[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"$fxLN3MUwXCdr5RPjwZYIDpOj8CHyjOmngWTgoKXPtZbg":3,"$femRO89VYpRawrMXxDeHsG2AfIoGD8OrijPy5SzshCVA":36,"$f3Ft0rKFJHppdzE-vuveecxx1BUcg9iOlMLtyzf_MJDg":193,"$fucxFBm2ZjZfGSdmdRaSNGBI_F0jJme4f0GTvzUhQfL8":258},[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":42,"author":43,"createdDate":44,"lastUpdatedDate":45,"draft":46,"category":47,"image":42,"body":48,"faq":49,"commentsClosed":46,"tags":68,"related":70,"comments":189},"formal-ether-sedimentation-techniques"," Formal-Ether (Formalin-Ethyl Acetate) Sedimentation Technique: Principle, Procedure, and Results","\u003Cp>Step-by-step guide to the formal-ether (formalin-ethyl acetate) sedimentation technique, or FECT: principle, the four layers and which one holds the parasites, quality control, and when to choose it over flotation or Kato-Katz.\u003C\u002Fp>",null,"Acharya Tankeshwar","2012-08-03","2026-08-29",false,"parasitology","A district laboratory in rural Ethiopia receives a stool specimen from a child with chronic intermittent diarrhea. A direct saline wet mount is prepared but turns out to be negative. The clinician is not convinced. The technician then runs a formal-ether sedimentation: after centrifugation, a single *Giardia* cyst is visible in the sediment. Treatment is started.\n\nThis scenario is the reason concentration techniques exist. Direct wet mount examines roughly 2 mg of stool from a 10 to 20 g sample. Concentration techniques like formal-ether sedimentation, often abbreviated FECT (formal-ether concentration technique), process a much larger volume, physically accumulate parasites into a small sediment, and increase detection sensitivity by 3 to 5 times.\n\n![Formal Ether Sedimentation Technique - Fig-1: Formal Ether Sedimentation Technique](\u002Fblogs\u002Fformal-ether-sedimenation-technique.jpg)Figure: Fig-1: Formal Ether Sedimentation Technique\n\nThe parasitic forms of protozoa and helminths in a fecal specimen are often too few to be seen microscopically in [**direct wet mounts**](https:\u002F\u002Fmicrobeonline.com\u002Fsaline-wet-mount-diagnosis-intestinal-parasites\u002F) or in stained smear preparation. In such cases, the use of the concentration technique increases the chances of detecting parasitic organisms, thus increasing the sensitivity of copromicroscopic technique.\n\nThe two most commonly used stool concentration techniques are **sedimentation** and **flotation**. Sedimentation techniques are performed commonly in general diagnostic laboratories because they are easier to perform and less prone to technical errors.\n\n## When to Use Formal-Ether Sedimentation\n\n| Scenario | Best method |\n| --- | --- |\n| Suspected protozoa + helminths (mixed) | **Formal-ether** as it detects cysts, eggs, larvae |\n| Quantifying helminth egg burden (EPG) | Kato-Katz as it gives eggs per gram |\n| Surveillance survey for soil-transmitted helminths | Kato-Katz |\n| Suspected *Cryptosporidium*, *Giardia* (single method) | Formal-ether + modified acid-fast for *Cryptosporidium* |\n| Light-density infection, single sensitive method needed | **Formal-ether** |\n| Flotation with zinc sulfate | Used for *Giardia* cysts and some nematode eggs; not for heavy eggs (*Fasciola*, *Taenia*, unfertilized *Ascaris*) |\n\n**Key advantage over flotation:** Formal-ether detects all organisms regardless of density: heavy eggs (*Fasciola hepatica*, *Schistosoma*, unfertilized *Ascaris*) that do not float in zinc sulfate still sediment and are recovered. **This is why sedimentation is the workhorse method in general diagnostic laboratories.**\n\n## Principle of Formal Ether Sedimentation Technique\n\nSedimentation techniques **use solutions of lower specific gravity** than the parasitic organisms, thus concentrating the latter in the sediment.\n\nIt takes advantage of the high specific gravity of protozoan cysts and helminth eggs compared to water. Their natural tendency to settle out in aqueous solutions can be accelerated by light centrifugation.\n\nFormalin fixes the eggs, larvae, oocysts, and spores, so that they are no longer infectious, as well as preserves their morphology. Fecal debris is extracted into the ethyl acetate phase of the solution. Parasitic elements are sedimented at the bottom.\n\n### Materials required\n\n- Glass container\n- Gauze\n- Funnel\n- Centrifuge tube (15ml capacity)\n- Centrifuge\n- Physiological saline (0.85% w\u002Fv NaCl)\n- 10% buffered formalin\n- Ether (ethyl acetate)\n- Test tubes with stopper\n- Glass rod\n- Iodine\n- Microscope\n\n## Procedure for Formal Ether Sedimentation Technique\n\n 1. Wear gloves when handling stool specimens.\n 2. In a suitable container, thoroughly mix a portion of stool specimen about the size of a walnut into 10mL of saline solution. Mix thoroughly.\n 3. Filter the emulsion through fine mesh gauze into a conical centrifuge tube.\n 4. Centrifuge the suspension at a relative centrifugal force (RCF) of 600 g (about 2000 rpm) for no less than 10 minutes. The suspension should yield about 0.75mL of sediment for fresh specimens and 0.5 mL for formalinized feces.\n 5. Decant the supernatant and wash the sediment with 10 mL of saline solution. Centrifuge again and repeat washing until supernatant is clear.\n 6. After the last wash, decant the supernatant and add 10 mL of 10% formalin to the sediment. Mix and let stand for 5 minutes to effect fixation.\n 7. Add 1 to 2 mL of ethyl acetate. Stopper the tube and shake vigorously.\n 8. Centrifuge at 450 g RCF (about 1500 rpm) for 10 minutes. Four layers should result as follows: **a top layer of ethyl acetate; plug of debris; layer of formalin; and sediment**\n 9. Free the plug of debris from the side of the tube by ringing with an applicator stick. Carefully decant the top three layers.\n10. With a pipette, mix the remaining sediment with the small amount or remaining fluid and transfer one drop each to a drop of saline and iodine on a glass slide. Cover with a coverslip and examine microscopically for the presence of parasitic forms.\n\nAfter the final centrifugation, four layers form. **From top to bottom they are: ethyl acetate, a plug of debris, formalin, and sediment.** The parasites are in the bottom sediment layer. Every other layer is discarded. A useful way to hold the order is that the two useful things sit at the extremes: the fat solvent works at the top, the parasites collect at the bottom, and the two waste layers sit in the middle.