[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"$fxLN3MUwXCdr5RPjwZYIDpOj8CHyjOmngWTgoKXPtZbg":3,"$fNCsMwyMkd_gFzyLdsiCFu4Sbu6qBMxBYmaM_SjTVhZg":36,"$f3Ft0rKFJHppdzE-vuveecxx1BUcg9iOlMLtyzf_MJDg":311,"$fucxFBm2ZjZfGSdmdRaSNGBI_F0jJme4f0GTvzUhQfL8":375},[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},"Authors","authors","\u002Fauthors\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},"Tags","tags","\u002Ftags\u002F",{"type":37,"data":38},"blog",{"slug":39,"title":40,"description":41,"seoTitle":42,"seoDescription":43,"author":44,"createdDate":45,"lastUpdatedDate":46,"draft":47,"category":48,"image":43,"body":49,"faq":50,"commentsClosed":47,"tags":78,"related":80,"comments":307},"eswab-types-and-uses","Liquid-Based Swab Transport Systems (eSwab): Types, Uses, and Limitations","How liquid Amies transport systems like eSwab let one collection serve culture, Gram stain, and PCR, which formats exist, and the specimens they are not suitable for.","Liquid-Based Swab Transport Systems: How eSwab Works and When to Use It",null,"Sushmita Baniya","2022-11-03","2026-08-25",false,"lab-equipment","A wound swab arrives from theatre with three requests on the form: Gram stain, aerobic and anaerobic culture, and MRSA PCR. It is a single dry rayon swab in gel Amies.\n\nThe Gram stain uses it. By the time the culture plates are inoculated, most of what the swab collected is still buried in its fibers, and there is nothing left to send for PCR. The laboratory reports what it can and adds a note asking for a repeat sample. The patient has already left theatre.\n\nA liquid-based system solves exactly this. The swab releases its sample into a milliliter of liquid medium, and that milliliter can be divided. One collection, several tests, no repeat visit.\n\nA liquid-based swab transport system pairs a flocked swab with a measured volume of liquid transport medium in a screw-cap tube. The swab releases its sample into the liquid rather than holding it in fibers, which turns a single collection into a divisible specimen that several tests can share.\n\nCopan's eSwab is the most widely used example and the one most laboratories mean when they refer to the format: a nylon flocked swab supplied with 1 mL of liquid Amies. Equivalent systems are made by other manufacturers, and the working principle is the same across all of them. This article uses eSwab as the worked example while describing the category.\n\nLiquid Amies systems are suitable for aerobic, anaerobic, and fastidious bacteria. They are not suitable for viral specimens, which is covered under limitations below.\n\nThe E in eSwab stands for elute, which is the defining feature: the sample elutes off the swab into the liquid. These devices are sterilized by gamma irradiation during manufacture, so the tube and swab arrive sterile and can be opened straight into use without further preparation. [Irradiation](\u002Fradiation-sterilization-types-mechanism-applications\u002F) destroys any nucleic acid present in the device before it leaves the factory, which is what makes the system suitable for molecular testing: there is no residual microbial DNA to give a false positive. It has no effect on specimen DNA collected later, since sterilization is complete long before the swab meets a patient.\n\n## How Liquid-Based Transport Works\n\nThree things happen in a liquid-based system that do not happen in a traditional dry or gel swab.\n\n**Release instead of retention.** A traditional swab wraps fiber around a core, and sample driven into that core stays there. A flocked tip has no core, so the collected material sits near the surface and washes off almost completely on contact with liquid. What was a swab with sample trapped in it becomes a milliliter of suspension.\n\n**Divisibility.** Once the specimen is a liquid suspension, it can be aliquoted. The same collection can supply a slide for Gram stain, an inoculum for culture plates, and a volume for a molecular assay or rapid antigen test. A dry swab must be spent on whichever test is done first.\n\n**Maintenance rather than growth.** Amies is a maintenance medium, not a growth medium. It supplies buffered salts and a reducing agent to hold organisms viable in stasis without letting them multiply, so the proportions of a mixed specimen stay roughly as collected. This is why a transport medium is not simply broth: broth would let the fast growers overtake the pathogen in transit.\n\nThe liquid formulation matters here. Gel Amies also maintains organisms, but the specimen stays embedded in the swab fibers and must be eluted at the bench, which recovers only part of it. The liquid format does the elution at the moment of collection.\n\n## Formats Available\n\nLiquid-based systems are supplied in several formats, differing in the number and size of swabs rather than in the medium. All contain 1 mL of liquid Amies.\n\n### Multiple Swabs\n\n![multiple swab - Multiple Swab, Image Source:Copan](\u002Fblogs\u002Fmultiple-swab.png)Figure: Multiple Swab, Image Source:Copan\n\nA double or triple swab set. Only the nylon flocked swab carries the 80 mm breakpoint; the additional rayon or flocked swabs do not.\n\n### Single Regular\n\n![Single Regular - Single Regular, Image Source:Copan](\u002Fblogs\u002Fsingle-regular.png)Figure: Single Regular, Image Source:Copan\n\nA single nylon flocked swab with an 80 mm breakpoint.\n\n### Single Mini Tip\n\n![Single Mini Tip - Single Mini Tip, Image Source:Copan](\u002Fblogs\u002Fsingle-minitip.png)Figure: Single Mini Tip, Image Source:Copan\n\nA nylon flocked swab with a narrower tip and a breakpoint at 80 mm or 100 mm.\n\n| Format | Swab configuration | Choose it for |\n| --- | --- | --- |\n| Single regular | One nylon flocked swab, 80 mm breakpoint | Routine adult collection: throat, wound, ear, eye, genital |\n| Single minitip | One nylon flocked swab, 80 or 100 mm breakpoint, smaller tip | Nasopharyngeal collection, pediatric specimens, narrow or small sites, urethral sampling |\n| Multiple (double or triple) | One flocked swab with breakpoint plus one or two additional swabs | Sites needing more than one sampling pass, or where a spare swab allows a second site into the same tube |\n\nThe breakpoint is the scored line on the shaft. It exists so the swab can be snapped off cleanly inside the tube at a length that lets the cap seal, without the collector's fingers entering the tube or the shaft protruding.\n\n## How to collect the sample\n\n1. Put on [personal protective equipment](\u002Fpersonal-protective-equipment-ppe\u002F) like gloves and a mask before sample collection.\n2. Open the peel pouch, remove the tube and label it properly.\n3. Then unscrew the cap and remove it.\n4. Collect the sample from the patient and insert it into the bottom of the tube.\n5. Do not touch the swab shaft below the breakpoint, since anything your glove contacts there goes into the tube. Bend the shaft against the rim of the tube at the marked breakpoint until it snaps, holding the tube away from your face. The swab tip stays in the medium.\n6. Screw the cap on tightly to prevent leakage and check the label.\n7. Transport to the laboratory and process as soon as possible. If there is a delay, hold the tube at either refrigerator temperature (4 to 8°C) or room temperature (20 to 25°C); both are acceptable within the 48-hour window. Specimens for *Neisseria gonorrhoeae* culture should be processed within 24 hours, per CLSI guidance.\n\n## Why the Flocked Tip Matters Here\n\nThe liquid format only works because the swab releases its sample. A flocked tip has no internal core, so material stays near the surface and elutes almost completely into the medium, compared with roughly a tenth recovered from a traditional fiber swab. That difference is what makes several aliquots from one collection possible.\n\n![advantage of flocked swab over the fiber swab - Image source:Copan](\u002Fblogs\u002Ftraditional.png)Figure: Image source:Copan\n\nFor the full comparison of flocked and traditional fiber swab construction, see [Types of Swabs in Microbiology](https:\u002F\u002Fmicrobeonline.com\u002Ftypes-of-swabs\u002F).