[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"$fxLN3MUwXCdr5RPjwZYIDpOj8CHyjOmngWTgoKXPtZbg":3,"$fWM8E89Icb-WHE6Cryjulg0qTxJlzDANQAgrGKtL0cco":36,"$f3Ft0rKFJHppdzE-vuveecxx1BUcg9iOlMLtyzf_MJDg":232,"$fucxFBm2ZjZfGSdmdRaSNGBI_F0jJme4f0GTvzUhQfL8":295},[4,8,12,16,20,24,28,32],{"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",{"title":33,"slug":34,"path":35},"Utilization Tests for Bacterial Identification","utilization-tests","\u002Futilization-tests\u002F",{"type":37,"data":38},"blog",{"slug":39,"title":40,"description":41,"seoTitle":42,"seoDescription":42,"author":43,"createdDate":44,"lastUpdatedDate":44,"draft":45,"category":46,"image":42,"body":47,"faq":48,"commentsClosed":45,"tags":67,"related":68,"comments":228},"antimicrobial-susceptibility-testing","Antimicrobial Susceptibility Testing (AST): Methods, Interpretation, and How to Choose","How antimicrobial susceptibility testing works, when to use disk diffusion vs. dilution vs. gradient vs. automated methods, how CLSI and EUCAST breakpoints turn a measurement into S\u002FI\u002FR, and how to read a result the way a clinician will use it.",null,"Nisha Rijal","2026-08-01",false,"bacteriology","Antimicrobial susceptibility testing (AST) answers one question a clinician cannot afford to guess at: will this drug work against this patient's organism? Everything in the microbiology lab up to this point identifies *what* is causing the infection. AST decides *what to do about it*.\n\nThe result looks deceptively simple. A report comes back reading Susceptible, Intermediate, or Resistant for each drug tested. Behind each of those letters sits a chosen method, a standardized inoculum, a defined incubation, a measured endpoint, and an interpretive breakpoint set by an expert committee. Get any of those wrong and the letter is wrong, and a wrong letter sends the wrong drug to a real patient.\n\nThis article is the map of that whole process. It covers the four families of AST methods and when each one earns its place, how a raw measurement becomes an S\u002FI\u002FR category, why CLSI and EUCAST can read the same MIC differently, and where the common interpretive traps lie. Each method and resistance mechanism has its own detailed article; this page is the overview that ties them together and points you to the right one.\n\n## Why AST exists: the gap between \"identified\" and \"treated\"\n\nIdentifying an organism narrows the drug choices but rarely settles them. Two *Escherichia coli* isolates from two patients can have opposite susceptibility profiles because resistance is acquired, mobile, and local. Empirical therapy (best guess before results) buys time, but it is a bet placed against local resistance patterns. AST replaces the bet with a measurement specific to this isolate, and lets therapy be de-escalated from a broad-spectrum guess to a targeted, narrower drug. That de-escalation is the single most important thing AST enables, and it is why the discipline now sits at the center of antimicrobial stewardship.\n\n## The four families of AST methods\n\nEvery routine method belongs to one of four families. The choice among them is a trade-off between cost, speed, and how much information you need.\n\n**Diffusion methods.** Antibiotic diffuses out of a disk into agar, creating a concentration gradient; the zone of inhibition around the disk is measured and read against a chart. This is the workhorse of most laboratories: cheap, flexible, and well-standardized. The dominant version is the modified [Kirby-Bauer disk diffusion method](https:\u002F\u002Fmicrobeonline.com\u002Fantimicrobial-susceptibility-testing-procedure-modified-kirby-bauer-method\u002F). Where a paired susceptible control strain shares the plate, the [Stokes disk diffusion method](https:\u002F\u002Fmicrobeonline.com\u002Fstokes-disc-diffusion-method-principle-procedure-interpretation-results\u002F) is used. Diffusion gives a [category (S\u002FI\u002FR)](https:\u002F\u002Fmicrobeonline.com\u002Finterpretation-susceptibility-testing-susceptible-intermediate-resistant-mean\u002F), not a number.\n\n**Dilution methods.** The organism is exposed to doubling dilutions of the drug, and the lowest concentration that stops visible growth is the minimum inhibitory concentration (MIC), an actual number in µg\u002FmL. This is done in tubes or microplates ([broth dilution method for MIC](https:\u002F\u002Fmicrobeonline.com\u002Fminimum-inhibitory-concentration-mic-broth-dilution-method-procedure-interpretation\u002F)) or in agar (agar dilution). Extending the test to subculture the clear tubes gives the minimum bactericidal concentration (MBC). Dilution is the reference standard and the only routine way to get a true MIC, which some clinical situations require.\n\n**Gradient methods.** A plastic strip carrying a pre-formed antibiotic gradient is laid on the agar; where the growth ellipse meets the strip reads off the MIC directly. The [E-test (Epsilometer test)](https:\u002F\u002Fmicrobeonline.com\u002Fe-test-epsilometer-test-principle-purpose-procedure-results-and-interpretations\u002F) combines the simplicity of a diffusion plate with the numeric MIC of a dilution method, at higher cost per test.\n\n**Automated methods.** Commercial systems (for example, VITEK 2, BD Phoenix, MicroScan) read growth in drug-containing wells photometrically and derive MICs by algorithm, coupling identification and AST with a fast turnaround. They dominate high-volume clinical labs but depend on the manufacturer's panels and still need manual methods as backup for unusual organisms and mechanisms.\n\nAlongside these sit the standardizing tools every method depends on: the inoculum is matched to a [McFarland turbidity standard ](https:\u002F\u002Fmicrobeonline.com\u002Fpreparation-mcfarland-turbidity-standards\u002F)(read by eye or by a [McFarland densitometer](https:\u002F\u002Fmicrobeonline.com\u002Fmcfarland-densitometer-parts-principle-and-operation\u002F)), and the disks themselves must be potent, which is why antimicrobial disk storage and stock\u002Fdisk preparation are treated as their own procedures.\n\n### Choosing a method: what the situation demands\n\nThe method families are not interchangeable. The right one depends on what the clinical question needs.\n\n\u003Cfigure>\n\u003Cimg src=\"https:\u002F\u002Fassets.microbeonline.com\u002Fblogs\u002Fast-method-selection-flow.png\" alt=\"Decision flowchart for selecting an antimicrobial susceptibility testing method. From an identified isolate, the key question is whether a category or a numeric MIC is needed, which depends on the infection site. A category result (S\u002FI\u002FR) leads to disk diffusion for routine isolates; a numeric MIC leads to dilution or gradient methods for deep-site infections; high-volume labs use automated systems. All methods converge on applying a CLSI or EUCAST breakpoint to convert the measurement into susceptible, intermediate, or resistant, followed by confirmatory tests for hidden resistance such as MRSA, the D-test, ESBL, and carbapenemase detection.