\n\n### **What each layer contains and why it forms:**\n\n| Layer | Contents | Why it forms |\n| --- | --- | --- |\n| Top: ethyl acetate | Dissolved fats, lipids, and fat-soluble debris | Ethyl acetate (density < water) floats; extracts lipids away from parasites |\n| Plug: debris | Non-lipid organic debris (plant fibers, undigested food) | Concentrated at interface by defatting |\n| Layer: formalin | Aqueous phase with preserved parasite elements | Water-miscible formalin solution |\n| **Bottom: sediment** | **Parasitic cysts, eggs, larvae** | Heaviest elements; gravity + centrifugation pellets them |\n\n**Clinical point:** The sediment is the only layer examined. The debris plug must be freed from the tube wall and discarded cleanly. If it falls back into the sediment before decanting, it obscures the parasites below.\n\n## Quality Control\n\n1. Check solutions with each use to be sure they are clear and free of any bacterial contamination.\n2. Run known positive specimens through the procedure to verify organism recovery. This should be done at least two times per year.\n\n## Observation and Results\n\nSystematically examine the entire surface of each coverslip with the 10x  objective or, if needed for identification, higher power objectives of the microscope in a systematic manner so that the entire coverslip area is observed. When organisms or suspicious objects are seen, switch to higher magnification (40X) to see the more detailed morphology of the object in question.\n\n![Eggs of helminths - Eggs (ova) of various intestinal parasites](\u002Fblogs\u002FEggs-of-Helminth.jpg)Figure: Eggs (ova) of various intestinal parasites\n\n## Procedure Notes-sedimentation technique\n\n1. The sedimentation procedure can also be used to process polyvinyl alcohol (PVA) fixed specimens. Fill one half of a tube with the stool-PVA mixture and add 0.85% NaCl almost to the top of the tube. Then filter the mixture through wet gauze into a 15 mL centrifuge tube and follow the remaining standard procedure.\n2. If ethyl acetate is used, swab the insides of the tube with a cotton-tipped applicator stick after the plug of debris is rimmed and the excess fluid is decanted. Excess ethyl acetate in the sediment at the time smears are prepared will lead to bubbles that may obscure parasitic forms one is attempting to observe.\n3. Errors in interpretation may occur if too much or too little feces is used in the sedimentation procedure. Adhere to the recommended formula of 0.75 mL of sediment for fresh specimens and 0.5 mL for formalinized feces.\n4. Allow the centrifuge to reach maximum speed before you start timing. If the centrifugation time is too little, certain smaller parasitic forms, such as the oocysts of *Cryptosporidium* species, may not reach the sediment.\n\n## Limitation of Sedimentation Technique\n\n1. Certain parasites, such as [***Giardia lamblia***](https:\u002F\u002Fmicrobeonline.com\u002Fgiardia-lamblia-life-cycle-diseases-and-laboratory-diagnosis\u002F)**,** hookworm eggs, and *Trichuris* eggs may not concentrate well from PVA-preserved specimens. The oocysts of *Isospora belli* do not routinely appear in concentrates. Therefore, examination of permanently stained smear is highly recommended.\n2. With both the sedimentation and the flotation techniques, species identification may not be possible in all cases, depending on the clarity of the forms observed. Permanently stained smears are usually required to make the final identification, particularly when attempting to confirm the identity of the [*Entamoeba histolytica.*](\u002Fentamoeba-histolytica-life-cycle-diseases-laboratory-diagnosis\u002F)\n3. **Cryptosporidium oocysts:** *Cryptosporidium parvum* oocysts are very small (4–6 μm) and may not sediment reliably if centrifugation time or speed is insufficient. Additionally, even when present in the sediment, oocysts are not reliably identified by standard wet mount, they require a **modified acid-fast stain** applied to the sediment smear. If *Cryptosporidium* is suspected (HIV\u002FAIDS patient, traveler's diarrhea, young child), specifically request modified acid-fast staining of the formal-ether sediment. Read more about [*Cryptosporidium* in this article. ](https:\u002F\u002Fmicrobeonline.com\u002Fcryptosporidium-life-cycle-pathogenesis-lab-diagnosis\u002F)\n\n## Sedimentation vs. Flotation: Which to Choose\n\nBoth are concentration methods, and they work by opposite logic.\n\nSedimentation uses a solution of lower specific gravity than the parasites, so cysts, eggs, and larvae settle into the sediment while lighter debris stays suspended. Because everything denser than the solution sinks, sedimentation recovers parasites of every density, including heavy eggs.\n\nFlotation uses a solution of higher specific gravity than the parasites, typically zinc sulfate or a saturated salt or sugar solution. The parasites rise to the surface film and are lifted off with a coverslip, while heavier debris sinks. This gives a cleaner preparation but only for the eggs and cysts light enough to float.\n\nThe practical rule: sedimentation is the general-purpose method because it misses nothing on the basis of density, though the preparation contains more debris. Flotation gives a cleaner field but fails to recover dense eggs such as those of *Fasciola*, *Schistosoma*, operculated eggs, and unfertilized *Ascaris*, which stay at the bottom. When a single method must cover a mixed or unknown infection, sedimentation is the safer choice.\n\n| Feature | Sedimentation (formal-ether) | Flotation (zinc sulfate) |\n| --- | --- | --- |\n| Solution specific gravity | Lower than parasites | Higher than parasites |\n| Parasites collect | In the bottom sediment | In the top surface film |\n| Density coverage | All densities, nothing excluded | Only low-density eggs and cysts |\n| Heavy eggs (*Fasciola*, *Schistosoma*, unfertilized *Ascaris*) | Recovered | Missed |\n| Preparation clarity | More debris | Cleaner field |\n| Best use | General-purpose, mixed or unknown infections | Clean recovery of light eggs and cysts |\n\nFor a fuller comparison of all the stool concentration methods, including quantitative techniques, see the overview of stool concentration techniques.\n\n## How to Remember\n\n**The two extremes rule (layer order).** In the four-layer tube, the two things you care about sit at the two ends: the fat solvent floats at the very top, the parasites pack at the very bottom. The middle is waste. If you can remember \"useful at the edges, waste in the middle,\" you never confuse which layer to examine.\n\n**Sink vs. float logic.** Sedimentation makes parasites sink; flotation makes them float. The trick is what the solution does: a light solution lets heavy parasites fall (sediment), a heavy solution pushes light parasites up (flotation). The method is named for what the parasite does, not what the solution does.