\n\n## Uses\n\nLiquid Amies systems are validated for a broad range of bacterial and fungal work:\n\n- Aerobic and anaerobic bacterial culture\n- Fungal culture, validated against CLSI M40-A2\n- *Staphylococcus aureus* and MRSA detection, by culture and by PCR\n- Vancomycin-resistant *Enterococcus* (VRE) screening\n- Eye, ear, throat, wound, and genital specimens\n- Gram stain directly from the eluted sample\n- Rapid antigen testing and molecular assays\n- Automated processing, since the liquid can be pipetted and handled by instruments\n\nFor anaerobes, deep wounds, and fungal infection, tissue or aspirated fluid remains the preferred specimen where it can be obtained. The system is validated for these applications and performs well among swab-based options, but it does not close the gap between a swab and tissue.\n\nLiquid Amies systems maintain bacterial viability for up to 48 hours at either room temperature (20 to 25°C) or refrigerator temperature (4 to 8°C), validated against CLSI standard M40-A2 for transport device performance. *Neisseria gonorrhoeae* is the notable exception and should be processed within 24 hours, as it is the most fragile of the commonly transported pathogens and sets the tightest limit in the CLSI guidance.\n\n## Limitations and Unsuitable Specimens\n\n**Not for viral specimens.** This is the most important limitation and the most common error. Liquid Amies is a bacterial maintenance medium. It does not contain the protein stabilizers, antibiotics, and antifungals that a viral transport medium uses to protect virions and suppress bacterial and fungal overgrowth. A respiratory specimen for influenza, RSV, or SARS-CoV-2 belongs in viral transport medium or universal transport medium, not liquid Amies. The confusion arises because both are liquid-based systems with flocked swabs and look almost identical on the shelf. Check the medium, not the swab.\n\n**A swab is still a swab.** For anaerobic culture, deep wounds, and fungal infection, tissue or aspirated fluid remains the better specimen. A liquid-based system improves what a swab can deliver; it does not make a swab equivalent to tissue. Where an aspirate can be obtained, obtain it.\n\n**Time limits still apply**. The 48-hour figure is a validated maximum under standard conditions, not a guarantee for every organism. Fastidious organisms generally recover less well the longer they sit, whatever the medium claims.\n\n**Cost.** Liquid-based systems cost substantially more per collection than a dry rayon swab in gel Amies. Where budgets are tight, they are best reserved for specimens likely to need multiple tests, fastidious organisms, and molecular workflows, rather than used as the default for every routine throat swab.\n\n**Not a growth medium.** The 1 mL of liquid Amies maintains organisms; it does not enrich them. A low-burden specimen is still a low-burden specimen on arrival.\n\n## Liquid Amies versus gel Amies versus dry swab\n\n|  | Dry swab (no medium) | Gel Amies (traditional) | Liquid Amies (eSwab type) |\n| --- | --- | --- | --- |\n| Sample recovery | Poorest; specimen dries | Partial; specimen stays in fibers | Near complete; elutes into liquid |\n| Tests per collection | One | Usually one | Several aliquots |\n| Bacterial viability | Hours at best | Up to 48 hours (organism dependent) | Up to 48 hours (organism dependent) |\n| Suits molecular testing | Depends on swab material | Elution step needed, recovery variable | Yes, direct from the liquid |\n| Suits automation | No | Limited | Yes, liquid handles readily |\n| Anaerobe recovery | Poor | Moderate | Good, reducing agent plus liquid |\n| Cost per collection | Lowest | Low | Highest |\n| Best for | Situations with no alternative | Routine single-test bacteriology | Multi-test requests, fastidious organisms, molecular workflows, automation |\n\nThe honest summary: gel Amies remains adequate and considerably cheaper for a routine single-request bacterial swab. Liquid systems earn their cost when the specimen must serve more than one test, when the organism is fastidious, or when the workflow is automated or molecular.\n\n## **How to remember**\n\n**E is for elute, and elute is the whole point.** Every advantage of the format follows from one thing: the sample comes off the swab instead of staying in it. More sample recovered, several tests from one collection, direct pipetting for automation. All of it is elution.\n\n**Liquid maintains, broth grows.** A transport medium is deliberately not nutritious. Amies holds organisms in stasis so the mix that arrives resembles the mix that was collected. Put the same specimen in broth and the fast growers would swamp the pathogen before it reached the bench.\n\n**Amies is for bacteria, VTM is for viruses.** The two systems look nearly identical, same flocked swab, same liquid, same screw-cap tube. The medium inside is entirely different. Read the label, not the swab.\n\n**One tube, ten aliquots, forty-eight hours, twenty-four for GC.** The four numbers worth carrying: 1 mL of medium, up to ten aliquots, 48 hours of viability, and the 24-hour exception for *Neisseria gonorrhoeae*.\n\n## Key exam facts in one table\n\n| Question a student actually gets asked | The answer, with the reasoning that makes it stick |\n| --- | --- |\n| What does eSwab consist of? | A nylon flocked swab and 1 mL of liquid Amies in a sterile screw-cap tube. |\n| What does the E stand for? | Elute. The sample releases from the swab into the liquid rather than staying in the fibers. |\n| Why can one collection serve several tests? | Because the specimen becomes a liquid suspension, it can be aliquoted. Up to ten aliquots from one tube, versus one test from a dry swab. |\n| How long is bacterial viability maintained? | Up to 48 hours at room (20 to 25°C) or refrigerator (4 to 8°C) temperature, validated against CLSI M40-A2. |\n| Which organism is the exception? | *Neisseria gonorrhoeae*, which should be processed within 24 hours. It is the most fragile common transport pathogen. |\n| Why is Amies a maintenance and not a growth medium? | It holds organisms viable without letting them multiply, so the proportions in a mixed specimen stay roughly as collected. |\n| Can it be used for viral specimens? | No. Liquid Amies is a bacterial medium. Viral specimens need viral or universal transport medium. |\n| Why is the device gamma irradiated? | To sterilize it and destroy any residual nucleic acid before it leaves the factory, so there is no contaminating DNA to cause a false positive in molecular testing. |\n| What is the breakpoint? | A scored line on the shaft allowing a clean snap inside the tube, so the cap seals and fingers never enter the tube. |\n| Which format for a pediatric or nasopharyngeal specimen? | The single minitip, which has a smaller tip for narrow or small sites. |\n| Liquid Amies versus gel Amies? | Gel is cheaper and adequate for a single routine bacterial request. Liquid recovers far more sample and supports multiple tests, automation, and molecular work. |\n| Is it better than tissue for anaerobes? | No. Tissue or aspirated fluid remains preferred. Liquid systems are the best swab-based option, not a replacement for tissue. |\n\n## **Where students get confused**\n\n**\"It is a liquid swab system, so it will do for a COVID or flu swab.\"** No. Liquid Amies and viral transport medium look nearly identical, both a flocked swab in a liquid-filled screw-cap tube, but Amies is a bacterial maintenance medium without the stabilizers and antimicrobials a viral specimen needs. This is the most consequential error with these devices.\n\n**\"Gamma irradiation might damage the sample.\"** Sterilization happens during manufacture, long before the device meets a patient. Its purpose is to remove any microbial DNA from the device so that molecular testing is not contaminated by it. It has no effect on the specimen collected later.\n\n**\"The medium keeps the organisms growing.\"** It deliberately does not. Amies maintains viability without supporting multiplication. If it encouraged growth, the fast-growing commensals in a mixed specimen would outcompete the pathogen during transit and the culture would misrepresent what was collected.