\" width=\"2720\" height=\"1880\" draggable=\"false\" contenteditable=\"false\">\u003Cfigcaption>Choosing an AST method comes down to one question: does the clinical situation need a category or a number? A routine isolate needs only an S\u002FI\u002FR category, so disk diffusion suffices; a deep-seated infection where dosing must clear a threshold needs an exact MIC from a dilution or gradient method. Whichever method is used, the measurement means nothing until a CLSI or EUCAST breakpoint converts it into S, I, or R, and certain resistance mechanisms still need a dedicated confirmatory test.\u003C\u002Ffigcaption>\n\u003C\u002Ffigure>\n\nA routine urine or wound isolate needs a category, not a number, so disk diffusion is sufficient and economical. Endocarditis, osteomyelitis, meningitis, or a bloodstream infection in a neutropenic patient needs a precise MIC, because dosing must clear a specific threshold, so a dilution or gradient method is used. When a bactericidal drug is essential and tolerance is suspected, the MBC and the MBC\u002FMIC ratio are added.\n\nA high-volume lab that must also identify the organism fast leans on automated systems, keeping manual methods for the isolates the machine cannot call. This selection logic, matching method to clinical stakes, is the judgment an AI summary of \"what is AST\" leaves out entirely.\n\n### From measurement to meaning: breakpoints and S\u002FI\u002FR\n\nA zone diameter in millimeters or an MIC in µg\u002FmL is only a measurement. What turns it into a treatment decision is a **breakpoint**: the cutoff, set for each organism-drug pair, that divides Susceptible from Intermediate from Resistant. Breakpoints are not arbitrary lines. They fold together the wild-type MIC distribution of the species, the drug's pharmacokinetics and pharmacodynamics (whether killing is concentration-dependent or time-dependent), and the concentrations achievable at the site of infection.\n\nThis is why the same drug carries different breakpoints for different organisms, and why \"Intermediate\" is not laboratory hedging but a real pharmacological zone (often meaning the drug may work at maximum dosing or where it concentrates, such as in urine). The full logic of what Susceptible, Intermediate, and Resistant actually mean is its own topic, and it is the single most misread part of an AST report.\n\n### CLSI vs. EUCAST: two committees, sometimes two answers\n\nTwo bodies publish the breakpoints the world uses: the **Clinical and Laboratory Standards Institute (CLSI)** in the United States and the **European Committee on Antimicrobial Susceptibility Testing (EUCAST)** in Europe. They read the same evidence but can set different breakpoints, different quality-control ranges, and, for EUCAST, a distinct handling of the \"I\" category as \"Susceptible, increased exposure.\" A laboratory must pick one system and apply it consistently, because a zone diameter that reads Susceptible under one may read Intermediate under the other. Knowing which guideline a report follows is part of reading it correctly.\n\n### Detecting resistance mechanisms: when routine AST is not enough\n\nSome clinically critical resistance is invisible to a standard S\u002FI\u002FR read and needs a dedicated test. These sit downstream of the hub as their own procedures:\n\nMethicillin resistance in *Staphylococcus aureus* (MRSA) is detected with a cefoxitin surrogate, not by testing methicillin directly. Inducible clindamycin resistance hides behind an erythromycin-clindamycin discrepancy and is exposed by the D-test. In Gram-negatives, extended-spectrum beta-lactamases (ESBLs), AmpC enzymes, and carbapenemases each need specific phenotypic detection, because the routine panel can read misleadingly susceptible while a transferable enzyme lurks. The classification behind these enzymes (Ambler and Bush-Jacoby) is covered in the beta-lactamase classification article, and the confirmatory tests ([Modified Hodge](https:\u002F\u002Fmicrobeonline.com\u002Fmodified-hodge-test-mht-carbapenemase-detection-principle-method-interpretations\u002F), [Carba NP](https:\u002F\u002Fmicrobeonline.com\u002Fcarba-np-test-principle-procedure-results\u002F), phenotypic carbapenemase methods) each have their own page.\n\n### AST as the engine of stewardship\n\nAn AST result is not the end of the workflow; it is the input to a decision. Restricted (selective) reporting, releasing only the narrowest effective drugs to the clinician, steers prescribing away from broad-spectrum agents. Local AST data aggregated over time builds the antibiogram that guides empirical therapy for the next patient. And the [WHO AWaRe classification](https:\u002F\u002Fmicrobeonline.com\u002Fwho-aware-classification-antibiotics\u002F) frames which drugs to protect. This is where the laboratory stops being a service and becomes a partner in antimicrobial stewardship.\n\n## AMR\u002FAST Directory\n\n**Standardizing the test**\n\n- [Modified Kirby-Bauer disk diffusion method](https:\u002F\u002Fmicrobeonline.com\u002Fantimicrobial-susceptibility-testing-procedure-modified-kirby-bauer-method)\n- [Stokes disk diffusion method](https:\u002F\u002Fmicrobeonline.com\u002Fstokes-disc-diffusion-method-principle-procedure-interpretation-results\u002F)\n- [McFarland turbidity standards](https:\u002F\u002Fmicrobeonline.com\u002Fpreparation-mcfarland-turbidity-standards\u002F)\n- [McFarland densitometer](https:\u002F\u002Fmicrobeonline.com\u002Fmcfarland-densitometer-parts-principle-and-operation\u002F)\n- [Antibiotic stock solutions and disk preparation](https:\u002F\u002Fmicrobeonline.com\u002Fpreparation-antibiotic-stock-solutions-dried-paper-discs\u002F)\n- [Storing antimicrobial disks](https:\u002F\u002Fmicrobeonline.com\u002Fstore-commercial-antimicrobial-discs\u002F)\n- [Antimicrobial Susceptibility Testing (AST): Guidelines and Best Practices](https:\u002F\u002Fmicrobeonline.com\u002Fbasic-sets-drugs-used-routine-antimicrobial-susceptibility-testing-ast\u002F)\n\n**Measuring the MIC**\n\n- [Broth dilution method for MIC](https:\u002F\u002Fmicrobeonline.com\u002Fminimum-inhibitory-concentration-mic-broth-dilution-method-procedure-interpretation\u002F)\n- [**MIC vs. MBC**](https:\u002F\u002Fmicrobeonline.com\u002Fminimum-inhibitory-concentration-and-minimum-bactericidal-concentration-mbc\u002F)\n- [E-test (Epsilometer test)](https:\u002F\u002Fmicrobeonline.com\u002Fe-test-epsilometer-test-principle-purpose-procedure-results-and-interpretations\u002F)\n\n**Interpreting the result**\n\n- [Susceptible, Intermediate, Resistant: what they mean](https:\u002F\u002Fmicrobeonline.com\u002Finterpretation-susceptibility-testing-susceptible-intermediate-resistant-mean\u002F)\n\n**Detecting specific resistance mechanisms**\n\n- [MRSA: emergence, types, detection](https:\u002F\u002Fmicrobeonline.com\u002Fmrsa-emergence-types-detection)\n- [D-test for inducible clindamycin resistance](https:\u002F\u002Fmicrobeonline.com\u002Finducible-clindamycin-resistance-d-test-principle-procedure-and-interpretation)\n- [Beta-lactamase and ESBL classification](https:\u002F\u002Fmicrobeonline.com\u002Fbetalactamase-classification)\n- [Phenotypic methods for carbapenemase detection](https:\u002F\u002Fmicrobeonline.com\u002Fphenotypic-methods-for-the-detection-of-carbapenemases)\n- [Carba NP test](https:\u002F\u002Fmicrobeonline.com\u002Fcarba-np-test-principle-procedure-results)\n- [Modified Hodge test](https:\u002F\u002Fmicrobeonline.com\u002Fmodified-hodge-test-mht-carbapenemase-detection-principle-method-interpretations)\n\n**Stewardship**\n\n- [WHO AWaRe classification of antibiotics](https:\u002F\u002Fmicrobeonline.com\u002Fwho-aware-classification-antibiotics)\n\n## How to Remember\n\n**The one line to hold onto: identification tells you who the pathogen is**; susceptibility testing tells you *what will beat it*, and the letter on the report (S\u002FI\u002FR) is only as trustworthy as the method, the inoculum, and the breakpoint behind it.