\n\n**Why heavy eggs betray flotation.** Picture *Fasciola* and unfertilized *Ascaris* as the \"heavy\" eggs. They are too dense to float, so a flotation method leaves them stranded at the bottom and misses them. Sedimentation, which collects everything that sinks, catches them. Heavy eggs are the reason sedimentation is the workhorse.\n\n**Formalin fixes, so no movement.** Formalin fixes and kills. Fixed things do not move. That is the one-line reason formal-ether cannot show trophozoites: they are dead and motionless. If you need to see a moving trophozoite, you need a fresh saline mount, not this method.\n\n## Where Students Actually Get Confused\n\n**1. \"Formal-ether detects trophozoites.\"** No, formalin fixation kills trophozoites and destroys motility. Formal-ether concentration is for cysts, eggs, and larvae only. To detect trophozoites, a [direct saline wet mount from fresh stool](https:\u002F\u002Fmicrobeonline.com\u002Fsaline-wet-mount-diagnosis-intestinal-parasites\u002F) processed within 30 minutes is required.\n\n**2. \"The debris plug is part of the sediment to examine.\"** The debris plug must be cleanly discarded with the other upper layers. Allowing it to fall back into the sediment obscures the parasites. The procedure note about \"ringing with an applicator stick\" is specifically to free the plug before decanting.\n\n**3. \"Ethyl acetate and diethyl ether are the same.\"** The original procedure used diethyl ether, which is highly flammable and explosive. Ethyl acetate (ethyl acetate concentration technique) replaced diethyl ether in modern laboratories for safety reasons. The principle is identical, both extract fats. The **current standard name is \"formalin-ethyl acetate sedimentation\" (FEAS);** \"formal-ether\" is the legacy name retained because of its historical prevalence in curricula.\n\n**4. \"Centrifugation time doesn't matter.\"** Too short a centrifugation fails to pellet small oocysts (*Cryptosporidium*). The recommended minimum is 10 minutes at 450–600g. Always wait for the centrifuge to reach full speed before starting the timer.\n\n**5. \"PVA-preserved specimens cannot be processed by formal-ether.\"** PVA-preserved specimens can be processed by formal-ether sedimentation using the modification described in the procedure notes. However, *Giardia* cysts, hookworm eggs, and *Trichuris* eggs may not concentrate well from PVA, fresh or formalin-preserved specimens give better results.\n\n**6. \"Flotation is more sensitive because the field is cleaner.\"** A cleaner field is not the same as higher sensitivity. Flotation gives a clean preparation, but only for eggs and cysts light enough to rise in the solution. Dense eggs (*Fasciola*, *Schistosoma*, unfertilized *Ascaris*) never reach the surface film and are missed entirely. Sedimentation looks messier but recovers parasites of every density, which is why it is preferred when the infection is mixed or unknown.\n\n## Key Exam Facts\n\n| Fact | Detail | Memory hook |\n| --- | --- | --- |\n| Principle | Differential specific gravity: parasites sediment, fats float into ethyl acetate | Heavy parasites sink; fat floats |\n| Fixative used | 10% buffered formalin | Preserves morphology; kills organisms (non-infectious) |\n| Fat solvent | Ethyl acetate (replaces diethyl ether due to safety concerns) | Extracts fecal fats into top layer |\n| Four layers after centrifugation | Ethyl acetate \u002F debris plug \u002F formalin \u002F sediment | Examine only the sediment |\n| Centrifugation | 600g × 10 min (first spin); 450g × 10 min (concentration spin) | Two-spin protocol |\n| Detects | Cysts + eggs + larvae | NOT trophozoites (killed by formalin) |\n| Does NOT detect | Trophozoites, *Cryptosporidium* reliably | Add modified acid-fast for Cryptosporidium |\n| Advantage over flotation | Recovers heavy eggs (*Fasciola*, unfertilized *Ascaris*, *Schistosoma*) | Sedimentation = all density parasites |\n| Sensitivity increase vs direct smear | 3–5× | Processes larger volume |\n| Safety note | Ethyl acetate replaced ether | Ether = fire\u002Fexplosion risk |\n\n## **References**\n\n1\\. Garcia, L. S. (2016). *Diagnostic Medical Parasitology* (6th ed.). ASM Press.\n\n2\\. Procop, G. W., Church, D. L., Hall, G. S., Janda, W. M., Koneman, E. W., Schreckenberger, P. C., & Woods, G. L. (2017). *Koneman's Color Atlas and Textbook of Diagnostic Microbiology* (7th ed.). Wolters Kluwer.\n\n3\\. Cheesbrough, M. (2006). *District Laboratory Practice in Tropical Countries* (2nd ed., Part 1). Cambridge University Press.\n\n4\\. World Health Organization. (2012). *Bench aids for the diagnosis of intestinal parasites* (2nd ed.). WHO. \u003Chttps:\u002F\u002Fapps.who.int\u002Firis\u002Fbitstream\u002Fhandle\u002F10665\u002F37323\u002F9789241544764_eng.pdf>\n\n5\\. Ritchie, L. S. (1948). An ether sedimentation technique for routine stool examinations. *Bulletin of the US Army Medical Department*, 8(4), 326.\n\n6\\. Allen, A. V. H., & Ridley, D. S. (1970). Further observations on the formol-ether concentration technique for faecal parasites. *Journal of Clinical Pathology*, 23(6), 545–546. \u003Chttps:\u002F\u002Fdoi.org\u002F10.1136\u002Fjcp.23.6.545>\n\n7\\. CDC – DPDx: Laboratory Identification of Parasites of Public Health Concern. \u003Chttps:\u002F\u002Fwww.cdc.gov\u002Fdpdx\u002Findex.html>",[50,53,56,59,62,65],{"question":51,"answer":52},"What is the principle of the formal-ether sedimentation technique?","The principle is differential specific gravity centrifugation. Formalin preserves parasitic forms and kills organisms (making them non-infectious). Ethyl acetate dissolves and removes fecal fats into the top layer. Centrifugation causes the denser parasitic elements (cysts, eggs, larvae) to sediment at the bottom, while lighter debris and fats are distributed in the upper layers. Only the sediment is examined microscopically.",{"question":54,"answer":55},"What does formal-ether sedimentation detect and what does it miss?","\u003Cp>Formal-ether sedimentation detects protozoan cysts, helminth eggs, and larvae with high sensitivity: approximately 3 to 5 times more sensitive than direct wet mount. It does not detect trophozoites (killed by formalin) and has unreliable sensitivity for \u003Cem>Cryptosporidium \u003C\u002Fem>oocysts, which require a modified acid-fast stain applied to the sediment smear.\u003C\u002Fp>",{"question":57,"answer":58},"Why is ethyl acetate used instead of ether in the modern technique?","\u003Cp>Diethyl ether, used in the original procedure, is highly flammable and has explosive vapor risk, a significant laboratory safety hazard especially near centrifuges and electrical equipment. Ethyl acetate performs the same function (dissolving fecal lipids into the top layer) without the explosion risk and has become the standard reagent in modern formalin-ethyl acetate concentration (FEAS) protocols.