":54,"description":55,"image":44,"body":44,"postCount":56},"gram-negative-rods","Gram-Negative Rods","Enterobacteriaceae family as well as Pseudomonas, Acinetobacter and related organisms",9,{"slug":58,"name":59,"description":60,"image":44,"body":44,"postCount":46},"gram-positive-rods","Gram-Positive Rods","Bacillus, Clostridium, Listeria, Corynebacterium, Actinomyces and related organisms",{"slug":62,"name":63,"description":64,"image":44,"body":44,"postCount":56},"mycobacteria","Mycobacteria","Mycobacterium tuberculosis, leprosy, atypical mycobacteria, and acid-fast organism diagnosis",{"slug":66,"name":67,"description":68,"image":44,"body":44,"postCount":39},"anaerobic-bacteriology","Anaerobic Bacteriology","Anaerobic organisms, anaerobic culture methods, and anaerobic infection diagnosis",{"slug":70,"name":71,"description":72,"image":44,"body":44,"postCount":46},"enterobacteriaceae","Enterobacteriaceae","Identification, differentiation, and clinical significance of Enterobacteriaceae family members",{"slug":74,"name":75,"description":76,"image":44,"body":44,"postCount":77},"spirochetes","Spirochetes","Treponema, Leptospira, Borrelia and spirochetal infections",6,{"slug":79,"name":80,"description":81,"image":44,"body":44,"postCount":51},"food-microbiology","Food Microbiology","Food-borne pathogens, food safety, spoilage, and preservation",{"slug":83,"name":84,"description":85,"image":44,"body":44,"postCount":46},"antimicrobial-susceptibility-testing","Antimicrobial Susceptibility Testing","Methods for testing antibiotic susceptibility in clinical microbiology",{"slug":87,"name":88,"description":89,"image":44,"body":44,"postCount":90},"antimicrobials-moa-amr","Antimicrobials (MOA & AMR)","Mechanisms, detection, and clinical significance of antimicrobial resistance",7,{"slug":92,"name":93,"description":94,"image":44,"body":44,"postCount":39},"sterilization-disinfection","Sterilization and Disinfection","Methods of sterilization and disinfection in healthcare and laboratory settings",{"slug":96,"name":97,"description":98,"image":44,"body":44,"postCount":99},"specimen-collection-transport","Specimen Collection and Transport","Collection, handling, and transport of clinical specimens for microbiological testing",18,{"slug":101,"name":102,"description":103,"image":44,"body":44,"postCount":104},"bacterial-structure-physiology","Bacterial Structure and Physiology","Bacterial cell structure, growth, physiology, and environmental factors affecting growth",20,{"slug":106,"name":107,"description":44,"image":44,"body":108,"postCount":77},"horizontal-gene-transfer","Horizontal Gene Transfer","Articles related to **Horizontal Gene Transfer**",{"slug":110,"name":111,"description":44,"image":44,"body":112,"postCount":77},"chromatography","Chromatography","Information about chromatographic techniques.",{"slug":114,"name":115,"description":116,"image":44,"body":117,"postCount":90},"electrophoresis","Electrophoresis","Information about Electrophoresis Techniques ","Detailed information  about Electrophoresis Techniques ",{"slug":119,"name":120,"description":121,"image":44,"body":122,"postCount":77},"pcr-techniques","PCR Techniques","Information about various types of Polymerase Chain Reaction Techniques ","More detailed information about various types of Polymerase Chain Reaction Techniques ",{"slug":124,"name":125,"description":126,"image":44,"body":44,"postCount":77},"bacteriophage","Bacteriophage","Description about Bacteriophage.",{"slug":128,"name":129,"description":130,"image":44,"body":44,"postCount":77},"malaria","Malaria","It is the collections of articles regarding malarial disease. ",{"slug":132,"name":133,"description":134,"image":44,"body":44,"postCount":77},"anaerobic-culture-techniques","Anaerobic Culture Techniques","Posts related with Anaerobic Culture Techniques.",{"slug":136,"name":137,"description":138,"image":44,"body":44,"postCount":139},"immunoassays","Immunoassays","You will get information about all the diagnostic tests that rely on the specific binding between an antigen and an antibody to detect or quantify a substance.",15,{"slug":141,"name":142,"description":143,"image":44,"body":44,"postCount":90},"biosafety-levels","Biosafety levels ","Articles related to Biosafety Levels",{"slug":145,"name":146,"description":147,"image":44,"body":44,"postCount":148},"environmental-factors","Environmental Factors ","In this case we are talking about growth requirements of microorganisms with deep dive in environmental factors that affect the growth. ",5,{"slug":150,"name":151,"description":152,"image":44,"body":44,"postCount":77},"pipette","Pipette","Posts related with Pipette. ",{"slug":154,"name":155,"description":156,"image":44,"body":44,"postCount":90},"bacteriology-mcqs","Bacteriology MCQs","This sections lists MCQs in Bacteriology.",{"slug":158,"name":159,"description":160,"image":44,"body":44,"postCount":161},"parasitology-mcqs","Parasitology MCQs","This section lists MCQs in Parasitology.",2,{"slug":163,"name":164,"description":165,"image":44,"body":44,"postCount":166},"virology-mcqs","Virology MCQs","This is the collections of Multiple Choice Questions in Virology.",4,{"slug":168,"name":169,"description":170,"image":44,"body":44,"postCount":148},"mcqs-in-microbiology","MCQs in Microbiology","This section lists the collections of Multiple Choice Questions in General Microbiology Topics. ",{"slug":172,"name":173,"description":174,"image":44,"body":44,"postCount":175},"immunology-mcqs","Immunology MCQs","In this section; we are posting collections of Multiple Choice Questions about Immunology. ",8,{"slug":177,"name":178,"description":179,"image":44,"body":44,"postCount":56},"microbial-curiosities","Microbial Curiosities","In this clusters, we are posting interesting and unique information about Microorganisms. ",{"slug":181,"name":182,"description":183,"image":44,"body":44,"postCount":90},"bacterial-culture-media","Bacterial Culture Media","Posts related to Bacterial Culture Media. ",{"slug":185,"name":186,"description":187,"image":44,"body":44,"postCount":77},"fungal-culture-media","Fungal Culture Media","Posts related to Fungal Culture Media.",{"slug":189,"name":190,"description":191,"image":44,"body":44,"postCount":148},"motility-test","Motility Test","This lists the procedure regarding various tests methods for bacterial motility.",{"slug":193,"name":194,"description":195,"image":44,"body":44,"postCount":39},"bacterial-enumeration","Bacterial enumeration","These posts are related to isolation