\n\n**Method-selection anchor (a single question):** \"Do I need a *number* or a *category*?\" A category (S\u002FI\u002FR) means disk diffusion is enough. A number (MIC) means a dilution or gradient method, and you reach for it precisely when the drug has to clear a threshold at a hard-to-reach site: endocarditis, osteomyelitis, meningitis. Say the sentence \"deep site needs a number\" and the method choice follows.\n\n## Key exam facts in one table\n\n| Question | Answer |\n| --- | --- |\n| What does AST determine that identification does not? | Whether a specific drug will work against this specific isolate |\n| The four families of AST methods? | Diffusion, dilution, gradient, automated |\n| Which methods give a category (S\u002FI\u002FR) vs. a number (MIC)? | Diffusion gives a category; dilution and gradient give an MIC |\n| Reference-standard method for AST? | Broth microdilution (dilution family) |\n| What is a breakpoint? | The organism-drug-specific cutoff dividing S from I from R |\n| Two bodies that set breakpoints? | CLSI (US) and EUCAST (Europe) |\n| What standardizes the inoculum? | 0.5 McFarland turbidity standard (1.5 × 10⁸ CFU\u002FmL) |\n| When is an MIC (not just S\u002FI\u002FR) needed? | Deep-seated infection where dosing must clear a threshold (endocarditis, osteomyelitis, meningitis, neutropenic sepsis) |\n| Which resistance needs detection beyond routine S\u002FI\u002FR? | MRSA (cefoxitin), inducible clindamycin (D-test), ESBL\u002FAmpC\u002Fcarbapenemase (phenotypic tests) |\n| How does AST drive stewardship? | Enables de-escalation, selective reporting, and antibiogram building |\n\n## Where Students Get Confused\n\n**\"Susceptible means the drug is strong \u002F Resistant means the drug is weak.\"** No. S\u002FI\u002FR is about *this organism versus achievable drug levels*, not the drug's inherent power. A \"weak\" old drug can read Susceptible for the right bug; a powerful drug can read Resistant.\n\n**\"Intermediate means the lab wasn't sure.\"** No. Intermediate is a defined pharmacological zone, often meaning the drug may still work at maximum dose or where it concentrates (e.g., urine). It is a real category, not a hedge.\n\n**\"MIC and zone diameter are just two ways of getting the same S\u002FI\u002FR.\"** They are read differently and are not interchangeable numbers: a small zone corresponds to a *high* MIC (more resistant). The inverse relationship trips students constantly.\n\n**\"Every isolate needs an MIC.\"** Most routine isolates need only a category, which disk diffusion supplies cheaply. The MIC is reserved for situations where the number changes management.\n\n**\"CLSI and EUCAST are basically the same.\"** They frequently differ on breakpoints and QC ranges, and EUCAST reframes \"I\" as \"Susceptible, increased exposure.\" A report is only interpretable if you know which system it follows.\n\n## References\n\n- Clinical and Laboratory Standards Institute (CLSI). *Performance Standards for Antimicrobial Susceptibility Testing.* M100, current edition. Wayne, PA: CLSI.\n- European Committee on Antimicrobial Susceptibility Testing (EUCAST). *Breakpoint tables for interpretation of MICs and zone diameters,* current version. \u003Chttps:\u002F\u002Fwww.eucast.org>\n- Tille PM. *Bailey & Scott's Diagnostic Microbiology.* 15th ed. St. Louis: Elsevier; 2022.\n- Khan ZA, Siddiqui MF, Park S. Current and Emerging Methods of Antibiotic Susceptibility Testing. *Diagnostics (Basel).* 2019;9(2):49.\n- World Health Organization. *Basic laboratory procedures in clinical bacteriology.* 2nd ed. Geneva: WHO.",[49,52,55,58,61,64],{"question":50,"answer":51},"\u003Cp>What is the difference between antimicrobial susceptibility testing and organism identification?\u003C\u002Fp>","\u003Cp>Identification determines which organism is causing the infection. Susceptibility testing determines which antibiotics will actually work against that specific isolate. Identification narrows the choices; AST decides among them, because resistance is acquired and varies from isolate to isolate.\u003C\u002Fp>",{"question":53,"answer":54},"\u003Cp>Which AST method is the gold standard?\u003C\u002Fp>","\u003Cp>Broth microdilution, a dilution method, is the reference standard because it yields an exact MIC under tightly controlled conditions. Other methods are validated against it.\u003C\u002Fp>",{"question":56,"answer":57},"\u003Cp>When is an MIC needed instead of a simple Susceptible\u002FResistant result?\u003C\u002Fp>","\u003Cp>When dosing must clear a specific threshold at a hard-to-reach site, such as endocarditis, osteomyelitis, meningitis, or bloodstream infection in an immunocompromised patient. Routine infections usually need only the S\u002FI\u002FR category.\u003C\u002Fp>",{"question":59,"answer":60},"\u003Cp>Why do CLSI and EUCAST sometimes give different results for the same organism?\u003C\u002Fp>","\u003Cp>They are independent committees that set breakpoints from the same kinds of evidence but can reach different cutoffs, quality-control ranges, and category definitions. A laboratory must apply one system consistently, and a result is only interpretable if you know which one was used.\u003C\u002Fp>",{"question":62,"answer":63},"\u003Cp>Does \"Intermediate\" mean the antibiotic will not work?\u003C\u002Fp>","\u003Cp>Not necessarily. Intermediate is a defined pharmacological category that often means the drug may still be effective at maximum dosing or at sites where it concentrates, such as the urinary tract. It reflects real pharmacology, not laboratory uncertainty.\u003C\u002Fp>",{"question":65,"answer":66},"\u003Cp>Why do some resistance mechanisms need special tests beyond routine susceptibility testing?\u003C\u002Fp>","\u003Cp>Because certain clinically critical mechanisms can read misleadingly susceptible on a standard panel. MRSA is detected with a cefoxitin surrogate, inducible clindamycin resistance with the D-test, and ESBLs, AmpC, and carbapenemases with specific phenotypic tests, so these are confirmed separately rather than trusted to the routine read.