\n\n**\"Liquid systems make swabs as good as tissue.\"** They improve swab performance considerably but do not close the gap. For anaerobes, deep wounds, and fungal infection, an aspirate or tissue is still the better specimen.\n\n**\"48 hours means any organism survives 48 hours.\"** The figure is a validated maximum under standard conditions, not a guarantee for every organism. *Neisseria gonorrhoeae* needs processing within 24 hours, and fastidious organisms generally recover less well the longer they wait.\n\n**eSwab versus flocked swab.** These are not the same thing. A flocked swab is a swab construction, available dry or with any medium. eSwab is a complete transport system that uses a flocked swab with liquid Amies.\n\n## **References**\n\n1. Vermeiren C, Marchand-Senécal X, Sheldrake E, et al. Comparison of Copan ESwab and FLOQSwab for COVID-19 diagnosis: working around a supply shortage. J Clin Microbiol. 2020;58(6):e00669-20. \u003Chttps:\u002F\u002Fdoi.org\u002F10.1128\u002FJCM.00669-20>\n2. Gandhi B, Summerbell R, Mazzulli T. Evaluation of the Copan ESwab transport system for viability of pathogenic fungi by use of a modification of Clinical and Laboratory Standards Institute document M40-A2. J Clin Microbiol. 2018;56(2):e01481-17. \u003Chttps:\u002F\u002Fdoi.org\u002F10.1128\u002FJCM.01481-17>\n3. Silbert S, Kubasek C, Uy D, Widen R. Comparison of ESwab with traditional swabs for detection of methicillin-resistant Staphylococcus aureus using two different walk-away commercial real-time PCR methods. J Clin Microbiol. 2014;52(7):2641-2643. \u003Chttps:\u002F\u002Fdoi.org\u002F10.1128\u002FJCM.00315-14>\n4. Fontana C, Favaro M, Limongi D, Pivonkova J, Favalli C. Comparison of the eSwab collection and transportation system to an Amies gel transystem for Gram stain of clinical specimens. BMC Res Notes. 2009;2:244. \u003Chttps:\u002F\u002Fdoi.org\u002F10.1186\u002F1756-0500-2-244>\n5. Clinical and Laboratory Standards Institute. Quality Control of Microbiological Transport Systems. CLSI document M40-A2. Wayne, PA: CLSI.\n6. Tille PM, editor. Bailey & Scott's Diagnostic Microbiology. 15th ed. St. Louis: Elsevier; 2022.\n7. Copan Diagnostics. ESwab collection and transport system, product literature. \u003Chttps:\u002F\u002Fwww.copanusa.com\u002Fwp-content\u002Fuploads\u002F2019\u002F07\u002FLBM-ESwab-051519.pdf>",[51,54,57,60,63,66,69,72,75],{"question":52,"answer":53},"What is eSwab and what does the E stand for?","eSwab is a liquid-based swab transport system consisting of a nylon flocked swab and 1 mL of liquid Amies medium in a sterile screw-cap tube. The E stands for elute, referring to the sample releasing off the swab into the liquid rather than remaining trapped in the fibers.",{"question":55,"answer":56},"Can I use eSwab for viral specimens such as influenza or SARS-CoV-2?","No. Liquid Amies is a bacterial maintenance medium and lacks the protein stabilizers and antimicrobials that viral transport medium provides. Viral specimens require viral transport medium or universal transport medium. The two systems look very similar, so check the medium stated on the label rather than relying on the appearance of the swab.",{"question":58,"answer":59},"How long do organisms survive in a liquid Amies system?","Up to 48 hours at either room temperature (20 to 25°C) or refrigerator temperature (4 to 8°C), validated against CLSI standard M40-A2. Neisseria gonorrhoeae is the exception and should be processed within 24 hours, since it is the most fragile of the commonly transported pathogens.",{"question":61,"answer":62},"How many tests can be run from one eSwab collection?","Because the specimen becomes a liquid suspension, it can be divided into aliquots, typically up to ten from the 1 mL supplied. One collection can therefore serve Gram stain, culture, rapid antigen testing, and molecular assays, whereas a dry swab is usually spent on the first test performed.",{"question":64,"answer":65},"Why is the device sterilized by gamma irradiation?","Sterilization during manufacture ensures the tube and swab arrive sterile and ready to use, and it destroys any residual nucleic acid in the device. That matters for molecular testing, because contaminating DNA in a collection device could produce a false positive. It happens before the swab ever meets a patient and has no effect on the specimen collected later.",{"question":67,"answer":68},"What is the difference between liquid Amies and gel Amies?","Gel Amies holds the specimen within the swab fibers, so it must be eluted at the bench and only part is recovered. Liquid Amies elutes the sample at the moment of collection, recovering far more of it and allowing multiple aliquots. Gel remains cheaper and adequate for a routine single-request bacterial swab; liquid earns its cost for multi-test requests, fastidious organisms, and molecular or automated workflows.",{"question":70,"answer":71},"Is a liquid-based swab as good as a tissue sample?","No. For anaerobic culture, deep wounds, and fungal infection, tissue or aspirated fluid remains the preferred specimen. Liquid-based systems substantially improve what a swab can deliver, but they do not make a swab equivalent to tissue.",{"question":73,"answer":74},"What is the breakpoint on the swab shaft?","A scored line that allows the shaft to be snapped cleanly once the swab is inside the tube, so the cap seals properly and the collector's fingers never enter the tube. Bend the shaft against the tube rim at the mark, holding the tube away from your face.",{"question":76,"answer":77},"Which eSwab format should I use for a pediatric or nasopharyngeal sample?","The single minitip format, which has a smaller flocked tip suited to narrow or small collection sites, pediatric patients, and urethral sampling. The single regular format suits routine adult collection from throat, wound, ear, eye, and genital sites.",[79],"specimen-collection-transport",[81,116,124,156,186,214,242,271],{"slug":82,"title":83,"description":84,"seoTitle":43,"seoDescription":43,"author":85,"createdDate":86,"lastUpdatedDate":87,"draft":47,"category":88,"image":43,"faq":89,"tags":114},"radiation-sterilization-types-mechanism-applications","Radiation Sterilization: Types, Mechanism, and Applications","Why ionizing radiation is called \"cold sterilization,\" how gamma rays made truly single-use disposable medical devices possible, and the real difference between ionizing and non-ionizing methods.","Acharya Tankeshwar","2020-04-24","2026-07-04","general-microbiology",[90,93,96,99,102,105,108,111],{"question":91,"answer":92},"What are the two types of radiation used in sterilization?","Ionizing radiation (X-rays, gamma rays, electron-beam) and non-ionizing radiation (infrared and ultraviolet light).",{"question":94,"answer":95},"Why is ionizing radiation called \"cold sterilization\"?","Because it kills microorganisms without raising the temperature of the product being sterilized, unlike heat-based sterilization methods.",{"question":97,"answer":98},"How does ionizing radiation kill microorganisms?","It generates reactive species, such as hydroxyl and hydride radicals, that damage DNA and proteins, leading to cell death.",{"question":100,"answer":101},"How does UV light kill microorganisms, and how is that different from ionizing radiation?","UV light causes two adjacent DNA bases to bond directly to each other, forming a pyrimidine dimer that blocks replication. This is a direct photochemical change, unlike ionizing radiation, which kills indirectly through free radicals generated when it ionizes atoms.",{"question":103,"answer":104},"Why is gamma radiation used to sterilize disposable medical devices?","Gamma rays penetrate deeply enough to sterilize items inside their final, sealed packaging, allowing manufacturers to produce genuinely single-use sterile devices, such as syringes, without any additional sterilization step at the point of care.",{"question":106,"answer":107},"What biological indicator is used to validate radiation sterilization?","Spores of Bacillus