and enumeration of bacteria. ",{"slug":197,"name":198,"description":199,"image":44,"body":44,"postCount":161},"gram-positive-coccobacillus","Gram-positive coccobacillus","List of Gram Positive Coccobacilli",{"slug":201,"name":202,"description":203,"image":44,"body":44,"postCount":166},"dimorphic-fungi","Dimorphic Fungi","This is about various dimorphic fungi. ",{"slug":205,"name":206,"description":207,"image":44,"body":44,"postCount":90},"bacterial-classification","Bacterial Classification","These posts are related with various approaches used for the classification of Bacteria. ",{"slug":209,"name":210,"description":211,"image":44,"body":44,"postCount":166},"immunofluorescence","Immunofluorescence ","Various Tests related to Immunofluorescence ",{"slug":213,"name":214,"description":215,"image":44,"body":44,"postCount":77},"antibody-mediated-immunity","Antibody-mediated Immunity","This clusters links the articles that are sharing insights about Antibody-mediated immunity. ",{"slug":217,"name":218,"description":219,"image":44,"body":44,"postCount":77},"hypersensitivity","Hypersensitivity","Articles related to Hypersensitivity.",{"slug":221,"name":222,"description":44,"image":44,"body":44,"postCount":223},"haemophilus","Haemophilus",3,{"slug":225,"name":226,"description":227,"image":44,"body":44,"postCount":223},"sexually-transmitted-infections-stis","Sexually transmitted infections (STIs)","This is the clusters of infections that are transmitted sexually. ",{"slug":229,"name":230,"description":231,"image":44,"body":44,"postCount":166},"adaptive-immunity","Adaptive Immunity","Blog posts related to B Cell Immunity and T Cell Immunity.",[233,240,247,253,260,267,274,281,288,295,302,309,316,322,328],{"slug":234,"name":235,"description":236,"image":237,"body":238,"postCount":239},"bacteriology","Bacteriology","Identify, classify, and understand clinically important bacteria from Gram stain to pathogenesis with exam-ready articles for medical and lab science students.","https:\u002F\u002Fassets.microbeonline.com\u002Fcategories\u002Fbacteriology.png","A Gram stain result comes back from the lab: Gram-positive cocci in clusters. Before you order the antibiotic, you need to know whether that is *Staphylococcus aureus* or a coagulase-negative contaminant. That single question determines treatment, prognosis, and whether the patient goes home or to the ICU.\n\nBacteriology is the study of bacteria: their structure, growth, identification, and the diseases they cause. It is the backbone of clinical microbiology, and the category with the most direct impact on patient care.\n\nThis section covers:\n\n- **Organism profiles**: morphology, staining, culture characteristics, virulence factors, and clinical disease for all major pathogens (Staphylococcus, Streptococcus, Enterobacteriaceae, Pseudomonas, Mycobacterium, anaerobes, and more)\n- **Laboratory identification**: the step-by-step diagnostic logic used to move from a specimen to a confirmed species\n- **Differentiation articles**: side-by-side comparisons of organisms that students routinely confuse (e.g., *S. aureus* vs. *S. epidermidis*, *E. coli* vs. *Klebsiella*)\n- **Antimicrobial susceptibility testing**: the methods, interpretation, and clinical relevance of MIC, disk diffusion, and resistance mechanisms\n\nWhether you are preparing for MBBS exams, a laboratory science board, or clinical posting, every article is written to answer three questions: What is this organism? Why does it matter clinically? How will you remember it when it appears on an exam or a culture report?",137,{"slug":241,"name":242,"description":243,"image":244,"body":245,"postCount":246},"biochemical-tests","Biochemical Tests","Learn how catalase, oxidase, urease, and 50+ other biochemical tests work — with expected results, clinical significance, and exam mnemonics.","https:\u002F\u002Fassets.microbeonline.com\u002Fcategories\u002Fbiochemical-tests.png","The organism grew overnight on blood agar. It is Gram-positive and catalase-positive. Now what? The next step is a panel of biochemical tests — each one asking a specific question about the organism's metabolism and together they narrow a field of thousands of possible bacteria down to a single species.\n\nBiochemical tests are the chemical reactions used to identify bacteria based on their enzymatic activity and metabolic products. They are the bridge between \"something grew\" and \"we know what it is.\"\n\nThis section covers every major test in clinical and teaching laboratory use:\n\n- **Individual test articles**: the principle behind each test, how it is performed, how to read the result, and what a positive or negative finding means for identification\n- **Expected results tables**: organism-by-organism result summaries, formatted for quick exam review\n- **Where students get confused**: common pitfalls such as false positives, interfering substances, and tests that are visually similar but detect different enzymes\n\nEach article follows the same logic a clinical microbiologist uses at the bench: What does this test detect? Why does this organism give this result? How do you remember which organisms are positive?\n\nIf you are working through a biochemical identification flowchart for the first time, start with the catalase test and follow the logic forward.",58,{"slug":248,"name":249,"description":250,"image":251,"body":252,"postCount":166},"cell-biology","Cell Biology","Posts related to cell biology","https:\u002F\u002Fassets.microbeonline.com\u002Fcategories\u002Fcell-biology.png","# Cell Biology\n\nThis page contains all posts in the Cell Biology category.",{"slug":254,"name":255,"description":256,"image":257,"body":258,"postCount":259},"culture-media","Culture Media","Understand the composition, purpose, and clinical use of 40+ bacteriological culture media from blood agar to TCBS, with organism-specific selection logic.","https:\u002F\u002Fassets.microbeonline.com\u002Fcategories\u002Fculture-media.png","A specimen arrives in the laboratory. Before any identification can happen, the organisms in that specimen must be grown and the medium you choose determines what grows and what does not. Select MacConkey agar and you will see lactose fermenters change color; use Thayer-Martin and you selectively support *Neisseria gonorrhoeae* while suppressing everything else.\n\nCulture media are the nutrient environments prepared in the laboratory to grow, isolate, and differentiate microorganisms. Choosing the right medium is not a procedural detail, it is a diagnostic decision.