\u003C\u002Fp>",{"question":60,"answer":61},"\u003Cp>What does FECT mean in parasitology?\u003C\u002Fp>","\u003Cp>FECT stands for formal-ether concentration technique, also written as the formalin-ethyl acetate concentration technique. It is the stool concentration method described on this page. \"FECT\" is the abbreviation commonly used in laboratory request forms and curricula for the same procedure.\u003C\u002Fp>",{"question":63,"answer":64},"\u003Cp>Which layer contains the parasites in the formal-ether technique?\u003C\u002Fp>","\u003Cp>The parasites are in the bottom sediment layer. After the final centrifugation, four layers form: ethyl acetate at the top, a plug of debris, a formalin layer, and the sediment at the bottom. Only the sediment is examined. The top three layers are discarded.\u003C\u002Fp>",{"question":66,"answer":67},"\u003Cp>What is the difference between sedimentation and flotation for stool examination?\u003C\u002Fp>","\u003Cp>Sedimentation uses a solution lighter than the parasites, so all cysts, eggs, and larvae settle into the sediment regardless of density. Flotation uses a solution heavier than the parasites, so only light eggs and cysts rise to the surface film to be collected. Sedimentation recovers heavy eggs (\u003Cem>Fasciola\u003C\u002Fem>, \u003Cem>Schistosoma\u003C\u002Fem>, unfertilized \u003Cem>Ascaris\u003C\u002Fem>) that flotation misses, which is why it is the general-purpose method. Flotation gives a cleaner preparation but only for the parasites light enough to float.\u003C\u002Fp>",[69],"copromicroscopic-technique",[71,93,116,145,170],{"slug":72,"title":73,"description":74,"seoTitle":42,"seoDescription":42,"author":43,"createdDate":75,"lastUpdatedDate":45,"draft":46,"category":47,"image":42,"faq":76,"tags":92},"saline-wet-mount-diagnosis-intestinal-parasites","Saline Wet Mount for Intestinal Parasites: Principle, Procedure, and Results","\u003Cp>Learn how to prepare and examine a saline and iodine wet mount for intestinal parasites (trophozoites, cysts, and helminth eggs) with organism-specific results, interpretation tips, and exam mnemonics.\u003C\u002Fp>","2015-10-18",[77,80,83,86,89],{"question":78,"answer":79},"What is the difference between a saline and an iodine wet mount?","\u003Cp>A saline wet mount uses 0.85% NaCl and preserves motility, making it ideal for detecting live trophozoites of \u003Cem>Entamoeba histolytica\u003C\u002Fem>, \u003Cem>Giardia lamblia\u003C\u002Fem>, and \u003Cem>Balantidium coli,\u003C\u002Fem> as well as helminth eggs and larvae. \u003Cbr>\u003Cbr>An iodine (Lugol's) wet mount kills organisms but stains glycogen masses and nuclei, revealing the internal structure of protozoan cysts. Both preparations are made side-by-side on the same slide and examined together.\u003C\u002Fp>",{"question":81,"answer":82},"\u003Cp>How do you identify \u003Cem>Entamoeba histolytica\u003C\u002Fem> on saline wet mount?\u003C\u002Fp>","\u003Cp>\u003Cem>E. histolytica\u003C\u002Fem> trophozoites show directional, progressive motility using pseudopodia. The diagnostic hallmark is the presence of ingested red blood cells inside the cytoplasm, which indicates active tissue invasion. \u003C\u002Fp>\u003Cp>\u003C\u002Fp>\u003Cp>This distinguishes \u003Cem>E. histolytic\u003C\u002Fem>a from the morphologically identical but non-pathogenic \u003Cem>E. dispar \u003C\u002Fem>(which does not ingest RBCs) and from \u003Cem>E. coli\u003C\u002Fem> (sluggish motility, no RBC ingestion).\u003C\u002Fp>",{"question":84,"answer":85},"Why must liquid stool be examined within 30 minutes for wet mount?","Trophozoites are fragile and motile only in fresh specimens. They begin to degenerate after 30 minutes, losing motility and becoming morphologically unidentifiable. After this window, trophozoite diagnosis is unreliable. Cysts and helminth eggs are more stable and can be detected for up to 24 hours in formed stool.",{"question":87,"answer":88},"\u003Cp>Does bile affect the visibility of parasite eggs in stool?\u003C\u002Fp>","\u003Cp>Bile does not hide eggs or make them harder to detect. As an egg passes through the intestine, its shell may take up bile and turn brown or golden-yellow. This is called bile staining, and it is an aid to identification, not an obstacle. Bile-stained eggs include those of \u003Cem>Ascaris lumbricoides\u003C\u002Fem>, \u003Cem>Trichuris trichiura\u003C\u002Fem>, hookworm, and \u003Cem>Taenia\u003C\u002Fem> species. Non-bile-stained eggs, such as those of \u003Cem>Hymenolepis nana\u003C\u002Fem> and the operculated fluke eggs, remain colorless and are identified by shape and shell detail instead of color.\u003C\u002Fp>",{"question":90,"answer":91},"\u003Cp>Is the saline wet mount the same as a direct fecal smear?\u003C\u002Fp>","\u003Cp>Yes. The saline wet mount is also called the direct fecal smear or direct wet mount, and in some regions the stool examination it belongs to is called fecalysis. All refer to mixing a small portion of stool with a drop of normal saline on a slide and examining it directly under the microscope for motile trophozoites, cysts, and helminth eggs and larvae.\u003C\u002Fp>",[69],{"slug":94,"title":95,"description":96,"seoTitle":42,"seoDescription":42,"author":43,"createdDate":97,"lastUpdatedDate":45,"draft":46,"category":47,"image":42,"faq":98,"tags":114},"giardia-lamblia-life-cycle-diseases-and-laboratory-diagnosis","Giardia lamblia: Life Cycle, Pathogenesis, Treatment, and Laboratory Diagnosis","\u003Cp>How does a non-invasive parasite cause fat malabsorption and greasy diarrhea without ever entering the bloodstream? Complete \u003Cem>Giardia lamblia\u003C\u002Fem> life cycle, the brush-border mechanism, treatment, and lab diagnosis.\u003C\u002Fp>","2016-07-26",[99,102,105,108,111],{"question":100,"answer":101},"\u003Cp>How does \u003Cem>Giardia lamblia\u003C\u002Fem> cause malabsorption without invading tissue?\u003C\u002Fp>","\u003Cp>\u003Cem>Giardia lamblia\u003C\u002Fem> is non-invasive, trophozoites attach to the small intestinal mucosa via a ventral sucking disk but do not penetrate the epithelium. Malabsorption results from mechanical disruption of the brush border by dense trophozoite attachment, shortening of intestinal microvilli, and inhibition of disaccharidase enzymes, particularly lactase. Notably, the severity of symptoms does not reliably correlate with visible histological damage — much of the functional disruption occurs at a level not fully captured by routine microscopy.