pumilus.",{"question":109,"answer":110},"Can UV light sterilize items inside packaging or behind glass?","No. UV radiation has poor penetration and does not pass through glass, dirt, film, or water, so it only disinfects directly exposed surfaces.",{"question":112,"answer":113},"Was UV light used during the COVID-19 pandemic?","Yes. UVC disinfection was deployed at scale, including UVC-emitting robots for hospital floors, UVC units for disinfecting buses and public transit, and UV light for disinfecting currency at some banks. Later research confirmed UVC's effectiveness against SARS-CoV-2 and other enveloped viruses.",[115],"sterilization-disinfection",{"slug":117,"title":118,"description":119,"seoTitle":43,"seoDescription":43,"author":44,"createdDate":120,"lastUpdatedDate":121,"draft":47,"category":88,"image":43,"faq":122,"tags":123},"personal-protective-equipment-ppe","Personal Protective Equipment (PPE) in the Laboratory: Types, Selection, Donning, and Doffing","Which PPE to wear for which laboratory hazard, how requirements change from BSL-1 to BSL-3, why an N95 needs fit testing and a surgical mask does not, and the correct order for putting on and removing PPE safely.","2022-06-07","2026-08-12",[],[],{"slug":125,"title":126,"description":127,"seoTitle":43,"seoDescription":43,"author":85,"createdDate":128,"lastUpdatedDate":129,"draft":47,"category":48,"image":43,"faq":130,"tags":155},"types-of-swabs","Types of Swabs in Microbiology: Materials, Design, and Which Swab to Use","Compare cotton, calcium alginate, Dacron, rayon, and nylon flocked swabs, and see which swab and shaft to use for each specimen type, from throat and wound to pertussis and GC culture.","2022-11-08","2026-07-23",[131,134,137,140,143,146,149,152],{"question":132,"answer":133},"Which swab should I use for a nasopharyngeal specimen?","A nylon flocked or Dacron swab on a flexible plastic shaft, ideally a minitip for nasopharyngeal use. Cotton, calcium alginate, and wooden shafts should all be avoided, because they either inhibit PCR, inactivate viruses, or risk injury.",{"question":135,"answer":136},"Why can't I use cotton swabs for microbiology?","Cotton fails in two independent ways. Fatty acids in the fiber are directly toxic to fastidious organisms such as Bordetella pertussis and Neisseria gonorrhoeae, and residues from cotton inhibit PCR amplification. So a cotton swab can give a false negative either by killing the organism or by blocking its detection.",{"question":138,"answer":139},"Are calcium alginate swabs still used?","They are largely obsolete in diagnostic microbiology. Calcium alginate is toxic to tissue culture, inactivates certain viruses including herpes simplex virus, is toxic to gonococci and mycoplasmas, and interferes with PCR and fluorescent antibody tests. Older textbooks recommending it for nasopharyngeal collection are out of date.",{"question":141,"answer":142},"What is a flocked swab and why is it better?","A flocked swab has short nylon fibers standing perpendicular to the applicator with no internal core, rather than fiber wound around a core. Sample stays near the surface and elutes almost completely into liquid medium. Around 90 percent of the collected sample becomes available for testing, compared with roughly 10 percent from a traditional fiber swab, and one collection can supply several tests.",{"question":144,"answer":145},"Is a flocked swab always the best choice?","No. For nucleic acid testing, nylon flocked swabs give clearly better DNA yield, more than three and a half times that of rayon. But for antigen-based point-of-care tests, which depend on protein recovery, rayon and Dacron actually perform best and cost less. The best swab depends on the assay.",{"question":147,"answer":148},"Why are wooden shafts not recommended?","Wood is toxic to several organisms including Chlamydia trachomatis and various viruses, it releases substances that inhibit PCR, and it can splinter, which is a genuine injury risk in nasopharyngeal collection. Plastic shafts are recommended for all diagnostic collection.",{"question":150,"answer":151},"Which transport medium goes with which swab?","For general bacteriology use Amies medium, with charcoal for fastidious organisms. For enteric pathogens use Cary-Blair. For viral specimens use viral or universal transport medium, since bacterial transport media are unsuitable for viruses. Liquid-based systems such as eSwab combine a flocked swab with liquid Amies for multi-test workflows.",{"question":153,"answer":154},"Is a swab as good as a tissue sample or aspirate?","No. Where tissue, pus, or a needle aspirate can be obtained, it is almost always the better specimen, because it carries more organisms, provides enough material for multiple tests, and gives better anaerobe recovery. Swabs are appropriate where the site suits them, such as the throat or nasopharynx, or where nothing better can be obtained.",[79],{"slug":157,"title":158,"description":159,"seoTitle":43,"seoDescription":43,"author":85,"createdDate":160,"lastUpdatedDate":161,"draft":47,"category":162,"image":43,"faq":163,"tags":185},"eye-specimens-collection-transport-lab-diagnosis","Eye Specimens: Collection and Transport (Conjunctival Swab, Corneal Scraping)","\u003Cp>Why you swab both eyes even when one looks normal, how the specimen changes from conjunctivitis to a corneal ulcer, why eye samples are inoculated at the bedside, and when to think fungus or \u003Cem>Acanthamoeba.\u003C\u002Fem>\u003C\u002Fp>","2026-08-15","2026-08-20","bacteriology",[164,167,170,173,176,179,182],{"question":165,"answer":166},"\u003Cp>Why should both eyes be swabbed when only one is infected?\u003C\u002Fp>","\u003Cp>The apparently normal eye acts as a control for the conjunctiva's normal flora, helping distinguish a true pathogen from a commensal. It is also frequently infected before it shows symptoms, particularly in newborns and in viral and chlamydial conjunctivitis. Use a separate swab for each eye and label them left and right.\u003C\u002Fp>",{"question":168,"answer":169},"\u003Cp>What is the difference between a conjunctival swab and a corneal scraping?\u003C\u002Fp>","\u003Cp>A conjunctival swab samples the surface for conjunctivitis. A corneal scraping samples the corneal tissue at the edge of an ulcer for keratitis, because the pathogen sits within the cornea where a surface swab cannot reach. Scrapings are collected by an ophthalmologist.\u003C\u002Fp>",{"question":171,"answer":172},"\u003Cp>Why are eye specimens inoculated onto media at the bedside?\u003C\u002Fp>","\u003Cp>Eye specimens are scanty and can dry out and lose their few organisms in transit. Inoculating blood and chocolate agar (and Sabouraud if fungus is suspected) at the patient's side recovers far more than a swab that has to travel to the lab.\u003C\u002Fp>",{"question":174,"answer":175},"\u003Cp>Why must specimens be collected before eye drops are given?\u003C\u002Fp>","\u003Cp>Topical antibiotics suppress the organisms, and topical anesthetics are themselves bacteriostatic and lower the yield. If drops were already given, a negative culture may reflect suppression rather than true absence of infection, so note any prior treatment on the request.\u003C\u002Fp>",{"question":177,"answer":178},"\u003Cp>When should fungal or Acanthamoeba keratitis be suspected, and how does that change the specimen?\u003C\u002Fp>","\u003Cp>In contact lens wearers with keratitis. Submit the contact lens, its case, and the cleaning solution along with the corneal scraping, and request special media: non-nutrient agar for \u003Cem>Acanthamoeba\u003C\u002Fem> and Sabouraud agar with a KOH or calcofluor-white preparation for fungi.\u003C\u002Fp>",{"question":180,"answer":181},"\u003Cp>What organisms are targeted in a newborn with conjunctivitis?\u003C\u002Fp>","\u003Cp>\u003Cem>Neisseria gonorrhoeae\u003C\u002Fem> and \u003Cem>Chlamydia trachomatis\u003C\u002Fem>. Gonococcal specimens follow the fragile-organism rules (bedside inoculation, no refrigeration), and Giemsa staining is used to look for chlamydial inclusion bodies. Both eyes are sampled.