\n\nThis section covers all major bacteriological and mycological culture media, organized around three questions:\n\n- **Composition**: what is in the medium and why each ingredient is there\n- **Purpose**: whether the medium is general-purpose, selective, differential, enrichment, or transport\n- **Clinical use**: which specimens it is used for, which organisms it supports, and how to interpret growth or color changes\n\nArticles range from everyday laboratory workhorses like blood agar, chocolate agar, and MacConkey agar, to specialized media like Löwenstein-Jensen for mycobacteria, TCBS for *Vibrio*, and Sabouraud Dextrose Agar for fungi.\n\nIf you have ever wondered why the microbiology laboratory chooses three different plates for a single stool specimen, this section will make that logic clear.",49,{"slug":261,"name":262,"description":263,"image":264,"body":265,"postCount":266},"difference-between","Difference Between","Side-by-side comparisons of commonly confused microbiology concepts; exotoxins vs. endotoxins, bacteriostatic vs. bactericidal, and more, with exam tables.","https:\u002F\u002Fassets.microbeonline.com\u002Fcategories\u002Fdifference_between.png","Some of the most common exam mistakes in microbiology do not come from unfamiliar topics; they come from concepts that look similar but are not. Exotoxin versus endotoxin. Gram-positive versus Gram-negative cell walls. Primary versus secondary immune response. Bacteriostatic versus bactericidal.\n\nThis section exists specifically for those confusions. Each article takes two or more closely related concepts and breaks down the differences systematically: definition, mechanism, examples, clinical significance, and a structured comparison table designed for revision.\n\nThe articles here are built around the questions students actually get wrong on MCQ papers, not just the ones that seem important in theory. If a pair of concepts appears repeatedly in exam distractors or in clinical viva questions, it belongs here.\n\nUse this section for targeted revision of the distinctions that cost marks.",16,{"slug":268,"name":269,"description":270,"image":271,"body":272,"postCount":273},"general-microbiology","General Microbiology","Foundational microbiology for medical and lab science students; microbial structure, classification, sterilisation, infection control, and host-pathogen biology.","https:\u002F\u002Fassets.microbeonline.com\u002Fcategories\u002Fgeneral-microbiology.png","Before you can identify a pathogen, understand an infection, or interpret a laboratory result, you need the conceptual foundations of microbiology. What makes a bacterium different from a virus? Why does sterilisation fail if temperature is correct but time is inadequate? How does a pathogen move from a reservoir to a host and establish infection?\n\nGeneral Microbiology covers the principles that underpin every other category on this site:\n\n- **Microbial classification and structure**: the taxonomy of bacteria, viruses, fungi, and parasites; cell wall architecture; spore formation; and the features that make each group clinically distinct\n- **Sterilisation and disinfection**: the methods, mechanisms, and monitoring of physical and chemical decontamination, including autoclave validation, the role of endospores, and the hierarchy of microbial killing\n- **Infection and host-pathogen interaction**: colonisation versus infection, virulence determinants, routes of transmission, and the basics of host immunity\n- **Laboratory safety and infection control**: biosafety levels, standard precautions, and aseptic technique principles\n\nThis is the section to start with if you are new to microbiology, and the section to return to when clinical categories raise questions that need a conceptual anchor.",100,{"slug":275,"name":276,"description":277,"image":278,"body":279,"postCount":280},"immunology","Immunology","Learn innate and adaptive immunity, antibody structure, hypersensitivity, complement, and immunodiagnostic tests explained with clinical application and exam focus.","https:\u002F\u002Fassets.microbeonline.com\u002Fcategories\u002Fimmunology.png","A child receives a vaccine and, years later, their immune system recognizes the same pathogen and destroys it before a single symptom appears. A patient receives a mismatched blood transfusion and goes into shock within minutes. Both events are driven by the immune system; one a triumph of immunological memory, the other a catastrophic hypersensitivity reaction.\n\nImmunology is the study of how the body defends itself against infection, how that defense can go wrong, and how we harness immune mechanisms for diagnosis and treatment.\n\nThis section covers:\n\n- **Innate and adaptive immunity**: physical barriers, phagocytosis, natural killer cells, T and B lymphocytes, and the logic of clonal selection\n- **Antibody structure and function**: immunoglobulin classes, antigen-antibody interactions, and the significance of IgM versus IgG in acute versus past infection\n- **Complement system**: pathways, effector functions, and clinical consequences of deficiency\n- **Hypersensitivity reactions**: Type I through Type IV, with clinical examples including anaphylaxis, serum sickness, contact dermatitis, and transplant rejection\n- **Immunodiagnostic tests**: ELISA, agglutination, precipitation, immunofluorescence, and the principles behind serological interpretation\n\nImmunology confuses students because the same terms (antigen, antibody, complement) appear in multiple contexts with subtly different meanings. Every article in this section is written to make those connections explicit rather than leaving them as an exercise for the reader.",51,{"slug":282,"name":283,"description":284,"image":285,"body":286,"postCount":287},"lab-equipment","Lab Equipment & Techniques","Master lab instruments and techniques used in microbiology and molecular diagnostics-microscopy, electrophoresis, PCR, blotting, chromatography, and more.","https:\u002F\u002Fassets.microbeonline.com\u002Fcategories\u002Flab-equipment.png","A patient with suspected tuberculosis has a negative sputum smear. The clinician orders a PCR-based test. The result comes back positive but the lab technician notices the band on the gel appeared in the negative control lane too. Was it contamination during PCR setup? A pipetting error? A mislabeled tube? Before anyone can answer, they need to understand not just that these techniques exist, but how each step works and where each one can fail.