\u003C\u002Fp>",[39],[69,97,104,130,155,180,204,220],{"slug":70,"title":71,"description":72,"seoTitle":42,"seoDescription":42,"author":73,"createdDate":74,"lastUpdatedDate":75,"draft":45,"category":76,"image":42,"faq":77,"tags":96},"antimicrobial-susceptibility-testing-procedure-modified-kirby-bauer-method","Modified Kirby-Bauer Disc Diffusion Method: Procedure, Reading Rules & Common Errors","The full modified Kirby-Bauer procedure — inoculum prep, disc placement, and the three exceptions to standard zone reading that catch most students off guard, including the β-lactamase \"heaped edge\" rule.","Acharya Tankeshwar","2013-08-27","2026-07-29","general-microbiology",[78,81,84,87,90,93],{"question":79,"answer":80},"Why does incubating above 35°C invalidate oxacillin\u002Fmethicillin results?","Temperatures above 35°C can cause a methicillin-resistant Staphylococcus aureus (MRSA) isolate to falsely appear oxacillin-susceptible, leading to a misleading report and potentially ineffective treatment if a β-lactam is prescribed.",{"question":82,"answer":83},"Why is a heaped-up zone edge reported as resistant even if the zone looks otherwise normal-sized?","In β-lactamase-producing staphylococci tested against penicillin, the enzyme degrades the drug right at the zone boundary, creating a heaped-up, sharply defined edge. CLSI guidance is to report this as resistant regardless of the overall zone diameter.",{"question":85,"answer":86},"Why does agar depth matter for disc diffusion accuracy?","CLSI specifies a uniform Mueller-Hinton agar depth of approximately 4 mm. Agar poured too thin lets antibiotic diffuse further than intended, producing falsely large zones; too thick restricts diffusion and produces falsely small ones.",{"question":88,"answer":89},"What's the difference between standard Kirby-Bauer and the Stokes method?","Standard Kirby-Bauer relies on tightly standardizing inoculum density, agar depth, disc potency, and incubation temperature independently. The Stokes method instead runs a known control strain on the same plate as the test organism, comparing results directly rather than against a fixed chart — making it more forgiving of batch-to-batch variation.",{"question":91,"answer":92},"Why are sulfonamide and co-trimoxazole zones read differently from other antibiotics?","Slight bacterial growth often occurs within the inhibition zone with these drugs even in susceptible isolates. This faint growth should be ignored when reading the zone edge.",{"question":94,"answer":95},"Can disc diffusion provide an exact MIC value?","No — disc diffusion only categorizes isolates as Susceptible, Intermediate, or Resistant. For an exact MIC value, methods like E-test or broth\u002Fagar dilution are needed.",[39],{"slug":98,"title":99,"description":100,"seoTitle":42,"seoDescription":42,"author":73,"createdDate":101,"lastUpdatedDate":75,"draft":45,"category":46,"image":42,"faq":102,"tags":103},"stokes-disc-diffusion-method-principle-procedure-interpretation-results","Stokes Disc Diffusion Method: Why the Control Shares the Plate","Stokes disc diffusion runs a susceptible control strain on the same plate as the test isolate, so weak discs or off media distort both zones equally and the comparison still holds.","2014-12-28",[],[39],{"slug":105,"title":106,"description":107,"seoTitle":42,"seoDescription":42,"author":73,"createdDate":108,"lastUpdatedDate":109,"draft":45,"category":46,"image":42,"faq":110,"tags":129},"interpretation-susceptibility-testing-susceptible-intermediate-resistant-mean","Susceptible, Intermediate, or Resistant: What the Categories Actually Mean (and Why \"Intermediate\" Isn't a Maybe)","S\u002FI\u002FR isn't a fixed mm or μg\u002FmL cutoff. It's organism-and-drug-specific. Learn how breakpoints are set, why \"Intermediate\" reflects real pharmacology rather than uncertainty, and a worked clinical example.","2013-08-26","2026-08-02",[111,114,117,120,123,126],{"question":112,"answer":113},"Is a zone diameter of 20mm always \"Susceptible\"?","No. Breakpoints are specific to each organism-drug combination. The same 20mm zone can be Susceptible for one pairing and Resistant for another, so always check the correct CLSI or EUCAST breakpoint table for that exact isolate and drug.",{"question":115,"answer":116},"Does \"Intermediate\" mean the antibiotic might not work?","Not automatically. It means the drug is only reliably effective in specific situations: at infection sites where it concentrates above serum levels (like urine), or at a higher approved dose. Outside those situations, response rates are genuinely lower than for Susceptible isolates.",{"question":118,"answer":119},"What's the difference between Intermediate and Susceptible-Dose Dependent (SDD)?","Intermediate reflects a buffer zone with conditional effectiveness depending on site or dosing flexibility. SDD specifically means effectiveness depends on using the higher end of the approved dosing range, a more defined, dose-driven category introduced more recently by CLSI.",{"question":121,"answer":122},"Why does CLSI use Nonsusceptible (NS) instead of Resistant for some results?","NS is used when no resistant strains of that organism have yet been documented for that drug, so only a Susceptible breakpoint exists. A result above that breakpoint is flagged Nonsusceptible rather than confidently called Resistant.",{"question":124,"answer":125},"Why is benzylpenicillin against staphylococci reported only as Susceptible or Resistant?","Because resistance in this pairing corresponds directly to β-lactamase production, an all-or-nothing mechanism, so there's no clinically meaningful intermediate zone.",{"question":127,"answer":128},"Do CLSI and EUCAST always agree on breakpoints?","Not always. CLSI (used widely in the US and South Asia) and EUCAST (the European standard) sometimes set different breakpoints for the same drug-organism pair, based on differences in dosing practices and population MIC data, so always confirm which system a given lab report is using.",[39],{"slug":131,"title":132,"description":133,"seoTitle":42,"seoDescription":42,"author":73,"createdDate":134,"lastUpdatedDate":75,"draft":45,"category":46,"image":42,"faq":135,"tags":154},"minimum-inhibitory-concentration-mic-broth-dilution-method-procedure-interpretation","Broth Dilution Method for MIC: Macrodilution vs Microdilution, Procedure & Troubleshooting","Step-by-step broth macrodilution and microdilution procedure for MIC determination: antibiotic stock prep, 0.5 McFarland standardization, reading results, and a troubleshooting guide for the errors that actually happen at the bench.","2013-11-15",[136,139,142,145,148,151],{"question":137,"answer":138},"What's the difference between broth macrodilution and microdilution?","They follow the same principle — serial antibiotic dilutions inoculated with a standardized bacterial suspension — but macrodilution uses 1 mL per tube while microdilution uses 0.05–0.1 mL per well in a 96-well tray. Microdilution is far more common in routine clinical labs.",{"question":140,"answer":141},"Why must the inoculum be standardized to a 0.5 McFarland standard?","The MIC result depends directly on how many bacteria you start with. Too light an inoculum reads a falsely low MIC; too heavy reads a falsely high one. The 0.5 McFarland standard ensures every test starts from a comparable, known bacterial density.",{"question":143,"answer":144},"Why are reference strains like E. coli ATCC 25922 run alongside patient isolates?","They're quality-control checks. If a known reference strain's MIC falls outside its established CLSI range, it signals a problem with the test itself — inoculum, media, or technique — before patient results are trusted.",{"question":146,"answer":147},"What happens if microdilution trays are stacked too high during incubation?","Cultures at the center of a tall stack can incubate at a different temperature than intended, skewing growth and MIC readings — CLSI guidance caps stacking at four trays high.",{"question":149,"answer":150},"Can broth dilution MIC testing be automated?","Yes — systems like Vitek 2, MicroScan Walkaway, and BD Phoenix automate broth microdilution and reading, and are widely used in clinical labs alongside or instead of manual testing.",{"question":152,"answer":153},"Why might an MIC come back lower than clinically expected even with correct technique?","A few possibilities: the inoculum was too light, the cation-adjusted Mueller-Hinton broth's pH or calcium concentration is off, or there's a transcription\u002Freading error.",[39],{"slug":156,"title":157,"description":158,"seoTitle":42,"seoDescription":42,"author":73,"createdDate":159,"lastUpdatedDate":75,"draft":45,"category":46,"image":42,"faq":160,"tags":179},"e-test-epsilometer-test-principle-purpose-procedure-results-and-interpretations","E-Test (Epsilometer): Why It Beats a Plain Disc Test, Procedure & Reading Rules","E-test gives an exact MIC value, not just a Susceptible\u002FResistant call. Full procedure, strip placement, and the reading rules that trip up most students — plus how E-test strips are used to screen for ESBL.","2015-01-09",[161,164,167,170,173,176],{"question":162,"answer":163},"What's the difference between E-test and disc diffusion?","Disc diffusion gives only a category — Susceptible, Intermediate, or Resistant. E-test gives an exact MIC value in µg\u002FmL as well as the S\u002FI\u002FR category, which matters most for borderline or treatment-failure cases where the precise number changes the decision.",{"question":165,"answer":166},"Why does E-test use an exponential antibiotic gradient instead of a fixed concentration?","The continuous exponential gradient along the strip lets a single strip cover a wide range of concentrations, so the exact MIC can be read directly from where the inhibition ellipse intersects the scale, rather than testing one fixed concentration at a time.",{"question":168,"answer":169},"If the inhibition ellipse intersects at different points on either side of the strip, which value do you read?","Always read the greater (higher) value. This is a deliberately conservative rule — plates are never perfectly uniform, and erring toward the higher MIC avoids under-calling resistance.",{"question":171,"answer":172},"How is E-test used to screen for ESBL production?","Dual-ended combination strips carry the antibiotic alone on one end and the same antibiotic plus a β-lactamase inhibitor (such as clavulanic acid) on the other. A large drop in MIC on the inhibitor side compared to the antibiotic-alone side indicates ESBL production.",{"question":174,"answer":175},"Why is Mueller-Hinton agar used for E-test, and why does the depth matter?","Mueller-Hinton agar provides standardized, reproducible diffusion conditions with low inhibitor content. A uniform 4 mm depth is specified because agar depth directly affects how the antibiotic gradient diffuses, which affects the accuracy of the MIC reading.",{"question":177,"answer":178},"Is E-test used routinely on every isolate?","No — most labs reserve it for borderline, treatment-failure, or critical cases (such as confirming a borderline vancomycin MIC in MRSA) rather than running it as a routine first-line test, since disc diffusion is faster and cheaper for routine screening.",[39],{"slug":181,"title":182,"description":183,"seoTitle":184,"seoDescription":185,"author":73,"createdDate":186,"lastUpdatedDate":109,"draft":45,"category":46,"image":42,"faq":187,"tags":203},"preparation-mcfarland-turbidity-standards","McFarland Turbidity Standards: Preparation and Use in Susceptibility Testing","How McFarland turbidity standards are prepared, why the 0.5 standard (1.5 x 10^8 CFU\u002FmL) is the target for antimicrobial susceptibility testing, and how a wrong inoculum density gives false results.","McFarland Turbidity Standards: Preparation, Why 0.5 Matters for AST, and How to Match Inoculum","","2016-06-09",[188,191,194,197,200],{"question":189,"answer":190},"\u003Cp>What is a McFarland turbidity standard?\u003C\u002Fp>","\u003Cp>It is a reference suspension of known turbidity used to estimate the density of a bacterial suspension without counting individual cells. It is made by mixing barium chloride and sulfuric acid to form a barium sulfate precipitate whose cloudiness corresponds to a known cell density.\u003C\u002Fp>",{"question":192,"answer":193},"\u003Cp>Why is the 0.5 McFarland standard used for susceptibility testing?\u003C\u002Fp>","\u003Cp>Disk diffusion susceptibility testing was standardized and validated using an inoculum equivalent to 0.5 McFarland, which is about 1.5 x 10^8 CFU\u002FmL. All the zone-diameter breakpoints assume this density, so using it is what makes the result valid and comparable between laboratories.\u003C\u002Fp>",{"question":195,"answer":196},"\u003Cp>What happens if the inoculum is too dense or too light?\u003C\u002Fp>","\u003Cp>If it is too dense, the zones of inhibition come out smaller than they should and a susceptible organism can be misread as resistant. If it is too light, the zones come out larger and a resistant organism can be misread as susceptible. Both errors can misdirect treatment.\u003C\u002Fp>",{"question":198,"answer":199},"\u003Cp>How is a bacterial suspension matched to the standard?\u003C\u002Fp>","\u003Cp>Hold the suspension and the 0.5 McFarland standard side by side against a white background with contrasting black lines in good light, and compare the turbidity. Dilute if too dense, add organisms if too light, then use the adjusted suspension within 15 minutes.\u003C\u002Fp>",{"question":201,"answer":202},"\u003Cp>What is the difference between a McFarland standard and a McFarland densitometer?\u003C\u002Fp>","\u003Cp>The standard is the reference suspension or target density. The densitometer is an instrument that measures a suspension's turbidity photometrically and reports it in McFarland units, removing the need to prepare and compare against chemical standards.\u003C\u002Fp>",[39],{"slug":205,"title":206,"description":207,"seoTitle":42,"seoDescription":42,"author":208,"createdDate":209,"lastUpdatedDate":210,"draft":45,"category":211,"image":42,"faq":212,"tags":219},"mcfarland-densitometer-parts-principle-and-operation","McFarland Densitometer: Parts, Principle, and Operation","How a McFarland densitometer works: its parts, photometric principle, operation, and calibration. It reads bacterial suspension turbidity directly in McFarland units for susceptibility testing.","Ashma Shrestha","2022-11-01","2026-07-30","lab-equipment",[213,216],{"question":214,"answer":215},"\u003Cp>How does a McFarland densitometer work?\u003C\u002Fp>","\u003Cp>It passes light through a bacterial suspension and measures how much is transmitted. A denser suspension transmits less light, and the instrument converts this into a turbidity reading displayed directly in McFarland units, so no chemical standards need to be prepared.\u003C\u002Fp>",{"question":217,"answer":218},"\u003Cp>What is the difference between a McFarland densitometer and a McFarland standard?\u003C\u002Fp>","\u003Cp>The McFarland standard is a reference suspension of known turbidity (or the target density, such as 0.5). The densitometer is the instrument that measures a suspension's turbidity and reports it in McFarland units, replacing visual comparison against prepared standards.