\u003C\u002Fp>",{"question":183,"answer":184},"\u003Cp>Should eye specimens be refrigerated if there is a delay?\u003C\u002Fp>","\u003Cp>No. Fragile organisms such as \u003Cem>Neisseria gonorrhoeae\u003C\u002Fem> and \u003Cem>Haemophilus\u003C\u002Fem> do not tolerate cold. If a swab must travel, use Amies transport medium at room temperature and deliver it quickly; bedside inoculation is better still.\u003C\u002Fp>",[79],{"slug":187,"title":188,"description":189,"seoTitle":43,"seoDescription":43,"author":85,"createdDate":190,"lastUpdatedDate":46,"draft":47,"category":162,"image":43,"faq":191,"tags":213},"throat-swab-collection-transport-lab-diagnosis","Throat Swab: Collection, Transport, and Lab Diagnosis","\u003Cp>How to take a throat swab that actually samples the tonsils and posterior pharynx, why the tongue and cheeks must be avoided, which test needs which swab, why children need a backup culture, and how to transport it.\u003C\u002Fp>","2026-08-13",[192,195,198,201,204,207,210],{"question":193,"answer":194},"\u003Cp>Where exactly should a throat swab be taken from?\u003C\u002Fp>","\u003Cp>From both tonsils (or the tonsillar beds) and the posterior pharyngeal wall, targeting any inflamed areas or exudate. Avoid the tongue, cheeks, teeth, uvula, and lips, which carry commensal flora that contaminate the specimen.\u003C\u002Fp>",{"question":196,"answer":197},"\u003Cp>Why does the patient say \"aah\" during collection?\u003C\u002Fp>","\u003Cp>Saying \"aah\" lifts the soft palate and uvula, opening the view to the tonsils and posterior pharynx, and it reduces the gag reflex. Combined with a tongue depressor and good light, it lets you sample the right surface.\u003C\u002Fp>",{"question":199,"answer":200},"\u003Cp>If a rapid strep test is negative, is a culture still needed?\u003C\u002Fp>","\u003Cp>In children and adolescents, yes. A negative rapid antigen test should be confirmed by a throat culture or molecular test, because a missed Group A strep can lead to rheumatic fever. In adults, a negative rapid test usually does not need a backup culture. A positive rapid test is reliable at any age.\u003C\u002Fp>",{"question":202,"answer":203},"\u003Cp>How should a throat swab be transported?\u003C\u002Fp>","\u003Cp>At room temperature, as soon as possible. If a delay beyond about 2 hours is expected, place the swab in Amies or Stuart's transport medium to prevent drying. Use a Dacron or rayon swab, and avoid calcium alginate if a molecular test may be run.\u003C\u002Fp>",{"question":205,"answer":206},"\u003Cp>Can a throat swab diagnose whooping cough?\u003C\u002Fp>","\u003Cp>No. \u003Cem>Bordetella pertussis\u003C\u002Fem> lives in the nasopharynx, so a nasopharyngeal swab or aspirate is required. A throat swab will miss it.\u003C\u002Fp>",{"question":208,"answer":209},"\u003Cp>When should a throat swab not be taken?\u003C\u002Fp>","\u003Cp>When epiglottitis is suspected (severe sore throat with drooling and breathing difficulty), because provoking the gag reflex can obstruct the airway. That is an emergency requiring airway management, not a swab.\u003C\u002Fp>",{"question":211,"answer":212},"\u003Cp>Why are two swabs often collected?\u003C\u002Fp>","\u003Cp>One serves the rapid test and the other is held in transport medium for a backup culture, so the patient does not have to return. Alternatively, one makes a smear while the other goes to culture. If only one swab is available, it goes to culture first.\u003C\u002Fp>",[79],{"slug":215,"title":216,"description":217,"seoTitle":43,"seoDescription":43,"author":85,"createdDate":218,"lastUpdatedDate":161,"draft":47,"category":162,"image":43,"faq":219,"tags":241},"rejection-criteria-for-microbiological-specimens","Specimen Collection and Transport in Microbiology: Principles, Guidelines, and Rejection Criteria","\u003Cp>The principles of collecting and transporting microbiology specimens, guidelines by specimen type, the transport rules that protect the sample, and the criteria a laboratory uses to reject a specimen, with links to detailed collection guides for each specimen.\u003C\u002Fp>","2021-05-04",[220,223,226,229,232,235,238],{"question":221,"answer":222},"\u003Cp>Why is specimen collection considered the most important step in microbiology?\u003C\u002Fp>","\u003Cp>Because it is the pre-analytical phase, the largest single source of laboratory error. A poorly collected specimen either misses the causative organism or grows a contaminant, so even a perfect test produces a wrong result. The quality of the specimen sets the ceiling on the quality of the result.\u003C\u002Fp>",{"question":224,"answer":225},"\u003Cp>Which microbiology specimens should never be refrigerated?\u003C\u002Fp>","\u003Cp>Blood cultures, cerebrospinal fluid, sterile body fluids, genital specimens for \u003Cem>Neisseria gonorrhoeae\u003C\u002Fem>, and most fungal specimens are kept at room temperature, because cold kills these fastidious organisms. Urine and routine swabs, by contrast, are refrigerated if processing is delayed.\u003C\u002Fp>",{"question":227,"answer":228},"\u003Cp>What are the main reasons a laboratory rejects a specimen?\u003Cbr>\u003C\u002Fp>","\u003Cp>Clerical errors (unlabeled or mislabeled specimens, missing request forms), inappropriate samples or containers (leaking containers, formalin-fixed specimens, Foley catheter tips), delay or wrong transport temperature, specimens inappropriate for the test (dry swabs, saliva instead of sputum, 24-hour pooled samples), inadequate quantity, and duplicate specimens on the same day.\u003C\u002Fp>",{"question":230,"answer":231},"\u003Cp>What is an irretrievable specimen?\u003C\u002Fp>","\u003Cp>A specimen that cannot practically be recollected, such as cerebrospinal fluid, surgical fluids and tissue, post-mortem specimens, and blood cultures. Rather than reject one of these for a minor flaw, the laboratory processes it and adds a note to the report describing the problem, so the clinician can interpret the result with appropriate caution.\u003C\u002Fp>",{"question":233,"answer":234},"\u003Cp>Why can't a mislabeled specimen be corrected over the phone?\u003C\u002Fp>","\u003Cp>Because confirming identity by telephone reintroduces the identification error the rule exists to prevent. A mislabeled specimen is either recollected, or the label is corrected in person in the laboratory, so that patient identity is verified directly.\u003C\u002Fp>",{"question":236,"answer":237},"\u003Cp>Why is a saliva-contaminated sputum rejected?\u003C\u002Fp>","\u003Cp>A sputum with many squamous epithelial cells and few neutrophils on the screening Gram stain is mostly saliva, carrying oral flora rather than the lower-respiratory pathogen. Culturing it grows contaminants, so a proper deep-cough specimen is requested instead.\u003C\u002Fp>",{"question":239,"answer":240},"\u003Cp>How soon must specimens reach the laboratory?\u003C\u002Fp>","\u003Cp>As a general rule within 2 hours, after which an unpreserved specimen may be rejected. When a delay is unavoidable, the correct transport medium or storage condition is used, room temperature for the never-refrigerate group, refrigeration for urine and routine swabs.\u003C\u002Fp>",[79],{"slug":243,"title":244,"description":245,"seoTitle":43,"seoDescription":43,"author":85,"createdDate":246,"lastUpdatedDate":161,"draft":47,"category":247,"image":43,"faq":248,"tags":270},"sample-collections-for-laboratory-diagnosis-of-fungal-infections","Sample Collection for Fungal Infections: Which Specimen, How to Collect and Transport","\u003Cp>Which specimen to collect for a suspected fungal infection by site, how to collect skin, nail, hair, blood, CSF, respiratory, urine, and tissue correctly, and the transport rule.\u003C\u002Fp>","2021-04-03","mycology",[249,252,255,258,261,264,267],{"question":250,"answer":251},"\u003Cp>Why is a skin scraping better than a swab for a suspected fungal infection?\u003C\u002Fp>","\u003Cp>The fungus lives in the keratin at the advancing edge of the lesion, not loose on the surface. A swab collects surface debris and often misses the fungus, while scraping the growing margin with a slide edge or scalpel collects the living organism. Swabs give more false-negative results for dermatophyte infections.