\u003C\u002Fp>",{"question":103,"answer":104},"\u003Cp>How is \u003Cem>Giardia lamblia\u003C\u002Fem> cyst distinguished from \u003Cem>Entamoeba histolytica\u003C\u002Fem> cyst?\u003C\u002Fp>","\u003Cp>Both organisms have four-nucleated cysts, which is a common point of confusion. The key distinguishing feature is shape: \u003Cem>Giardia lamblia \u003C\u002Fem>cysts are oval, while \u003Cem>Entamoeba histolytica\u003C\u002Fem> cysts are spherical. Nuclei count alone is insufficient to differentiate them; shape must also be assessed.\u003C\u002Fp>",{"question":106,"answer":107},"What is the treatment for giardiasis and why does treatment sometimes fail?","First-line treatment is typically metronidazole (5-7 day course) or tinidazole (single dose), with nitazoxanide and albendazole as alternatives. Treatment failure occurs in a significant proportion of cases (reported rates of 15-70% with standard metronidazole courses), due to a combination of documented drug resistance (linked to mutations in parasite enzymes that activate metronidazole), reinfection from contaminated water sources, and host factors such as IgA deficiency. Failed treatment should prompt evaluation of all these possibilities rather than assuming resistance alone.",{"question":109,"answer":110},"Why is a single stool examination often insufficient to diagnose giardiasis?","\u003Cp>\u003Cem>Giardia\u003C\u002Fem> cysts are shed intermittently in stool, so a single ova and parasite (O+P) examination misses more than 50% of giardiasis cases. Collecting three stool specimens on separate days significantly increases diagnostic sensitivity. Stool antigen ELISA testing is more sensitive and specific than microscopy alone, and the string test (Entero-Test) can be used when trophozoites are specifically suspected but not detected on stool examination.\u003C\u002Fp>",{"question":112,"answer":113},"\u003Cp>What is the difference between the trophozoite and cyst of \u003Cem>Giardia lamblia\u003C\u002Fem>?\u003C\u002Fp>","\u003Cp>The trophozoite is the active feeding stage that lives in the small intestine and causes disease. It is pear-shaped, has two nuclei and four pairs of flagella, and attaches to the mucosa by a ventral sucking disk. The cyst is the dormant, infective stage passed in the stool. It is oval, thick-walled, and contains four nuclei in the mature form. The cyst transmits the infection because it survives outside the body and tolerates chlorine, while the trophozoite is fragile and causes the symptoms once it emerges in the intestine.\u003C\u002Fp>",[115],"protozoan-parasite",{"slug":117,"title":118,"description":119,"seoTitle":42,"seoDescription":42,"author":43,"createdDate":120,"lastUpdatedDate":121,"draft":46,"category":47,"image":42,"faq":122,"tags":144},"entamoeba-histolytica-life-cycle-diseases-laboratory-diagnosis","Entamoeba histolytica: Life Cycle, Pathogenesis, Liver Abscess, and Laboratory Diagnosis","\u003Cp>How does a swallowed cyst cause both bloody dysentery and a liver abscess months later? Complete \u003Cem>Entamoeba histolytica\u003C\u002Fem> life cycle, flask-shaped ulcer mechanism, and lab diagnosis  including how to tell it apart from\u003Cem> E. dispar\u003C\u002Fem> and \u003Cem>E. coli.\u003C\u002Fem>\u003C\u002Fp>","2016-06-10","2026-08-31",[123,126,129,132,135,138,141],{"question":124,"answer":125},"\u003Cp>How does \u003Cem>Entamoeba histolytica\u003C\u002Fem> cause both intestinal disease and liver abscess?\u003C\u002Fp>","The species name describes the mechanism: 'Histo' (tissue) + 'Lytica' (lysis) refers to a tissue-lysing enzymatic action that is not site-specific. Trophozoites lyse colonic mucosa to form the characteristic flask-shaped ulcer in the intestine. Some trophozoites are then carried via the portal vein circulation to the liver, where the same cytolytic action destroys hepatocytes, leading to thrombosis of portal venules and the formation of a liver abscess.",{"question":127,"answer":128},"\u003Cp>How is \u003Cem>Entamoeba histolytica \u003C\u002Fem>distinguished from \u003Cem>Entamoeba dispar\u003C\u002Fem>?\u003C\u002Fp>","\u003Cp>Trophozoites and cysts of \u003Cem>E. histolytica\u003C\u002Fem> and\u003Cem> E. dispar\u003C\u002Fem> are morphologically identical under light microscopy. \u003Cem>E. dispar\u003C\u002Fem> is a genetically distinct, non-pathogenic species. They can only be reliably distinguished using antigen detection tests (such as ELISA for the Gal\u002FGalNAc lectin) or PCR-based molecular methods, both of which are specific to \u003Cem>E. histolytica\u003C\u002Fem> and do not cross-react with \u003Cem>E. dispar.\u003C\u002Fem>\u003C\u002Fp>",{"question":130,"answer":131},"Why is the treatment of invasive amoebiasis a two-drug sequence rather than metronidazole alone?","Metronidazole (or tinidazole) effectively treats invasive tissue disease but has limited activity against the parasite remaining in the intestinal lumen. A luminal agent such as diloxanide furoate or paromomycin must be given afterward to eliminate any residual intraluminal cysts or trophozoites. Without this second step, the patient risks relapse of disease and continues to shed infectious cysts, transmitting the infection to others.",{"question":133,"answer":134},"Can a patient have an amoebic liver abscess without ever having had diarrhoea?","Yes. Approximately 50% of patients with amoebic liver abscess have no preceding history of overt intestinal amoebiasis or dysentery. The absence of a diarrhoeal history should not lower clinical suspicion for amoebic liver abscess in a patient with a compatible presentation (right upper quadrant pain, fever, tender enlarged liver) and relevant risk factors such as travel to or residence in an endemic area.",{"question":136,"answer":137},"\u003Cp>What is the difference between \u003Cem>Entamoeba histolytica\u003C\u002Fem> and \u003Cem>Entamoeba coli\u003C\u002Fem>?\u003C\u002Fp>","\u003Cp>\u003Cem>Entamoeba histolytica\u003C\u002Fem> is the pathogen that causes amoebic dysentery and liver abscess, while \u003Cem>Entamoeba coli\u003C\u002Fem> is a harmless commensal. The most reliable way to tell them apart is the mature cyst. The cyst of \u003Cem>Entamoeba histolytica\u003C\u002Fem> is smaller and has four nuclei, whereas the cyst of \u003Cem>Entamoeba coli\u003C\u002Fem> is larger and has eight nuclei, occasionally up to sixteen. A simple rule is that any \u003Cem>Entamoeba\u003C\u002Fem> cyst with more than four nuclei is \u003Cem>Entamoeba coli\u003C\u002Fem>. Their nuclear detail also differs: \u003Cem>Entamoeba histolytica\u003C\u002Fem> has a small central karyosome with fine even chromatin, while \u003Cem>Entamoeba coli\u003C\u002Fem> has a larger, off-center karyosome with coarse, clumped chromatin.