\n\nIn diagnostic microbiology, the technique is part of the diagnosis. A result is only as reliable as the method that produced it -- and the person who ran it.\n\nThis section covers the full range of laboratory instruments and analytical techniques used in clinical microbiology, molecular diagnostics, and biomedical laboratory science:\n\n**Instruments and equipment:**\n\n- **Sterilization equipment**: autoclave, hot air oven, UV chambers, and filtration apparatus; operating principles, cycle validation, and failure modes\n- **Microscopy**: bright-field, dark-field, phase-contrast, and fluorescence microscopy; lens systems; oil immersion technique; care and maintenance\n- **Measurement and dispensing**: micropipettes, graduated and serological pipettes, balances, and volumetric glassware; calibration and common errors\n- **Centrifugation**: types of centrifuges, rotor systems, RPM versus RCF conversion, and safe operation\n- **Incubators, water baths, and temperature-controlled equipment**: calibration, temperature uniformity, and CO2 incubator monitoring\n\n**Separation and analytical techniques:**\n\n- **Electrophoresis**: agarose gel and polyacrylamide gel electrophoresis (PAGE); how charge, size, and matrix interact to separate molecules; DNA, RNA, and protein applications; band pattern interpretation\n- **Blotting methods**: Southern blotting (DNA), Northern blotting (RNA), and Western blotting (protein); how transfer and hybridization work; clinical and research applications\n- **Chromatography**: separation based on differential affinity; thin-layer, column, gas, and high-performance liquid chromatography (HPLC); applications in clinical chemistry and molecular biology\n- **Spectrophotometry and colorimetry**: absorbance-based quantification; Beer-Lambert law; OD600 for bacterial growth curves; enzyme and diagnostic assay applications\n\n**Molecular techniques:**\n\n- **PCR and its variants**: conventional PCR, real-time (qPCR), reverse transcription PCR (RT-PCR), multiplex PCR, nested PCR, and digital PCR; principles, setup, controls, and interpretation\n- **Nucleic acid extraction and quantification**: methods for isolating DNA and RNA from clinical specimens; purity ratios; storage considerations\n- **Sequencing and genotyping**: Sanger sequencing, next-generation sequencing (NGS) concepts, and their role in outbreak investigation and resistance gene identification\n\nEach article is built around the teaching framework that makes techniques genuinely learnable: What does this method detect or separate, and how does it work? Why does each step matter and what happens to the result if a step goes wrong? How do you remember the logic well enough to troubleshoot a real problem at the bench?\n\nTheory-heavy technique articles (like electrophoresis or blotting principles) open with a clinical scenario that shows why the technique exists. Procedural articles (like PCR setup or micropipette calibration) open with the step students most commonly get wrong because that is where understanding actually breaks down.",84,{"slug":289,"name":290,"description":291,"image":292,"body":293,"postCount":294},"mcqs","MCQs","Practice microbiology MCQs with detailed answer explanations (covering bacteriology, virology, immunology, and lab diagnosis) for MBBS and board exam preparation.","https:\u002F\u002Fassets.microbeonline.com\u002Fcategories\u002Fmcqs.png","Reading an article tells you the fact. Answering a question tells you whether you understood it  and more importantly, whether you can apply it when a distractor option is deliberately designed to look correct.\n\nThis section provides multiple-choice questions across all major microbiology topics, with a format that goes beyond a simple answer key. Each question set includes:\n\n- **Correct answer with explanation**: not just *what* is right, but *why* each distractor is wrong\n- **The underlying concept tested**: so you know which gap in your knowledge the question is probing\n- **Exam-style framing**: questions written to reflect the clinical scenario and reasoning patterns used in MBBS, USMLE Step 1, and equivalent licensing examinations\n\nMicrobiology MCQs tend to test a small set of high-yield facts repeatedly: key virulence factors, distinguishing test results, antibiotic mechanisms, and serological interpretation. The questions here are built around those patterns, not around obscure facts that rarely appear in clinical or exam contexts.\n\nUse this section alongside the main content categories: read the article first, then test yourself with the MCQs to confirm retention.",28,{"slug":296,"name":297,"description":298,"image":299,"body":300,"postCount":301},"molecular-biology","Molecular Biology","Understand DNA replication, transcription, translation, PCR, and molecular diagnostic techniques with clinical microbiology applications and exam-focused explanations.","https:\u002F\u002Fassets.microbeonline.com\u002Fcategories\u002Fmolecular-biology.png","A patient presents with symptoms consistent with tuberculosis, but the sputum smear is negative. A molecular test detects *Mycobacterium tuberculosis* DNA directly from the specimen in hours  and simultaneously reports whether the strain is rifampicin-resistant. That result changes everything: the diagnosis is confirmed, and the treatment is adjusted before a single culture result is available.\n\nMolecular biology has moved from the research laboratory to the clinical microbiology workflow, and understanding its principles is no longer optional for students in medicine or laboratory science.