\u003C\u002Fp>",{"question":253,"answer":254},"\u003Cp>Should fungal specimens be refrigerated if there is a delay?\u003C\u002Fp>","\u003Cp>Almost never. Skin, nail, hair, CSF, blood, and tissue are kept at room temperature. Only urine is refrigerated (at 4°C) if processing is delayed beyond 2 hours. The rule is: warm for nearly all fungal specimens, refrigerate only urine.\u003C\u002Fp>",{"question":256,"answer":257},"\u003Cp>How should nail specimens be collected?\u003C\u002Fp>","\u003Cp>From beneath the nail plate, sampling the softened subungual material from the nail bed, because that is where the fungus grows. If that is not possible, scrape away the surface of the nail and collect shavings from the deeper portions. A surface clipping alone is a poor specimen.\u003C\u002Fp>",{"question":259,"answer":260},"\u003Cp>Why must hairs be plucked rather than cut?\u003C\u002Fp>","\u003Cp>The infection is at the hair root and the base of the shaft. Cutting the hair leaves the diagnostic part on the scalp. Hairs are plucked with forceps so the root is included, and a Wood lamp can help identify which hairs to sample.\u003C\u002Fp>",{"question":262,"answer":263},"\u003Cp>Where on a ringworm lesion should the scraping be taken?\u003C\u002Fp>","\u003Cp>From the raised, red, advancing margin. The center of the lesion is often healing and holds little live fungus, while the active edge is where the fungus is growing.\u003C\u002Fp>",{"question":265,"answer":266},"\u003Cp>Can tissue for fungal culture be placed in formalin?\u003C\u002Fp>","\u003Cp>No. Formalin kills the fungus and makes culture impossible. Send fresh tissue kept moist in sterile saline for culture, and a separate portion in formalin only if histopathology is also requested.\u003C\u002Fp>",{"question":268,"answer":269},"\u003Cp>Why is a 24-hour urine sample not accepted for fungal culture?\u003C\u002Fp>","\u003Cp>Pooling urine over 24 hours lets contaminating bacteria overgrow, which obscures the fungus. A fresh first early-morning sample is preferred, refrigerated if there is a delay.\u003C\u002Fp>",[79],{"slug":272,"title":273,"description":274,"seoTitle":275,"seoDescription":43,"author":85,"createdDate":276,"lastUpdatedDate":121,"draft":47,"category":277,"image":43,"faq":278,"tags":306},"viral-transport-media-vtm","Viral Transport Media (VTM): Composition, Uses, Storage, and VTM vs UTM","What is in viral transport medium and why, how it differs from universal transport medium and bacterial media like Amies, correct storage temperatures, and the freezing mistake that destroys specimens.","Viral Transport Media (VTM): Composition, Uses, and Correct Storage","2020-03-23","culture-media",[279,282,285,288,291,294,297,300,303],{"question":280,"answer":281},"What does viral transport medium contain?","A buffered balanced salt solution to hold pH and osmolality, a protein stabilizer such as serum, albumin, or gelatin to protect virions and stop them adsorbing to the tube wall, and antimicrobials (typically an antibiotic plus an antifungal) to suppress contaminating bacteria and fungi. Some formulations include phenol red as a pH indicator.",{"question":283,"answer":284},"Can I use one swab in VTM for both viral and bacterial testing?","No. VTM contains antibiotics and an antifungal specifically to prevent bacterial and fungal overgrowth, so bacteria in that specimen will be suppressed. If both viral and bacterial investigations are needed from the same site, collect two separate specimens.",{"question":286,"answer":287},"At what temperature should VTM specimens be stored?","Hold at 2 to 8°C and process within 48 to 72 hours. If processing will be delayed beyond that, freeze at -70°C or below and transport on dry ice. Room temperature is tolerated briefly during transit but is not equivalent to refrigeration.",{"question":289,"answer":290},"Why should viral specimens never be frozen at -20°C?","A -20°C freezer sits in the temperature range where ice crystals form and grow, and frost-free models repeatedly partially thaw and refreeze their contents. This shears viral envelopes and fragments nucleic acid. A specimen held at -20°C ends up in worse condition than one kept in the refrigerator. If -70°C is unavailable, refrigerate and expedite transport instead.",{"question":292,"answer":293},"What is the difference between VTM and UTM?","Universal transport medium is formulated to support viruses together with Chlamydia, Mycoplasma, and Ureaplasma, and to serve both culture and molecular testing. In practice the terms are used almost interchangeably and most commercial VTM sold today is a universal formulation. The distinction that matters at the bench is whether the medium is a viral one or a bacterial one.",{"question":295,"answer":296},"Can I use liquid Amies (eSwab) for a viral specimen?","No. Liquid Amies is a bacterial maintenance medium and lacks the protein stabilizer and antimicrobials a viral specimen requires. The two systems look nearly identical, both a flocked swab in liquid in a screw-cap tube, so check the medium named on the label rather than the appearance of the device.",{"question":298,"answer":299},"Why is VTM suitable for Chlamydia, Mycoplasma, and Ureaplasma if they are bacteria?","Because they are osmotically fragile in the same way viruses are. Chlamydia is an obligate intracellular organism, and Mycoplasma and Ureaplasma have no cell wall at all. All three die quickly in the salt-based media used for ordinary bacteria and need the protein stabilization and buffering that VTM provides.",{"question":301,"answer":302},"What is inactivating VTM and when should it be used?","Inactivating VTM contains a lysis agent that destroys the virus on contact while preserving its nucleic acid for PCR, which reduces the biohazard for anyone handling the specimen. The trade-off is absolute: culture, isolation, and any test requiring live virus become impossible. Use it when the request is molecular only, and use non-inactivating medium when culture may be needed.",{"question":304,"answer":305},"Should CSF or urine be placed in VTM?","No. Liquid specimens including cerebrospinal fluid, bronchoalveolar lavage fluid, urine, and ocular fluids are submitted neat in a sterile container. VTM exists to keep a swab from drying out and to stabilize what is on it. Adding it to a liquid specimen only dilutes the target, which costs sensitivity in specimens where viral load is often already low.",[79],{"enabled":308,"threads":309,"total":310},true,[],0,[312,318,325,331,337,342,348,353,359,362,369],{"slug":313,"name":85,"description":314,"image":315,"body":316,"postCount":317},"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.*",481,{"slug":319,"name":320,"description":321,"image":322,"body":323,"postCount":324},"ashma-shrestha","Ashma Shrestha","SEO Copywriter and Science Communicator\nKathmandu, Nepal","https:\u002F\u002Fassets.microbeonline.com\u002Fauthors\u002Fashma-shrestha.png","Ashma Shrestha holds a Master of Science in Medical Microbiology from the Institute of Science and Technology (IOST), Tribhuvan University, Nepal, where she developed a strong foundation in virology, molecular biology, and diagnostic microbiology.\n\nShe now works as an SEO Copywriter at Resolution Digital, where she combines her scientific training with research-driven content strategy. She is certified in Google Analytics and Google Business Profile (GBP), and brings a data-informed approach to science communication writing content that is not only accurate but structured to reach and serve the students who need it most.\n\nAt microbeonline, Ashma contributes articles primarily in virology and molecular biology, areas she finds most compelling for their mechanistic depth and their growing clinical relevance. Her writing reflects the same standard the site is built on: factual rigor, clear explanation of the *why* behind microbiology concepts, and content that helps students move from memorization to genuine understanding.