\u003C\u002Fp>",{"question":139,"answer":140},"\u003Cp>What is the infective form of \u003Cem>Entamoeba histolytica\u003C\u002Fem>?\u003C\u002Fp>","\u003Cp>The infective form is the mature quadrinucleate cyst, meaning the cyst that contains four nuclei. It is spherical with a refractile wall and is resistant to the acidic stomach environment, so it passes through the stomach unharmed to reach the intestine. The trophozoite, by contrast, is not infective, because it is destroyed by stomach acid if swallowed and is rapidly killed outside the body.\u003C\u002Fp>",{"question":142,"answer":143},"\u003Cp>Can a liver abscess occur without amoebic dysentery first?\u003C\u002Fp>","\u003Cp>Yes. In roughly half of amoebic liver abscess cases, there is no preceding history of dysentery. The trophozoites can travel from the intestine to the liver through the portal circulation and cause a destructive abscess in a patient who never had bloody diarrhea. For this reason, the absence of a diarrhea history should not lower suspicion for an amoebic liver abscess in someone with right upper quadrant pain, fever, and a tender enlarged liver who has been in an endemic area.\u003C\u002Fp>",[115],{"slug":146,"title":147,"description":148,"seoTitle":42,"seoDescription":42,"author":43,"createdDate":45,"lastUpdatedDate":149,"draft":46,"category":47,"image":42,"faq":150,"tags":169},"cryptosporidium-life-cycle-pathogenesis-lab-diagnosis","Cryptosporidium: Life Cycle, Pathogenesis, Treatment, and Laboratory Diagnosis","\u003Cp>Why does routine stool microscopy miss \u003Cem>Cryptosporidium,\u003C\u002Fem> and why is it so dangerous in HIV\u002FAIDS? Complete \u003Cem>Cryptosporidium parvum\u003C\u002Fem> and \u003Cem>hominis\u003C\u002Fem> life cycle, the autoinfection mechanism, treatment, and the modified acid-fast diagnosis.\u003C\u002Fp>","2026-08-30",[151,154,157,160,163,166],{"question":152,"answer":153},"\u003Cp>Why does a routine stool examination miss \u003Cem>Cryptosporidium\u003C\u002Fem>?\u003C\u002Fp>","\u003Cp>The oocysts are small, about 4 to 6 micrometers, and they do not stand out on a plain wet mount, where they are easily mistaken for yeast. A routine ova and parasite examination is not designed to reveal them. Detection requires a specific method, most commonly a modified acid-fast stain, which shows the oocysts as pink-red spheres, or a fecal antigen test. These have to be specifically requested, which is why the diagnosis is missed when only a routine examination is done.\u003C\u002Fp>",{"question":155,"answer":156},"\u003Cp>Why is \u003Cem>Cryptosporidium\u003C\u002Fem> so dangerous in people with HIV\u002FAIDS?\u003C\u002Fp>","\u003Cp>The severity of cryptosporidiosis depends on the host's immune status, particularly the CD4 count. In a person with normal immunity the infection is controlled and resolves within one to two weeks. In advanced HIV\u002FAIDS with a low CD4 count, the immune system cannot control the parasite, autoinfection continues unchecked, and the diarrhea becomes profuse, persistent, and severe enough to threaten life through fluid and weight loss. The infection can also spread to the biliary tract.\u003C\u002Fp>",{"question":158,"answer":159},"\u003Cp>What is the difference between \u003Cem>Cryptosporidium parvum\u003C\u002Fem> and \u003Cem>Cryptosporidium hominis\u003C\u002Fem>?\u003C\u002Fp>","\u003Cp>Both cause the same disease in humans and look identical under the microscope. \u003Cem>Cryptosporidium parvum\u003C\u002Fem> infects both humans and animals and is therefore zoonotic, while \u003Cem>Cryptosporidium hominis\u003C\u002Fem> is essentially confined to humans. They can be separated only by molecular methods such as PCR. The distinction matters for tracing the source of an outbreak but does not change how an individual patient is treated.\u003C\u002Fp>",{"question":161,"answer":162},"\u003Cp>What does intracellular but extracytoplasmic mean for \u003Cem>Cryptosporidium\u003C\u002Fem>?\u003C\u002Fp>","\u003Cp>After a sporozoite enters an intestinal epithelial cell, it does not move down into the main body of the cell. It stays enclosed by the host cell membrane at the surface of the cell, separated from the cytoplasm. This position is described as intracellular, because it is within the host cell membrane, but extracytoplasmic, because it is not in the cytoplasm. It is an unusual niche and a frequently tested feature.\u003C\u002Fp>",{"question":164,"answer":165},"\u003Cp>How is cryptosporidiosis treated?\u003C\u002Fp>","\u003Cp>Supportive care with rehydration is the foundation for every patient because the diarrhea can cause heavy fluid loss. In a person with normal immunity the infection is self-limiting, and nitazoxanide can shorten it. In a person with HIV\u002FAIDS the most effective treatment is antiretroviral therapy that restores the CD4 count, because the parasite is cleared by the recovering immune system in a way that antiparasitic drugs alone do not achieve.\u003C\u002Fp>",{"question":167,"answer":168},"\u003Cp>Can chlorinating water prevent \u003Cem>Cryptosporidium\u003C\u002Fem>?\u003C\u002Fp>","\u003Cp>Not reliably. The oocyst is resistant to standard chlorine disinfection, which is why the parasite has caused waterborne outbreaks from treated municipal water and swimming pools. Preventing infection depends on filtration and on protecting the water source rather than on chlorination alone. People with weakened immunity are advised to be especially careful with drinking water and to avoid swallowing water while swimming.\u003C\u002Fp>",[115],{"slug":171,"title":172,"description":173,"seoTitle":174,"seoDescription":175,"author":43,"createdDate":176,"lastUpdatedDate":177,"draft":46,"category":47,"image":42,"faq":178,"tags":188},"kato-katz-technique-principle-procedure-results","Kato-Katz Technique: Principle, Procedure, EPG Calculation, and Results","\u003Cp>How to perform the Kato-Katz technique for helminth diagnosis: principle, step-by-step procedure, egg-per-gram (EPG) calculation, WHO infection intensity thresholds, and when to use it over formal-ether concentration.\u003C\u002Fp>","Kato-Katz Technique: Procedure, EPG Calculation, and Interpretation","Perform a Kato-Katz thick smear, identify helminth eggs, calculate eggs per gram, apply infection-intensity thresholds, and recognize method limitations.","2016-05-24","2026-08-22",[179,182,185],{"question":180,"answer":181},"What is the Kato-Katz technique used for?","\u003Cp>The Kato-Katz technique is used for qualitative and quantitative diagnosis of intestinal helminthic infections, specifically soil-transmitted helminths (\u003Cem>Ascaris lumbricoides, Trichuris trichiura\u003C\u002Fem>, hookworm) and \u003Cem>Schistosoma\u003C\u002Fem> species.