\u003C\u002Fp>",[39],{"slug":221,"title":222,"description":223,"seoTitle":42,"seoDescription":42,"author":73,"createdDate":224,"lastUpdatedDate":225,"draft":45,"category":46,"image":42,"faq":226,"tags":227},"modified-hodge-test-mht-carbapenemase-detection-principle-method-interpretations","Modified Hodge Test (MHT): Procedure, and Why CLSI No Longer Recommends It","MHT detects carbapenemase via a clover-leaf growth pattern, and CLSI dropped it from its guidelines in 2018 in favor of mCIM and Carba NP. The procedure, the limitations that led to its replacement, and where it's still used today.","2015-01-06","2026-08-18",[],[39],{"enabled":229,"threads":230,"total":231},true,[],0,[233,239,245,252,258,263,269,274,280,283,289],{"slug":234,"name":73,"description":235,"image":236,"body":237,"postCount":238},"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.*",468,{"slug":240,"name":208,"description":241,"image":242,"body":243,"postCount":244},"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.",78,{"slug":246,"name":247,"description":248,"image":249,"body":250,"postCount":251},"sushmita-baniya","Sushmita Baniya","Author \u002F Contributor","https:\u002F\u002Fassets.microbeonline.com\u002Fauthors\u002Fsushmita-baniya-1.png","Sushmita Baniya holds an M.Sc. in Medical Microbiology from Tribhuvan University (National College), with a research focus in Genetics and Molecular Biology. She is actively involved in teaching and research in the field of microbiology.",26,{"slug":253,"name":254,"description":248,"image":255,"body":256,"postCount":257},"samikshya-acharya","Samikshya Acharya","https:\u002F\u002Fassets.microbeonline.com\u002Fauthors\u002Fsamikshya-acharya.jpeg","Samikshya Sharma completed her postgraduate studies in Medical Microbiology at the Central Department of Microbiology, Tribhuvan University, Nepal. She contributes to Microbeonline with the goal of making foundational and clinical microbiology concepts clear and useful for students in medical, laboratory science, and allied health programs.",20,{"slug":259,"name":260,"description":248,"image":42,"body":261,"postCount":262},"alisha-tripathi","Alisha Tripathi","Alisha Tripathi holds an M.Sc. in Medical Microbiology from National College, Tribhuvan University. With over a year of teaching experience, her academic interests span Molecular Biology, Immunology, and Genetics.",6,{"slug":264,"name":265,"description":266,"image":42,"body":267,"postCount":268},"aastha-shrestha","Aastha Shrestha"," Author \u002F Contributor","Aastha Shrestha is a Biotechnology graduate with an M.Sc. from National College, Tribhuvan University. Her academic interests center on Molecular Biology and Immunology; two fields that are increasingly converging in modern diagnostic and clinical microbiology. \n\nShe contributes to Microbeonline with the goal of making complex concepts in these areas approachable and exam-relevant for students across medical, biotechnology, and laboratory science programs.",9,{"slug":270,"name":271,"description":272,"image":42,"body":42,"postCount":273},"guest-author","Guest Author","Guest Author \u002F Contributor",1,{"slug":275,"name":276,"description":248,"image":277,"body":278,"postCount":279},"srijana-khanal","Srijana Khanal","https:\u002F\u002Fassets.microbeonline.com\u002Fauthors\u002Fsrijana-khanal-1.png","Srijana Khanal is a microbiology educator with nearly a decade of teaching experience, including her role as faculty in the Microbiology Department at National College, NIST. \n\nHer time in the classroom has given her a clear sense of where students struggle and what explanations actually work, a perspective that directly shapes how she writes.\n\nHer academic interests span Immunology, Genetics, Basic Sciences, and Research Methodology, and she brings the same rigor to her writing that she brought to teaching. Alongside academic writing, she has a passion for creative writing -- an instinct that shows in her ability to make dense scientific material readable without sacrificing accuracy.\n\nShe contributes to Microbeonline to extend her teaching reach beyond the classroom, helping medical and laboratory science students across the region build a stronger foundation in microbiology.",17,{"slug":281,"name":282,"description":272,"image":42,"body":42,"postCount":273},"dr-poonam-acharya","Dr. Poonam Acharya",{"slug":284,"name":43,"description":285,"image":286,"body":287,"postCount":288},"nisha-rijal","Microbiologist and AMR Specialist Kathmandu, Nepal","https:\u002F\u002Fassets.microbeonline.com\u002Fauthors\u002Fnisha-rijal-1.png","Nisha Rijal is a microbiologist with nearly 15 years of frontline diagnostic and surveillance experience at the National Public Health Laboratory (NPHL), national reference laboratory under the Department of Health Services, Nepal. She currently works as an AMR Support Officer at the World Health Organization (WHO), Nepal, where her work focuses on strengthening antimicrobial resistance surveillance systems and translating AMR data into actionable public health response.\n\nHer research, published in peer-reviewed journals and cited over 220 times, spans some of the most clinically significant infectious disease challenges in Nepal and South Asia: antimicrobial resistance trends in *Vibrio cholerae* across an 11-year national surveillance dataset, sero-epidemiology of scrub typhus in patients with acute febrile illness, lower respiratory tract infections in HIV-positive patients, and gonococcal resistance surveillance. She was a contributor to Nepal's National Antimicrobial Resistance Containment Action Plan, a foundational policy document for AMR governance in Nepal. You can find list of [Nisha Rijal's article here in Google Scholar.](https:\u002F\u002Fscholar.google.com\u002Fcitations?user=N-Ruq54AAAAJ&hl=en)\n\nThis depth of experience is visible in her writing at Microbeonline. Her 53 published articles cover bacteriology, parasitology, mycology, immunology, and laboratory techniques, and are consistently among the most detailed and clinically grounded content on the site. She brings to every article the same standard that national reference laboratory work demands: methodological precision, awareness of real diagnostic constraints, and an understanding of what results actually mean for patient care in resource-limited settings.\n\nHer areas of particular expertise include antimicrobial susceptibility testing and resistance mechanism detection, quality assurance in clinical microbiology, and laboratory-based infectious disease surveillance.\n\n---\n\n*Nisha Rijal contributes to Microbeonline in a personal capacity. Her views and writing do not represent the positions of the World Health Organization or any other institution.