\n\nShe is passionate about making complex microbiological concepts accessible without sacrificing accuracy; a skill that sits at the intersection of her scientific training and her professional work in content and SEO.",79,{"slug":326,"name":44,"description":327,"image":328,"body":329,"postCount":330},"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":332,"name":333,"description":327,"image":334,"body":335,"postCount":336},"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":338,"name":339,"description":327,"image":43,"body":340,"postCount":341},"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":343,"name":344,"description":345,"image":43,"body":346,"postCount":347},"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":349,"name":350,"description":351,"image":43,"body":43,"postCount":352},"guest-author","Guest Author","Guest Author \u002F Contributor",1,{"slug":354,"name":355,"description":327,"image":356,"body":357,"postCount":358},"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.",15,{"slug":360,"name":361,"description":351,"image":43,"body":43,"postCount":352},"dr-poonam-acharya","Dr. Poonam Acharya",{"slug":363,"name":364,"description":365,"image":366,"body":367,"postCount":368},"nisha-rijal","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":370,"name":371,"description":372,"image":373,"body":374,"postCount":352},"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.",[376,383,389,394,399,404,408,412,416,421,425,430,434,438,442,446,450,454,459,464,468,472,476,481,485,489,493,497,502,507,511,515,519,524,528,532,536,540,544,548,552,556,560,564,568,572,576,580,585,589,593,597,601,605,609,613,617,621,625,629,633,637,641,645,649,653,657,661,664,668,671,674,677,680,683,686,689,692,695,698,701,704,707],{"slug":377,"name":378,"description":379,"image":380,"body":381,"postCount":382},"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":384,"name":385,"description":386,"image":43,"body":387,"postCount":388},"microscopy","Microscopy","Microscope types, components, and microscopy techniques","These are list of blog posts related to microscopy. ",12,{"slug":390,"name":391,"description":392,"image":43,"body":43,"postCount":393},"gram-positive-cocci","Gram-Positive Cocci","Staphylococcus, Streptococcus, Enterococcus, Micrococcus — organisms, diseases, and identification tests",11,{"slug":395,"name":396,"description":397,"image":43,"body":43,"postCount":398},"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":400,"name":401,"description":402,"image":43,"body":43,"postCount":403},"gram-positive-rods","Gram-Positive Rods","Bacillus, Clostridium, Listeria, Corynebacterium, Actinomyces and related organisms",8,{"slug":405,"name":406,"description":407,"image":43,"body":43,"postCount":393},"mycobacteria","Mycobacteria","Mycobacterium tuberculosis, leprosy, atypical mycobacteria, and acid-fast organism diagnosis",{"slug":409,"name":410,"description":411,"image":43,"body":43,"postCount":388},"anaerobic-bacteriology","Anaerobic Bacteriology","Anaerobic organisms, anaerobic culture methods, and anaerobic infection diagnosis",{"slug":413,"name":414,"description":415,"image":43,"body":43,"postCount":388},"enterobacteriaceae","Enterobacteriaceae","Identification, differentiation, and clinical significance of Enterobacteriaceae family members",{"slug":417,"name":418,"description":419,"image":43,"body":43,"postCount":420},"spirochetes","Spirochetes","Treponema, Leptospira, Borrelia and spirochetal infections",7,{"slug":422,"name":423,"description":424,"image":43,"body":43,"postCount":382},"food-microbiology","Food Microbiology","Food-borne pathogens, food safety, spoilage, and preservation",{"slug":426,"name":427,"description":428,"image":43,"body":43,"postCount":429},"antimicrobial-susceptibility-testing","Antimicrobial Susceptibility Testing","Methods for testing antibiotic susceptibility in clinical microbiology",21,{"slug":431,"name":432,"description":433,"image":43,"body":43,"postCount":382},"antimicrobials-moa-amr","Antimicrobials (MOA & AMR)","Mechanisms, detection, and clinical significance of antimicrobial resistance",{"slug":115,"name":435,"description":436,"image":43,"body":43,"postCount":437},"Sterilization and Disinfection","Methods of sterilization and disinfection in healthcare and laboratory settings",10,{"slug":79,"name":439,"description":440,"image":43,"body":43,"postCount":441},"Specimen Collection and Transport","Collection, handling, and transport of clinical specimens for microbiological testing",27,{"slug":443,"name":444,"description":445,"image":43,"body":43,"postCount":429},"bacterial-structure-physiology","Bacterial Structure and Physiology","Bacterial cell structure, growth, physiology, and environmental factors affecting growth",{"slug":447,"name":448,"description":43,"image":43,"body":449,"postCount":341},"horizontal-gene-transfer","Horizontal Gene Transfer","Articles related to **Horizontal Gene Transfer**",{"slug":451,"name":452,"description":43,"image":43,"body":453,"postCount":437},"chromatography","Chromatography","Information about chromatographic techniques.",{"slug":455,"name":456,"description":457,"image":43,"body":458,"postCount":420},"electrophoresis","Electrophoresis","Information about Electrophoresis Techniques ","Detailed information  about Electrophoresis Techniques ",{"slug":460,"name":461,"description":462,"image":43,"body":463,"postCount":341},"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":465,"name":466,"description":467,"image":43,"body":43,"postCount":341},"bacteriophage","Bacteriophage","Description about Bacteriophage.",{"slug":469,"name":470,"description":471,"image":43,"body":43,"postCount":341},"malaria","Malaria","It is the collections of articles regarding malarial disease. ",{"slug":473,"name":474,"description":475,"image":43,"body":43,"postCount":341},"anaerobic-culture-techniques","Anaerobic Culture Techniques","Posts related with Anaerobic Culture Techniques.",{"slug":477,"name":478,"description":479,"image":43,"body":43,"postCount":480},"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":482,"name":483,"description":484,"image":43,"body":43,"postCount":420},"biosafety-levels","Biosafety levels ","Articles related to Biosafety Levels",{"slug":486,"name":487,"description":488,"image":43,"body":43,"postCount":398},"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":490,"name":491,"description":492,"image":43,"body":43,"postCount":341},"pipette","Pipette","Posts related with Pipette. ",{"slug":494,"name":495,"description":496,"image":43,"body":43,"postCount":403},"bacteriology-mcqs","Bacteriology MCQs","This sections lists MCQs in Bacteriology.",{"slug":498,"name":499,"description":500,"image":43,"body":43,"postCount":501},"parasitology-mcqs","Parasitology MCQs","This section lists MCQs in Parasitology.",2,{"slug":503,"name":504,"description":505,"image":43,"body":43,"postCount":506},"virology-mcqs","Virology MCQs","This is the collections of Multiple Choice Questions in Virology.",4,{"slug":508,"name":509,"description":510,"image":43,"body":43,"postCount":398},"mcqs-in-microbiology","MCQs in Microbiology","This section lists the collections of Multiple Choice Questions in General Microbiology Topics. ",{"slug":512,"name":513,"description":514,"image":43,"body":43,"postCount":403},"immunology-mcqs","Immunology MCQs","In this section; we are posting collections of Multiple Choice Questions about Immunology. ",{"slug":516,"name":517,"description":518,"image":43,"body":43,"postCount":437},"microbial-curiosities","Microbial Curiosities","In this clusters, we are posting interesting and unique information about Microorganisms. ",{"slug":520,"name":521,"description":522,"image":43,"body":43,"postCount":523},"bacterial-culture-media","Bacterial Culture Media","Posts related to Bacterial Culture Media. ",23,{"slug":525,"name":526,"description":527,"image":43,"body":43,"postCount":341},"fungal-culture-media","Fungal Culture Media","Posts related to Fungal Culture Media.",{"slug":529,"name":530,"description":531,"image":43,"body":43,"postCount":398},"motility-test","Motility Test","This lists the procedure regarding various tests methods for bacterial motility.",{"slug":533,"name":534,"description":535,"image":43,"body":43,"postCount":437},"bacterial-enumeration","Bacterial