\u003C\u002Fp>\u003Cp>\u003C\u002Fp>\u003Cp>It presses a standardized volume of stool (41.7 mg) through a mesh screen onto a slide, covers it with glycerol-malachite green cellophane, and allows microscopic identification and counting of helminth eggs. The egg count is multiplied by 24 to give eggs per gram (EPG) of stool, a measure of infection intensity.\u003C\u002Fp>",{"question":183,"answer":184},"Why must Kato-Katz slides for hookworm be read within 30-60 minutes?","\u003Cp>Hookworm eggs have thin shells that are progressively dissolved by the glycerol in the cellophane during the clearing process. After 60 minutes, the shell contents become unrecognizable, and the eggs appear as empty outlines or disappear entirely. \u003C\u002Fp>\u003Cp>\u003C\u002Fp>\u003Cp>\u003Cem>Ascaris, Trichuris,\u003C\u002Fem> and \u003Cem>Schistosoma\u003C\u002Fem> eggs have thicker shells and are stable for up to 24 hours, but hookworm diagnosis requires immediate slide reading.\u003C\u002Fp>",{"question":186,"answer":187},"How is EPG calculated from a Kato-Katz slide?","\u003Cp>EPG (eggs per gram) = number of eggs counted on the slide × 24. The multiplier 24 comes from dividing 1,000 mg (1 gram) by the template volume of 41.7 mg. For example, if you count 50 Ascaris eggs, EPG = 50 × 24 = 1,200 EPG, which classifies as a light infection (WHO threshold: light = 1–4,999 EPG for \u003Cem>Ascaris\u003C\u002Fem>). Always check the kit insert, some templates use slightly different volumes.\u003C\u002Fp>",[69],{"enabled":190,"threads":191,"total":192},true,[],0,[194,200,207,214,220,225,231,236,242,245,252],{"slug":195,"name":43,"description":196,"image":197,"body":198,"postCount":199},"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.*",489,{"slug":201,"name":202,"description":203,"image":204,"body":205,"postCount":206},"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":208,"name":209,"description":210,"image":211,"body":212,"postCount":213},"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":215,"name":216,"description":210,"image":217,"body":218,"postCount":219},"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":221,"name":222,"description":210,"image":42,"body":223,"postCount":224},"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":226,"name":227,"description":228,"image":42,"body":229,"postCount":230},"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":232,"name":233,"description":234,"image":42,"body":42,"postCount":235},"guest-author","Guest Author","Guest Author \u002F Contributor",1,{"slug":237,"name":238,"description":210,"image":239,"body":240,"postCount":241},"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":243,"name":244,"description":234,"image":42,"body":42,"postCount":235},"dr-poonam-acharya","Dr. Poonam Acharya",{"slug":246,"name":247,"description":248,"image":249,"body":250,"postCount":251},"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":253,"name":254,"description":255,"image":256,"body":257,"postCount":235},"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.",[259,266,272,277,282,287,291,295,299,304,308,313,317,322,327,331,335,339,344,349,353,357,361,365,369,373,377,381,386,391,395,399,403,408,412,416,420,424,428,432,436,440,444,448,452,456,460,464,469,473,477,480,484,488,492,496,500,504,508,512,516,520,524,528,532,536,540,544,547,551,554,557,560,563,565,568,571,574,577,580,583,586,589],{"slug":260,"name":261,"description":262,"image":263,"body":264,"postCount":265},"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":267,"name":268,"description":269,"image":42,"body":270,"postCount":271},"microscopy","Microscopy","Microscope types, components, and microscopy techniques","These are list of blog posts related to microscopy. ",12,{"slug":273,"name":274,"description":275,"image":42,"body":42,"postCount":276},"gram-positive-cocci","Gram-Positive Cocci","Staphylococcus, Streptococcus, Enterococcus, Micrococcus — organisms, diseases, and identification tests",11,{"slug":278,"name":279,"description":280,"image":42,"body":42,"postCount":281},"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":283,"name":284,"description":285,"image":42,"body":42,"postCount":286},"gram-positive-rods","Gram-Positive Rods","Bacillus, Clostridium, Listeria, Corynebacterium, Actinomyces and related organisms",8,{"slug":288,"name":289,"description":290,"image":42,"body":42,"postCount":271},"mycobacteria","Mycobacteria","Mycobacterium tuberculosis, leprosy, atypical mycobacteria, and acid-fast organism diagnosis",{"slug":292,"name":293,"description":294,"image":42,"body":42,"postCount":271},"anaerobic-bacteriology","Anaerobic Bacteriology","Anaerobic organisms, anaerobic culture methods, and anaerobic infection diagnosis",{"slug":296,"name":297,"description":298,"image":42,"body":42,"postCount":271},"enterobacteriaceae","Enterobacteriaceae","Identification, differentiation, and clinical significance of Enterobacteriaceae family members",{"slug":300,"name":301,"description":302,"image":42,"body":42,"postCount":303},"spirochetes","Spirochetes","Treponema, Leptospira, Borrelia and spirochetal infections",7,{"slug":305,"name":306,"description":307,"image":42,"body":42,"postCount":265},"food-microbiology","Food Microbiology","Food-borne pathogens, food safety, spoilage, and preservation",{"slug":309,"name":310,"description":311,"image":42,"body":42,"postCount":312},"antimicrobial-susceptibility-testing","Antimicrobial Susceptibility Testing","Methods for testing antibiotic susceptibility in clinical microbiology",21,{"slug":314,"name":315,"description":316,"image":42,"body":42,"postCount":265},"antimicrobials-moa-amr","Antimicrobials (MOA & AMR)","Mechanisms, detection, and clinical significance of antimicrobial resistance",{"slug":318,"name":319,"description":320,"image":42,"body":42,"postCount":321},"sterilization-disinfection","Sterilization and Disinfection","Methods of sterilization and disinfection in healthcare and laboratory settings",10,{"slug":323,"name":324,"description":325,"image":42,"body":42,"postCount":326},"specimen-collection-transport","Specimen Collection and Transport","Collection, handling, and transport of clinical specimens for microbiological testing",27,{"slug":328,"name":329,"description":330,"image":42,"body":42,"postCount":312},"bacterial-structure-physiology","Bacterial Structure and Physiology","Bacterial cell structure, growth, physiology, and environmental factors affecting growth",{"slug":332,"name":333,"description":42,"image":42,"body":334,"postCount":224},"horizontal-gene-transfer","Horizontal Gene