\n\nThis section covers molecular biology from foundational principles through clinical diagnostic applications:\n\n- **Core molecular processes**: DNA structure, replication, transcription, and translation; mutations and their consequences; plasmids and mobile genetic elements\n- **PCR and its variants**: conventional PCR, real-time (qPCR), reverse transcription PCR (RT-PCR), and multiplex PCR, with emphasis on how each is used in diagnostic microbiology\n- **Molecular diagnostic methods**: nucleic acid amplification tests (NAATs), sequencing, hybridization techniques, and point-of-care molecular platforms\n- **Antimicrobial resistance at the molecular level**: resistance genes, horizontal gene transfer, and how genotypic resistance testing differs from phenotypic testing\n- **Recombinant DNA and cloning**: vectors, restriction enzymes, gene libraries, and expression systems relevant to vaccine and reagent production\n\nEach article is written to connect the molecular mechanism to a clinical or laboratory outcome. Knowing how PCR works is useful; knowing why a false-positive PCR result can occur and how to interpret it is essential.",22,{"slug":303,"name":304,"description":305,"image":306,"body":307,"postCount":308},"mycology","Mycology","Study clinically important fungi (Candida, Aspergillus, Cryptococcus, dermatophytes, and dimorphic fungi) with identification methods, lab diagnosis, and exam focus.","https:\u002F\u002Fassets.microbeonline.com\u002Fcategories\u002Fmycology.png","A patient on prolonged broad-spectrum antibiotics develops oral white plaques and a burning sensation. The Gram stain shows Gram-positive budding yeast with pseudohyphae. *Candida albicans*; an organism that normally lives harmlessly on mucosal surfaces  has become a pathogen because the microbial competition was eliminated.\n\nFungi are eukaryotic organisms that cause infections ranging from superficial skin disease to life-threatening systemic illness. They are increasingly important in clinical practice because the patients most vulnerable to fungal infections (those on immunosuppressants, chemotherapy, or prolonged antibiotics, and those with HIV) are a growing population.\n\nThis section covers:\n\n- **Fungal structure and classification**: yeasts, moulds, and dimorphic fungi; cell wall composition; hyphal morphology; and the clinical significance of these structural differences\n- **Organism profiles**: *Candida*, *Aspergillus*, *Cryptococcus*, *Histoplasma*, *Coccidioides*, *Mucor*, dermatophytes, and other clinically relevant genera\n- **Laboratory identification**: direct microscopy (KOH preparation, India ink, Gram stain), culture on Sabouraud Dextrose Agar, germ tube test, biochemical identification, and antifungal susceptibility testing\n- **Pathogenesis and clinical disease**: the conditions that predispose to fungal infection, the mechanisms by which fungi cause tissue damage, and the major clinical syndromes\n\nMycology is often treated as a secondary topic in microbiology curricula, but its clinical importance in immunocompromised patients makes it exam-relevant and patient-care-relevant in equal measure.",26,{"slug":310,"name":311,"description":312,"image":313,"body":314,"postCount":315},"parasitology","Parasitology","Learn the life cycles, morphology, lab diagnosis, and clinical significance of parasites; protozoa, helminths, and ectoparasites for medical and lab science exams.","https:\u002F\u002Fassets.microbeonline.com\u002Fcategories\u002Fparasitology.png","Malaria kills a child every two minutes. Globally, over a billion people carry intestinal helminths. *Toxoplasma gondii* infects approximately one-third of the world's population, mostly silently. Parasitic infections are not rare tropical curiosities; they are among the most prevalent infectious diseases on earth, with direct relevance to clinical practice in every part of the world.\n\nParasitology is the study of eukaryotic organisms (protozoa, helminths, and arthropods) that live in or on a host and cause harm. It requires a different kind of thinking from bacteriology: life cycles, intermediate hosts, vectors, and the tissue stages that determine symptoms all matter in ways that have no equivalent in bacterial infection.\n\nThis section covers:\n\n- **Protozoa**: *Plasmodium* (malaria), *Leishmania*, *Trypanosoma*, *Entamoeba*, *Giardia*, *Cryptosporidium*, *Toxoplasma*, and others; life cycle, transmission, clinical disease, and laboratory diagnosis\n- **Helminths**: roundworms, tapeworms, and flukes; species that cause intestinal, tissue, and blood infections; morphology and diagnostic stage identification\n- **Ectoparasites**: lice, scabies mites, and their role in disease transmission\n- **Laboratory diagnosis**: stool examination (wet mount, concentration techniques, staining), blood film microscopy for malaria and microfilariae, serological tests, and antigen detection\n\nFor each organism, the article answers the same set of questions: What is the infective stage? How does the host acquire it? What does the patient present with? How is it identified in the laboratory?",27,{"slug":317,"name":318,"description":319,"image":320,"body":321,"postCount":148},"science-communication","Science Communication","Posts related to science communication","https:\u002F\u002Fassets.microbeonline.com\u002Fcategories\u002Fscience-communication.png","# Science Communication\n\nThis page contains all posts in the Science Communication category.",{"slug":323,"name":324,"description":325,"image":326,"body":327,"postCount":266},"staining-techniques","Staining Techniques","Learn the principle, procedure, and interpretation of Gram stain, Ziehl-Neelsen, Giemsa, and other clinical microbiology staining techniques, with common errors explained","https:\u002F\u002Fassets.microbeonline.com\u002Fcategories\u002Fstaining-techniques.png","A smear from a sputum specimen is fixed to a glass slide, flooded with carbol fuchsin, heated, decolorized with acid-alcohol, and counterstained with methylene blue. If acid-fast bacilli are present, they retain the red stain against a blue background and a patient with suspected tuberculosis is now one step closer to a confirmed diagnosis.\n\nStaining techniques transform invisible microorganisms into visible, interpretable findings. They are among the oldest tools in diagnostic microbiology and remain essential in every clinical laboratory, including in resource-limited settings where molecular testing is unavailable.\n\nThis section covers all major staining methods in clinical and research microbiology:\n\n- **Gram stain**: principle of differential staining based on cell wall composition, step-by-step procedure, results interpretation, common errors and their causes\n- **Ziehl-Neelsen (acid-fast) stain**: for *Mycobacterium* and *Nocardia*; hot and cold methods; modified protocols for *Cryptosporidium*\n- **Special stains**: Albert's stain for diphtheria, India ink for *Cryptococcus*, lactophenol cotton blue for fungi, Giemsa for blood parasites and *Chlamydia*, Wayson's stain, and others\n- **Fluorescent staining**: auramine-rhodamine as a screening stain for acid-fast bacilli; acridine orange; and calcofluor white for fungi\n\nEach article covers the chemical principle behind the stain, the step-by-step procedure, how to interpret the result, what a false-positive or false-negative looks like, and how this stain fits into the diagnostic algorithm for the relevant organisms.",{"slug":329,"name":330,"description":331,"image":332,"body":333,"postCount":334},"virology","Virology","Study clinically important viruses; structure, replication, pathogenesis, lab diagnosis, and vaccines with exam-focused articles for medical and lab science students.","https:\u002F\u002Fassets.microbeonline.com\u002Fcategories\u002Fvirology.png","In 2020, a novel coronavirus spread across the world, and within weeks, clinical microbiologists had characterized its genome, developed PCR-based diagnostic tests, and begun evaluating serological assays for population-level surveillance. That speed was possible because the foundational principles of virology (viral structure, replication, tropism, and immune evasion) were already understood.