enumeration","These posts are related to isolation and enumeration of bacteria. ",{"slug":537,"name":538,"description":539,"image":43,"body":43,"postCount":501},"gram-positive-coccobacillus","Gram-positive coccobacillus","List of Gram Positive Coccobacilli",{"slug":541,"name":542,"description":543,"image":43,"body":43,"postCount":506},"dimorphic-fungi","Dimorphic Fungi","This is about various dimorphic fungi. ",{"slug":545,"name":546,"description":547,"image":43,"body":43,"postCount":420},"bacterial-classification","Bacterial Classification","These posts are related with various approaches used for the classification of Bacteria. ",{"slug":549,"name":550,"description":551,"image":43,"body":43,"postCount":398},"immunofluorescence","Immunofluorescence ","Various Tests related to Immunofluorescence ",{"slug":553,"name":554,"description":555,"image":43,"body":43,"postCount":347},"antibody-mediated-immunity","Antibody-mediated Immunity","This clusters links the articles that are sharing insights about Antibody-mediated immunity. ",{"slug":557,"name":558,"description":559,"image":43,"body":43,"postCount":420},"hypersensitivity","Hypersensitivity","Articles related to Hypersensitivity.",{"slug":561,"name":562,"description":43,"image":43,"body":43,"postCount":563},"haemophilus","Haemophilus",3,{"slug":565,"name":566,"description":567,"image":43,"body":43,"postCount":506},"sexually-transmitted-infections-stis","Sexually transmitted infections (STIs)","This is the clusters of infections that are transmitted sexually. ",{"slug":569,"name":570,"description":571,"image":43,"body":43,"postCount":388},"adaptive-immunity","Adaptive Immunity","Blog posts related to B Cell Immunity and T Cell Immunity.",{"slug":573,"name":574,"description":575,"image":43,"body":43,"postCount":382},"fungal-diagnostics","Fungal Diagnostics","Various methods used for the Diagnosis of Fungal Infections. ",{"slug":577,"name":578,"description":579,"image":43,"body":43,"postCount":398},"laboratory-storage-and-preservation","Laboratory Storage and Preservation","Articles about Laboratory Storage of Antimicrobial Disk, Test organisms and Equipment used for this process. ",{"slug":581,"name":582,"description":583,"image":43,"body":584,"postCount":341},"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":586,"name":587,"description":588,"image":43,"body":43,"postCount":347},"laboratory-glassware","Laboratory Glassware","Posts about Laboratory Glassware. ",{"slug":590,"name":591,"description":592,"image":43,"body":43,"postCount":341},"helminths","Helminths","In this section, we are covering properties, life cycle, pathogenesis and laboratory diagnosis of Helminths\u002FHelminthic infestations. ",{"slug":594,"name":595,"description":596,"image":43,"body":43,"postCount":420},"protozoan-parasite","Protozoan Parasite","In this cluster, we are covering protozoan parasites. ",{"slug":598,"name":599,"description":600,"image":43,"body":43,"postCount":352},"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":602,"name":603,"description":604,"image":43,"body":43,"postCount":437},"bacterial-staining-technique","Bacterial Staining Technique","Lists of various staining techniques that are used to stain bacteria. ",{"slug":606,"name":607,"description":608,"image":43,"body":43,"postCount":429},"enzyme-tests","Enzyme Tests","\u003Cp>Various Biochemical Test that are based on enzymatic activity of the microorganisms. \u003C\u002Fp>",{"slug":610,"name":611,"description":612,"image":43,"body":43,"postCount":393},"carbohydrate-utilization","Carbohydrate Utilization","\u003Cp>Various biochemical tests which are related to Carbohydrate fermentation or Utilization\u003C\u002Fp>",{"slug":614,"name":615,"description":616,"image":43,"body":43,"postCount":398},"susceptibility-based-id","Susceptibility-based ID","\u003Cp>These are susceptibility based identification test such as optochin sensitivity, bacitracin sensitivity etc. \u003C\u002Fp>",{"slug":618,"name":619,"description":620,"image":43,"body":43,"postCount":506},"microbial-metabolism","Microbial Metabolism","\u003Cp>Tests about Microbial Metabolism. \u003C\u002Fp>",{"slug":622,"name":623,"description":624,"image":43,"body":43,"postCount":403},"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":626,"name":627,"description":628,"image":43,"body":43,"postCount":563},"atypical-pneumonia","Atypical Pneumonia","\u003Cp>Organisms responsible for Atypical Pneumonia. \u003C\u002Fp>",{"slug":630,"name":631,"description":632,"image":43,"body":43,"postCount":398},"antigen","Antigen","\u003Cp>Various articles related to Antigens.\u003C\u002Fp>",{"slug":634,"name":635,"description":636,"image":43,"body":43,"postCount":420},"innate-immunity","Innate Immunity","\u003Cp>Articles related to Innate Immunity. \u003C\u002Fp>",{"slug":638,"name":639,"description":640,"image":43,"body":43,"postCount":506},"respiratory-tract-infection","Respiratory Tract Infection","\u003Cp>In this cluster, you can see various etiological agents that causes respiratory tract infection. \u003C\u002Fp>",{"slug":642,"name":643,"description":644,"image":43,"body":43,"postCount":398},"torch-infection","TORCH Infection","\u003Cp>In this section; you can find articles related with TOCH infection. \u003C\u002Fp>",{"slug":646,"name":647,"description":648,"image":43,"body":43,"postCount":403},"microbiology-for-beginners","Microbiology for Beginners","\u003Cp>These articles are very basic articles, which will share general concepts in Microbiology. \u003C\u002Fp>",{"slug":650,"name":651,"description":652,"image":43,"body":43,"postCount":341},"dna-replication","DNA Replication","\u003Cp>Articles related to DNA and Replication of DNA. \u003C\u002Fp>",{"slug":654,"name":655,"description":656,"image":43,"body":43,"postCount":420},"genetic-code","Genetic Code","\u003Cp>Articles related to Genetic Code.\u003C\u002Fp>",{"slug":658,"name":659,"description":660,"image":43,"body":43,"postCount":420},"molecular-technique","Molecular Technique","\u003Cp>Posts related to Molecular Techniques. \u003C\u002Fp>",{"slug":662,"name":663,"description":43,"image":43,"body":43,"postCount":352},"colorimetric-assay","Colorimetric Assay ",{"slug":665,"name":666,"description":667,"image":43,"body":43,"postCount":398},"pharmaceutical-microbiology","Pharmaceutical Microbiology","\u003Cp>Various articles related to Pharmaceutical Microbiology\u003C\u002Fp>",{"slug":669,"name":670,"description":43,"image":43,"body":43,"postCount":563},"blood-and-immune-cells","Blood and Immune Cells",{"slug":672,"name":673,"description":43,"image":43,"body":43,"postCount":398},"host-pathogen-interaction","Host Pathogen Interaction",{"slug":675,"name":676,"description":43,"image":43,"body":43,"postCount":506},"blood-culture","Blood Culture",{"slug":678,"name":679,"description":43,"image":43,"body":43,"postCount":506},"environmental-microbiology","Environmental microbiology ",{"slug":681,"name":682,"description":43,"image":43,"body":43,"postCount":341},"copromicroscopic-technique","Copromicroscopic Technique",{"slug":684,"name":685,"description":43,"image":43,"body":43,"postCount":563},"quality-control","Quality Control",{"slug":687,"name":688,"description":43,"image":43,"body":43,"postCount":506},"dermatophytes","Dermatophytes",{"slug":690,"name":691,"description":43,"image":43,"body":43,"postCount":563},"viral-hemorrhagic-fevers","Viral Hemorrhagic Fevers",{"slug":693,"name":694,"description":43,"image":43,"body":43,"postCount":506},"h2s-production","H2S Production",{"slug":696,"name":697,"description":43,"image":43,"body":43,"postCount":501},"water-quality-testing","Water Quality Testing",{"slug":699,"name":700,"description":43,"image":43,"body":43,"postCount":398},"virology-basics","Virology basics",{"slug":702,"name":703,"description":43,"image":43,"body":43,"postCount":506},"typing-methods","Typing Methods",{"slug":705,"name":706,"description":43,"image":43,"body":43,"postCount":563},"blotting-technique","Blotting Technique",{"slug":708,"name":709,"description":43,"image":43,"body":43,"postCount":506},"history-microbiology","History of Microbiology"]