*",54,{"slug":290,"name":291,"description":292,"image":293,"body":294,"postCount":273},"padma-shrestha","Padma Shrestha","Author","https:\u002F\u002Fassets.microbeonline.com\u002Fauthors\u002Fpadma-shrestha.png","Padma Shrestha is from Kathmandu, Nepal. She has completed Masters degree in Medical microbiology from Tribhuvan University. She has great interest in Microbiology and Molecular Biology.",[296,303,309,314,319,324,328,332,336,341,345,349,353,358,363,367,371,375,380,385,389,393,397,402,406,410,414,418,423,428,432,436,440,444,448,452,456,460,464,468,472,476,480,484,488,492,496,500,505,509,513,517,521,525,529,533,537,541,545,549,553,557,561,565,569,573,577,581,584,588],{"slug":297,"name":298,"description":299,"image":300,"body":301,"postCount":302},"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.",14,{"slug":304,"name":305,"description":306,"image":42,"body":307,"postCount":308},"microscopy","Microscopy","Microscope types, components, and microscopy techniques","These are list of blog posts related to microscopy. ",12,{"slug":310,"name":311,"description":312,"image":42,"body":42,"postCount":313},"gram-positive-cocci","Gram-Positive Cocci","Staphylococcus, Streptococcus, Enterococcus, Micrococcus — organisms, diseases, and identification tests",11,{"slug":315,"name":316,"description":317,"image":42,"body":42,"postCount":318},"gram-negative-rods","Gram-Negative Rods (Other than Enterobacteriaceae)","\u003Cp>Gram negative rods other than members of Enterobacteriaceae family such as  Pseudomonas, Acinetobacter and related organisms\u003C\u002Fp>",5,{"slug":320,"name":321,"description":322,"image":42,"body":42,"postCount":323},"gram-positive-rods","Gram-Positive Rods","Bacillus, Clostridium, Listeria, Corynebacterium, Actinomyces and related organisms",8,{"slug":325,"name":326,"description":327,"image":42,"body":42,"postCount":313},"mycobacteria","Mycobacteria","Mycobacterium tuberculosis, leprosy, atypical mycobacteria, and acid-fast organism diagnosis",{"slug":329,"name":330,"description":331,"image":42,"body":42,"postCount":313},"anaerobic-bacteriology","Anaerobic Bacteriology","Anaerobic organisms, anaerobic culture methods, and anaerobic infection diagnosis",{"slug":333,"name":334,"description":335,"image":42,"body":42,"postCount":308},"enterobacteriaceae","Enterobacteriaceae","Identification, differentiation, and clinical significance of Enterobacteriaceae family members",{"slug":337,"name":338,"description":339,"image":42,"body":42,"postCount":340},"spirochetes","Spirochetes","Treponema, Leptospira, Borrelia and spirochetal infections",7,{"slug":342,"name":343,"description":344,"image":42,"body":42,"postCount":302},"food-microbiology","Food Microbiology","Food-borne pathogens, food safety, spoilage, and preservation",{"slug":39,"name":346,"description":347,"image":42,"body":42,"postCount":348},"Antimicrobial Susceptibility Testing","Methods for testing antibiotic susceptibility in clinical microbiology",21,{"slug":350,"name":351,"description":352,"image":42,"body":42,"postCount":323},"antimicrobials-moa-amr","Antimicrobials (MOA & AMR)","Mechanisms, detection, and clinical significance of antimicrobial resistance",{"slug":354,"name":355,"description":356,"image":42,"body":42,"postCount":357},"sterilization-disinfection","Sterilization and Disinfection","Methods of sterilization and disinfection in healthcare and laboratory settings",10,{"slug":359,"name":360,"description":361,"image":42,"body":42,"postCount":362},"specimen-collection-transport","Specimen Collection and Transport","Collection, handling, and transport of clinical specimens for microbiological testing",27,{"slug":364,"name":365,"description":366,"image":42,"body":42,"postCount":348},"bacterial-structure-physiology","Bacterial Structure and Physiology","Bacterial cell structure, growth, physiology, and environmental factors affecting growth",{"slug":368,"name":369,"description":42,"image":42,"body":370,"postCount":262},"horizontal-gene-transfer","Horizontal Gene Transfer","Articles related to **Horizontal Gene Transfer**",{"slug":372,"name":373,"description":42,"image":42,"body":374,"postCount":357},"chromatography","Chromatography","Information about chromatographic techniques.",{"slug":376,"name":377,"description":378,"image":42,"body":379,"postCount":340},"electrophoresis","Electrophoresis","Information about Electrophoresis Techniques ","Detailed information  about Electrophoresis Techniques ",{"slug":381,"name":382,"description":383,"image":42,"body":384,"postCount":262},"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":386,"name":387,"description":388,"image":42,"body":42,"postCount":262},"bacteriophage","Bacteriophage","Description about Bacteriophage.",{"slug":390,"name":391,"description":392,"image":42,"body":42,"postCount":262},"malaria","Malaria","It is the collections of articles regarding malarial disease. ",{"slug":394,"name":395,"description":396,"image":42,"body":42,"postCount":262},"anaerobic-culture-techniques","Anaerobic Culture Techniques","Posts related with Anaerobic Culture Techniques.",{"slug":398,"name":399,"description":400,"image":42,"body":42,"postCount":401},"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.",19,{"slug":403,"name":404,"description":405,"image":42,"body":42,"postCount":340},"biosafety-levels","Biosafety levels ","Articles related to Biosafety Levels",{"slug":407,"name":408,"description":409,"image":42,"body":42,"postCount":318},"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. ",{"slug":411,"name":412,"description":413,"image":42,"body":42,"postCount":262},"pipette","Pipette","Posts related with Pipette. ",{"slug":415,"name":416,"description":417,"image":42,"body":42,"postCount":323},"bacteriology-mcqs","Bacteriology MCQs","This sections lists MCQs in Bacteriology.",{"slug":419,"name":420,"description":421,"image":42,"body":42,"postCount":422},"parasitology-mcqs","Parasitology MCQs","This section lists MCQs in Parasitology.",2,{"slug":424,"name":425,"description":426,"image":42,"body":42,"postCount":427},"virology-mcqs","Virology MCQs","This is the collections of Multiple Choice Questions in Virology.",4,{"slug":429,"name":430,"description":431,"image":42,"body":42,"postCount":318},"mcqs-in-microbiology","MCQs in Microbiology","This section lists the collections of Multiple Choice Questions in General Microbiology Topics. ",{"slug":433,"name":434,"description":435,"image":42,"body":42,"postCount":323},"immunology-mcqs","Immunology MCQs","In this section; we are posting collections of Multiple Choice Questions about Immunology. ",{"slug":437,"name":438,"description":439,"image":42,"body":42,"postCount":268},"microbial-curiosities","Microbial Curiosities","In this clusters, we are posting interesting and unique information about Microorganisms. ",{"slug":441,"name":442,"description":443,"image":42,"body":42,"postCount":348},"bacterial-culture-media","Bacterial Culture Media","Posts related to Bacterial Culture Media. ",{"slug":445,"name":446,"description":447,"image":42,"body":42,"postCount":262},"fungal-culture-media","Fungal Culture Media","Posts related to Fungal Culture Media.",{"slug":449,"name":450,"description":451,"image":42,"body":42,"postCount":318},"motility-test","Motility Test","This lists the procedure regarding various tests methods for bacterial motility.",{"slug":453,"name":454,"description":455,"image":42,"body":42,"postCount":357},"bacterial-enumeration","Bacterial enumeration","These posts are related to isolation and enumeration of bacteria. ",{"slug":457,"name":458,"description":459,"image":42,"body":42,"postCount":422},"gram-positive-coccobacillus","Gram-positive coccobacillus","List of Gram Positive Coccobacilli",{"slug":461,"name":462,"description":463,"image":42,"body":42,"postCount":427},"dimorphic-fungi","Dimorphic Fungi","This is about various dimorphic