\n\nVirology is the study of viruses: obligate intracellular parasites that require a host cell to replicate, cause disease through mechanisms distinct from bacteria or fungi, and pose unique diagnostic challenges because they cannot be grown on standard bacteriological media.\n\nThis section covers:\n\n- **Viral structure and classification**: capsid morphology, envelope composition, genome type (DNA vs. RNA, single- vs. double-stranded, segmented vs. non-segmented), and the Baltimore classification system\n- **Viral replication**: attachment, entry, genome replication, assembly, and release; how antiviral drugs target specific steps in this cycle\n- **Organism profiles**: all major clinically important virus families, including Herpesviridae, Hepatitis viruses, HIV, Influenza, Dengue, Measles, Rabies, HPV, Rotavirus, and others\n- **Pathogenesis and immune evasion**: how viruses cause cell damage, establish latency, and evade host immune responses\n- **Laboratory diagnosis**: cell culture, PCR-based detection, antigen testing, and serology; how to interpret IgM versus IgG results; the role of viral load testing in monitoring\n\nA recurring theme in clinical virology is the interpretation of serological results, understanding that IgM indicates recent infection and IgG indicates past exposure or vaccination, and knowing when those rules have exceptions, is as important as memorizing which virus causes which disease.",31,{"items":336,"total":46,"page":506,"limit":139,"totalPages":506},[337,363,371,380,398,406,437,444,451,458,464,471],{"slug":338,"title":339,"description":340,"seoTitle":44,"seoDescription":44,"author":341,"createdDate":342,"lastUpdatedDate":343,"draft":344,"category":241,"faq":345,"tags":361,"image":362},"mixed-acid-fermentation","Mixed Acid Fermentation: The Pathway That Makes E. coli Methyl Red-Positive","Mixed acid fermentation splits glucose into a mixture of strong acids, lactate, acetate, formate, succinate, plus ethanol, in variable proportions. That flood of acid drops the pH below 4.4, which is exactly what the methyl red test detects. Here is the pathway, the enzymes, why \"mixed\" is the whole point, and how it differs from the 2,3-butanediol route that VP detects.","Ashma Shrestha","2023-08-21","2026-07-15",false,[346,349,352,355,358],{"question":347,"answer":348},"Why is E. coli methyl red-positive?","Because E. coli carries out mixed acid fermentation. When it ferments glucose anaerobically, it produces a mixture of strong acids, lactic, acetic, formic, and succinic, along with ethanol, all at once. These acids accumulate and drive the pH of the medium below 4.4. The methyl red test detects exactly this: methyl red turns red at pH 4.4 or below, so a mixed-acid fermenter like E. coli gives a positive (red) methyl red result. The test is essentially a readout of whether the organism ran mixed acid fermentation.",{"question":350,"answer":351},"What makes mixed acid fermentation different from other fermentations?","It produces several end products simultaneously in variable proportions, rather than one product in a fixed amount. Homolactic fermentation makes only lactate; alcoholic fermentation makes ethanol and CO2. Mixed acid fermentation makes a mixture, lactic, acetic, formic, and succinic acids plus ethanol and gas, and the exact proportions vary with the organism and conditions. This variable mixture is what the name refers to and is why it drives the pH low enough to be detected by the methyl red test.",{"question":353,"answer":354},"What is the difference between mixed acid fermentation and the 2,3-butanediol pathway?","They are the two roads enteric bacteria take from pyruvate. Mixed acid fermentation produces strong acids that lower the pH and is detected by the methyl red test; E. coli, Salmonella, Shigella, and Proteus take this road. The 2,3-butanediol pathway produces mostly neutral products (acetoin and 2,3-butanediol), spares the pH, and is detected by the Voges-Proskauer test; Klebsiella, Enterobacter, and Serratia take this road. The two are largely mutually exclusive, which is why the methyl red and VP tests usually give opposite results.",{"question":356,"answer":357},"Why do some mixed acid fermenters produce gas and others do not?","Gas production depends on a specific enzyme, formate hydrogen-lyase, which splits the formic acid made during mixed acid fermentation into carbon dioxide and hydrogen. A mixed-acid fermenter that has this enzyme produces gas, seen as a bubble in a Durham tube. One that lacks or has limited formate hydrogen-lyase, such as Shigella or Salmonella Typhi, still ferments glucose to acid but produces no gas, making it anaerogenic. So acid production and gas production are separate features.",{"question":359,"answer":360},"Why is mixed acid fermentation important in biotechnology?","Because its end products, ethanol, succinate, lactate, and acetate, are commercially valuable, and the pathway's flexibility makes it tunable. Since E. coli can be directed toward one product or another, strains have been metabolically engineered to over-produce specific end products, for example ethanol as a biofuel or succinate as a chemical feedstock. The same feature that makes the pathway produce a variable mixture makes it a useful target for metabolic engineering, with redox balance being the main constraint.",[70],"https:\u002F\u002Fassets.microbeonline.com\u002Fblogs\u002FMixed-Acid-Fermentation-in-E.-coli.jpg",{"slug":364,"title":365,"description":365,"seoTitle":44,"seoDescription":44,"author":341,"createdDate":366,"lastUpdatedDate":367,"draft":344,"category":234,"faq":368,"tags":369,"image":370},"klebsiella-oxytoca-properties-and-pathogenesis","Klebsiella oxytoca: Properties and Pathogenesis","2022-07-12","2026-07-05",[],[70],"https:\u002F\u002Fassets.microbeonline.com\u002Fblogs\u002FKlebsiella-oxytoca-1.png",{"slug":372,"title":373,"description":373,"seoTitle":44,"seoDescription":44,"author":374,"createdDate":375,"lastUpdatedDate":376,"draft":344,"category":234,"faq":377,"tags":378,"image":379},"yersinia-pestis-properties-disease-diagnosis","Yersinia pestis: Properties, Disease, Lab Diagnosis","Acharya Tankeshwar","2020-04-24","2026-07-19",[],[70],"https:\u002F\u002Fassets.microbeonline.com\u002Fblogs\u002FYersinia-pestis.jpg",{"slug":381,"title":382,"description":383,"seoTitle":44,"seoDescription":44,"author":374,"createdDate":384,"lastUpdatedDate":385,"draft":344,"category":241,"faq":386,"tags":396,"image":397},"kliglers-iron-agar-kia-principle-procedure-and-results","Kligler’s Iron Agar (KIA): Principle, Procedure, Results","A faint black line at the slant-butt junction is easy to overlook, and it's exactly the reaction that can point toward Salmonella Typhi. Full KIA principle, tube-reading rules, and the KIA\u002FTSI distinction explained.","2019-04-30","2026-07-12",[387,390,393],{"question":388,"answer":389},"Why does KIA give an alkaline slant\u002Facid butt (K\u002FA) result for glucose-only fermenters?","KIA contains glucose (0.1%) and lactose (1.0%) at a 10:1 concentration ratio. A glucose-only fermenter initially produces acid throughout the tube, turning both slant and butt yellow. However, glucose is quickly exhausted. The organism then shifts to aerobic oxidative metabolism on the slant surface, oxidatively deaminating peptone to produce alkaline amine compounds — the slant reverts to red\u002Falkaline. The anaerobic butt retains the acid from initial glucose fermentation. Result: K\u002FA. Organisms that ferment lactose (10x more concentrated) maintain sustained acid production throughout the tube, giving A\u002FA.",{"question":391,"answer":392},"What is the critical difference between Vibrio cholerae results on KIA vs TSI?","Vibrio cholerae ferments glucose and sucrose but NOT lactose. On KIA (which contains only glucose and lactose): the organism ferments glucose only, giving a K\u002FA result — identical to Salmonella or Shigella. On TSI (which contains glucose, lactose, AND sucrose): V. cholerae also ferments sucrose, giving an A\u002FA result. This distinction is diagnostically critical — in a cholera outbreak setting, a K\u002FA result on KIA alone could lead to V. cholerae being worked up as Salmonella. Always use TSI rather than KIA alone when V. cholerae is clinically suspected, and confirm with oxidase test, string test, and serology.",{"question":394,"answer":395},"If a KIA tube shows heavy black precipitate throughout, how should the butt colour be interpreted?","A heavily H₂S-positive KIA tube where black iron sulphide precipitate obscures the butt colour should always be interpreted as acid (A) in the butt — regardless of whether yellow colour is visible. H₂S is only produced in an acidic environment, so the presence of H₂S itself confirms the butt is acid. Never report an H₂S-positive tube as K\u002FK. The blackening in the butt indicates glucose fermentation (acid) plus H₂S production, making the full reading: K\u002FA + H₂S positive — consistent with Salmonella (non-Typhi) or Citrobacter.",[70],"https:\u002F\u002Fassets.microbeonline.com\u002Fblogs\u002FStreak-and-stab-slant-and-butt.jpg",{"slug":399,"title":400,"description":400,"seoTitle":44,"seoDescription":44,"author":374,"createdDate":401,"lastUpdatedDate":402,"draft":344,"category":234,"faq":403,"tags":404,"image":405},"klebsiella-pneumoniae-properties-virulence-diseases-diagnosis","Klebsiella pneumoniae: Properties, Diseases, Lab Diagnosis","2019-03-26","2026-07-18",[],[70],"https:\u002F\u002Fassets.microbeonline.com\u002Fblogs\u002FKlebsiella-pneumoniae.jpg",{"slug":407,"title":408,"description":409,"seoTitle":410,"seoDescription":411,"author":374,"createdDate":412,"lastUpdatedDate":402,"draft":344,"category":241,"faq":413,"tags":435,"image":436},"api-20e-test-system-introduction-procedure-results-interpretations","API 20E Test: Procedure, Reading the 21 Reactions, and the 7-Digit Profile Code","How to set up, incubate, and read the API 20E strip: which wells need oil, which need reagents, how to run the 21st test (oxidase), and how to build the 7-digit profile number for identification.","API 20E: Inoculation, Reading, Profile Number, and Identification","Prepare and inoculate an API 20E strip, add reagents, read biochemical reactions, calculate the profile number, and interpret organism identification.","2015-05-06",[414,417,420,423,426,429,432],{"question":415,"answer":416},"How many tests are in the API 20E, 20 or 21?","The strip has 20 wells, but a complete identification uses 21 reactions. The oxidase test is performed separately, off the strip, and fills the last position in the profile code.",{"question":418,"answer":419},"Which API 20E wells need a mineral oil overlay?","Five: ADH, LDC, ODC, URE, and H₂S. The oil creates the anaerobic conditions these reactions need. Without it, they read falsely.",{"question":421,"answer":422},"Which wells need reagents added after incubation?","Three: TDA (ferric chloride), IND (Kovács' reagent), and VP (KOH followed by α-naphthol). Add these only after reading every self-developing well.",{"question":424,"answer":425},"Why does the VP well take longer to read?","The pink-red color from acetoin detection can take up to 10 minutes to develop. Do not call VP negative before then. TDA and IND, by contrast, are read almost immediately.",{"question":427,"answer":428},"How is the 7-digit profile number generated?","The 21 reactions are grouped into seven triplets. Within each triplet the wells score 1, 2, and 4 from top to bottom; you add up only the positives, giving a digit from 0 to 7. The seven digits form the profile, which you look up in apiweb or the API catalog.",{"question":430,"answer":431},"What do I do if the profile gives a doubtful or low-confidence identification?","apiweb reports a %ID and a T-value; a low or non-discriminating result means you need supplementary tests (such as oxidase, nitrate reduction, or motility) or a repeat run, rather than accepting the closest match.",{"question":433,"answer":434},"Can API 20E identify organisms other than Enterobacteriaceae?","It is designed for Enterobacteriaceae and other non-fastidious Gram-negative