fungi. ",{"slug":465,"name":466,"description":467,"image":42,"body":42,"postCount":340},"bacterial-classification","Bacterial Classification","These posts are related with various approaches used for the classification of Bacteria. ",{"slug":469,"name":470,"description":471,"image":42,"body":42,"postCount":318},"immunofluorescence","Immunofluorescence ","Various Tests related to Immunofluorescence ",{"slug":473,"name":474,"description":475,"image":42,"body":42,"postCount":268},"antibody-mediated-immunity","Antibody-mediated Immunity","This clusters links the articles that are sharing insights about Antibody-mediated immunity. ",{"slug":477,"name":478,"description":479,"image":42,"body":42,"postCount":340},"hypersensitivity","Hypersensitivity","Articles related to Hypersensitivity.",{"slug":481,"name":482,"description":42,"image":42,"body":42,"postCount":483},"haemophilus","Haemophilus",3,{"slug":485,"name":486,"description":487,"image":42,"body":42,"postCount":427},"sexually-transmitted-infections-stis","Sexually transmitted infections (STIs)","This is the clusters of infections that are transmitted sexually. ",{"slug":489,"name":490,"description":491,"image":42,"body":42,"postCount":308},"adaptive-immunity","Adaptive Immunity","Blog posts related to B Cell Immunity and T Cell Immunity.",{"slug":493,"name":494,"description":495,"image":42,"body":42,"postCount":302},"fungal-diagnostics","Fungal Diagnostics","Various methods used for the Diagnosis of Fungal Infections. ",{"slug":497,"name":498,"description":499,"image":42,"body":42,"postCount":318},"laboratory-storage-and-preservation","Laboratory Storage and Preservation","Articles about Laboratory Storage of Antimicrobial Disk, Test organisms and Equipment used for this process. ",{"slug":501,"name":502,"description":503,"image":42,"body":504,"postCount":262},"laboratory-heating-equipment","Laboratory Heating Equipment","A guide to laboratory heating equipment, including hot plates, water baths, Bunsen burners, incubators, and dry baths, and how to choose the right one for each task.","Laboratory heating equipment covers the instruments that warm, melt, incubate, or sterilize samples and media in a microbiology laboratory. Each one delivers heat differently. \n\nA hot plate gives high, direct, dry heat; a water bath gives gentle, even, wet heat up to about 100°C; a Bunsen burner gives an open flame for rapid, very high heat; an incubator holds cultures at a steady temperature over hours or days; and a dry bath heats small tubes without water. Choosing the right one depends on the temperature you need, how precise it must be, and whether the sample can tolerate direct or open-flame heat.\n\nThe articles below cover each piece of heating equipment in detail, including its parts, working principle, uses, and the mistakes that most often go wrong at the bench.",{"slug":506,"name":507,"description":508,"image":42,"body":42,"postCount":323},"laboratory-glassware","Laboratory Glassware","Posts about Laboratory Glassware. ",{"slug":510,"name":511,"description":512,"image":42,"body":42,"postCount":262},"helminths","Helminths","In this section, we are covering properties, life cycle, pathogenesis and laboratory diagnosis of Helminths\u002FHelminthic infestations. ",{"slug":514,"name":515,"description":516,"image":42,"body":42,"postCount":262},"protozoan-parasite","Protozoan Parasite","In this cluster, we are covering protozoan parasites. ",{"slug":518,"name":519,"description":520,"image":42,"body":42,"postCount":273},"tests-for-gram-positive-cocci","Biochemical Tests for Gram Positive Cocci","This is the lists of Biochemical Tests that are used for Gram Positive Cocci. ",{"slug":522,"name":523,"description":524,"image":42,"body":42,"postCount":357},"bacterial-staining-technique","Bacterial Staining Technique","Lists of various staining techniques that are used to stain bacteria. ",{"slug":526,"name":527,"description":528,"image":42,"body":42,"postCount":257},"enzyme-tests","Enzyme Tests","\u003Cp>Various Biochemical Test that are based on enzymatic activity of the microorganisms. \u003C\u002Fp>",{"slug":530,"name":531,"description":532,"image":42,"body":42,"postCount":313},"carbohydrate-utilization","Carbohydrate Utilization","\u003Cp>Various biochemical tests which are related to Carbohydrate fermentation or Utilization\u003C\u002Fp>",{"slug":534,"name":535,"description":536,"image":42,"body":42,"postCount":318},"susceptibility-based-id","Susceptibility-based ID","\u003Cp>These are susceptibility based identification test such as optochin sensitivity, bacitracin sensitivity etc. \u003C\u002Fp>",{"slug":538,"name":539,"description":540,"image":42,"body":42,"postCount":427},"microbial-metabolism","Microbial Metabolism","\u003Cp>Tests about Microbial Metabolism. \u003C\u002Fp>",{"slug":542,"name":543,"description":544,"image":42,"body":42,"postCount":323},"substrate-utilization","Substrate Utilization","\u003Cp>The test in which a non-sugar carbon\u002Fnitrogen source is used or degraded (citrate, malonate, decarboxylases, indole, PAD).\u003C\u002Fp>",{"slug":546,"name":547,"description":548,"image":42,"body":42,"postCount":483},"atypical-pneumonia","Atypical Pneumonia","\u003Cp>Organisms responsible for Atypical Pneumonia. \u003C\u002Fp>",{"slug":550,"name":551,"description":552,"image":42,"body":42,"postCount":318},"antigen","Antigen","\u003Cp>Various articles related to Antigens.\u003C\u002Fp>",{"slug":554,"name":555,"description":556,"image":42,"body":42,"postCount":340},"innate-immunity","Innate Immunity","\u003Cp>Articles related to Innate Immunity. \u003C\u002Fp>",{"slug":558,"name":559,"description":560,"image":42,"body":42,"postCount":427},"respiratory-tract-infection","Respiratory Tract Infection","\u003Cp>In this cluster, you can see various etiological agents that causes respiratory tract infection. \u003C\u002Fp>",{"slug":562,"name":563,"description":564,"image":42,"body":42,"postCount":318},"torch-infection","TORCH Infection","\u003Cp>In this section; you can find articles related with TOCH infection. \u003C\u002Fp>",{"slug":566,"name":567,"description":568,"image":42,"body":42,"postCount":340},"microbiology-for-beginners","Microbiology for Beginners","\u003Cp>These articles are very basic articles, which will share general concepts in Microbiology. \u003C\u002Fp>",{"slug":570,"name":571,"description":572,"image":42,"body":42,"postCount":262},"dna-replication","DNA Replication","\u003Cp>Articles related to DNA and Replication of DNA. \u003C\u002Fp>",{"slug":574,"name":575,"description":576,"image":42,"body":42,"postCount":340},"genetic-code","Genetic Code","\u003Cp>Articles related to Genetic Code.\u003C\u002Fp>",{"slug":578,"name":579,"description":580,"image":42,"body":42,"postCount":318},"molecular-technique","Molecular Technique","\u003Cp>Posts related to Molecular Techniques. \u003C\u002Fp>",{"slug":582,"name":583,"description":42,"image":42,"body":42,"postCount":273},"colorimetric-assay","Colorimetric Assay ",{"slug":585,"name":586,"description":587,"image":42,"body":42,"postCount":318},"pharmaceutical-microbiology","Pharmaceutical Microbiology","\u003Cp>Various articles related to Pharmaceutical Microbiology\u003C\u002Fp>",{"slug":589,"name":590,"description":42,"image":42,"body":42,"postCount":483},"blood-and-immune-cells","Blood and Immune Cells"]