rods. It is not suitable for fastidious organisms or non-fermenters outside its database scope, which need different panels.",[70],"https:\u002F\u002Fassets.microbeonline.com\u002Fblogs\u002FAPI-20-E.jpg",{"slug":438,"title":439,"description":439,"seoTitle":44,"seoDescription":44,"author":374,"createdDate":440,"lastUpdatedDate":402,"draft":344,"category":234,"faq":441,"tags":442,"image":443},"shigella-disease-properties-pathogenesis-and-laboratory-diagnosis","Shigella: Disease, Properties, Pathogenesis, Lab Diagnosis","2013-05-18",[],[70],"https:\u002F\u002Fassets.microbeonline.com\u002Fblogs\u002FShigella-CDC.png",{"slug":445,"title":446,"description":446,"seoTitle":44,"seoDescription":44,"author":374,"createdDate":447,"lastUpdatedDate":367,"draft":344,"category":268,"faq":448,"tags":449,"image":450},"e-coli-only-bacteria-that-wins-record-number-of-nobel-prizes","E. coli: Only bacterium that wins records number of Nobel Prizes","2013-05-04",[],[70],"https:\u002F\u002Fassets.microbeonline.com\u002Fblogs\u002FNobel-prize-for-E.-coli.jpg",{"slug":452,"title":453,"description":453,"seoTitle":44,"seoDescription":44,"author":374,"createdDate":454,"lastUpdatedDate":402,"draft":344,"category":234,"faq":455,"tags":456,"image":457},"e-coli-disease-properties-pathogenesis-and-laboratory-diagnosis","Escherichia coli: Properties and Identification","2013-04-27",[],[70],"https:\u002F\u002Fassets.microbeonline.com\u002Fblogs\u002FDifferent-strains-of-Escherichia-coli.png",{"slug":459,"title":460,"description":460,"seoTitle":44,"seoDescription":44,"author":374,"createdDate":454,"lastUpdatedDate":402,"draft":344,"category":234,"faq":461,"tags":462,"image":463},"salmonella-disease-properties-pathogenesis-and-laboratory-diagnosis","Salmonella: Properties, Disease, Lab Diagnosis",[],[70],"https:\u002F\u002Fassets.microbeonline.com\u002Fblogs\u002FClassification-of-Salmonella.jpg",{"slug":465,"title":466,"description":466,"seoTitle":44,"seoDescription":44,"author":374,"createdDate":467,"lastUpdatedDate":402,"draft":344,"category":234,"faq":468,"tags":469,"image":470},"diarrheagenic-escherichia-coli","Diarrheagenic Escherichia coli","2013-02-12",[],[70],"https:\u002F\u002Fassets.microbeonline.com\u002Fblogs\u002FEscherichia-coli-in-EMB-Agar.jpg",{"slug":472,"title":473,"description":474,"seoTitle":475,"seoDescription":476,"author":374,"createdDate":477,"lastUpdatedDate":478,"draft":344,"category":241,"faq":479,"tags":504,"image":505},"oxidase-test-principle-procedure-and-oxidase-positive-organisms","Oxidase Test: Purple in 10 Seconds, Delayed, or a False Negative?","Purple in 10 seconds is positive. Purple at 90 seconds means something else. No color at all from a TCBS or MacConkey plate often means the test failed, not that the organism is negative. Learn to read the oxidase test the way a bench microbiologist does.","Oxidase Test: 10-Second Procedure, Controls, and False Results","Perform the oxidase test within the correct reading window, use appropriate controls, and recognize media, reagent, and timing causes of false results.","2012-12-29","2026-07-22",[480,483,486,489,492,495,498,501],{"question":481,"answer":482},"What does a positive oxidase test indicate?","Presence of cytochrome c oxidase in the electron transport chain. Does NOT mean the organism is a strict aerobe — Vibrio cholerae and Campylobacter are oxidase-positive but not strict aerobes. A positive result immediately excludes the Enterobacteriaceae family, which are all oxidase-negative.",{"question":484,"answer":485},"Why are Enterobacteriaceae oxidase-negative?","They lack cytochrome c oxidase, using other terminal oxidases (cytochrome bd, cytochrome bo) that do not react with TMPD reagent. Absence of cytochrome c oxidase is a defining characteristic of the entire Enterobacteriaceae family — making the oxidase test one of the most powerful single tests for separating gram-negative rods.",{"question":487,"answer":488},"Why must the oxidase test not be performed from MacConkey agar?","A lactose-fermenting colony on MacConkey acidifies its immediate surroundings. Below roughly pH 5.1 the cytochrome c oxidase reaction cannot proceed, so a truly oxidase-positive organism reads negative. The dyes in MacConkey and EMB can also obscure color development. The error is a false negative, not a false positive. Always subculture to nutrient agar, blood agar, or tryptic soy agar first.",{"question":490,"answer":491},"Why does a nichrome wire give a false-positive oxidase result?","Nickel and iron in nichrome oxidize TMPD directly, producing the same purple endpoint that the enzyme would, but with no enzyme involved at all. The result looks identical and means nothing. Always use a platinum loop, wooden applicator stick, or plastic loop.",{"question":493,"answer":494},"What is the difference between the standard and modified oxidase (Microdase) test?","Standard oxidase test: TMPD reagent applied to gram-negative organisms — differentiates Enterobacteriaceae from non-fermenters. Modified oxidase (Microdase): TMPD in DMSO applied to gram-positive cocci — differentiates Micrococcus (positive) from Staphylococcus (negative). Standard reagent gives unreliable results with gram-positive cocci.",{"question":496,"answer":497},"Why is timing critical in the oxidase test?","TMPD undergoes spontaneous auto-oxidation in air, turning purple without any bacterial enzyme activity. Purple within 10 seconds is a true positive. Purple at 60 to 90 seconds is reported as a delayed positive. Color appearing after 2 minutes is auto-oxidation, not a result, and a reagent-only blank paper will develop the same color. Do not interpret anything after 2 minutes.",{"question":499,"answer":500},"Is Acinetobacter oxidase-positive or negative?","Oxidase-NEGATIVE — an important exception among non-fermenting gram-negative rods. Pseudomonas aeruginosa (the other major non-fermenter) is oxidase-positive. Acinetobacter oxidase-negative vs Pseudomonas oxidase-positive is one of the key distinguishing tests between these two MDR nosocomial pathogens.",{"question":502,"answer":503},"What quality control organisms are recommended for the oxidase test?","Pseudomonas aeruginosa ATCC 27853 (positive control — dark purple within 10 seconds) and Escherichia coli ATCC 25922 (negative control — remains colorless). If either control fails, discard the reagent batch, prepare fresh, and repeat controls before reporting patient results.",[70,53],"\u002Fblogs\u002FMechanism-of-the-Cytochrome-Oxidase-Reaction.png",1]