Transfer","Articles related to **Horizontal Gene Transfer**",{"slug":336,"name":337,"description":42,"image":42,"body":338,"postCount":321},"chromatography","Chromatography","Information about chromatographic techniques.",{"slug":340,"name":341,"description":342,"image":42,"body":343,"postCount":303},"electrophoresis","Electrophoresis","Information about Electrophoresis Techniques ","Detailed information  about Electrophoresis Techniques ",{"slug":345,"name":346,"description":347,"image":42,"body":348,"postCount":224},"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":350,"name":351,"description":352,"image":42,"body":42,"postCount":224},"bacteriophage","Bacteriophage","Description about Bacteriophage.",{"slug":354,"name":355,"description":356,"image":42,"body":42,"postCount":224},"malaria","Malaria","It is the collections of articles regarding malarial disease. ",{"slug":358,"name":359,"description":360,"image":42,"body":42,"postCount":224},"anaerobic-culture-techniques","Anaerobic Culture Techniques","Posts related with Anaerobic Culture Techniques.",{"slug":362,"name":363,"description":364,"image":42,"body":42,"postCount":219},"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.",{"slug":366,"name":367,"description":368,"image":42,"body":42,"postCount":303},"biosafety-levels","Biosafety levels ","Articles related to Biosafety Levels",{"slug":370,"name":371,"description":372,"image":42,"body":42,"postCount":281},"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":374,"name":375,"description":376,"image":42,"body":42,"postCount":224},"pipette","Pipette","Posts related with Pipette. ",{"slug":378,"name":379,"description":380,"image":42,"body":42,"postCount":303},"bacteriology-mcqs","Bacteriology MCQs","This sections lists MCQs in Bacteriology.",{"slug":382,"name":383,"description":384,"image":42,"body":42,"postCount":385},"parasitology-mcqs","Parasitology MCQs","This section lists MCQs in Parasitology.",2,{"slug":387,"name":388,"description":389,"image":42,"body":42,"postCount":390},"virology-mcqs","Virology MCQs","This is the collections of Multiple Choice Questions in Virology.",4,{"slug":392,"name":393,"description":394,"image":42,"body":42,"postCount":281},"mcqs-in-microbiology","MCQs in Microbiology","This section lists the collections of Multiple Choice Questions in General Microbiology Topics. ",{"slug":396,"name":397,"description":398,"image":42,"body":42,"postCount":303},"immunology-mcqs","Immunology MCQs","In this section; we are posting collections of Multiple Choice Questions about Immunology. ",{"slug":400,"name":401,"description":402,"image":42,"body":42,"postCount":321},"microbial-curiosities","Microbial Curiosities","In this clusters, we are posting interesting and unique information about Microorganisms. ",{"slug":404,"name":405,"description":406,"image":42,"body":42,"postCount":407},"bacterial-culture-media","Bacterial Culture Media","Posts related to Bacterial Culture Media. ",23,{"slug":409,"name":410,"description":411,"image":42,"body":42,"postCount":224},"fungal-culture-media","Fungal Culture Media","Posts related to Fungal Culture Media.",{"slug":413,"name":414,"description":415,"image":42,"body":42,"postCount":281},"motility-test","Motility Test","This lists the procedure regarding various tests methods for bacterial motility.",{"slug":417,"name":418,"description":419,"image":42,"body":42,"postCount":321},"bacterial-enumeration","Bacterial enumeration","These posts are related to isolation and enumeration of bacteria. ",{"slug":421,"name":422,"description":423,"image":42,"body":42,"postCount":385},"gram-positive-coccobacillus","Gram-positive coccobacillus","List of Gram Positive Coccobacilli",{"slug":425,"name":426,"description":427,"image":42,"body":42,"postCount":390},"dimorphic-fungi","Dimorphic Fungi","This is about various dimorphic fungi. ",{"slug":429,"name":430,"description":431,"image":42,"body":42,"postCount":303},"bacterial-classification","Bacterial Classification","These posts are related with various approaches used for the classification of Bacteria. ",{"slug":433,"name":434,"description":435,"image":42,"body":42,"postCount":281},"immunofluorescence","Immunofluorescence ","Various Tests related to Immunofluorescence ",{"slug":437,"name":438,"description":439,"image":42,"body":42,"postCount":230},"antibody-mediated-immunity","Antibody-mediated Immunity","This clusters links the articles that are sharing insights about Antibody-mediated immunity. ",{"slug":441,"name":442,"description":443,"image":42,"body":42,"postCount":303},"hypersensitivity","Hypersensitivity","Articles related to Hypersensitivity.",{"slug":445,"name":446,"description":42,"image":42,"body":42,"postCount":447},"haemophilus","Haemophilus",3,{"slug":449,"name":450,"description":451,"image":42,"body":42,"postCount":390},"sexually-transmitted-infections-stis","Sexually transmitted infections (STIs)","This is the clusters of infections that are transmitted sexually. ",{"slug":453,"name":454,"description":455,"image":42,"body":42,"postCount":271},"adaptive-immunity","Adaptive Immunity","Blog posts related to B Cell Immunity and T Cell Immunity.",{"slug":457,"name":458,"description":459,"image":42,"body":42,"postCount":265},"fungal-diagnostics","Fungal Diagnostics","Various methods used for the Diagnosis of Fungal Infections. ",{"slug":461,"name":462,"description":463,"image":42,"body":42,"postCount":281},"laboratory-storage-and-preservation","Laboratory Storage and Preservation","Articles about Laboratory Storage of Antimicrobial Disk, Test organisms and Equipment used for this process. ",{"slug":465,"name":466,"description":467,"image":42,"body":468,"postCount":224},"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":470,"name":471,"description":472,"image":42,"body":42,"postCount":230},"laboratory-glassware","Laboratory Glassware","Posts about Laboratory Glassware. ",{"slug":474,"name":475,"description":476,"image":42,"body":42,"postCount":230},"helminths","Helminths","In this section, we are covering properties, life cycle, pathogenesis and laboratory diagnosis of Helminths\u002FHelminthic infestations. ",{"slug":115,"name":478,"description":479,"image":42,"body":42,"postCount":286},"Protozoan Parasite","In this cluster, we are covering protozoan parasites. ",{"slug":481,"name":482,"description":483,"image":42,"body":42,"postCount":235},"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":485,"name":486,"description":487,"image":42,"body":42,"postCount":321},"bacterial-staining-technique","Bacterial Staining Technique","Lists of various staining techniques that are used to stain bacteria. ",{"slug":489,"name":490,"description":491,"image":42,"body":42,"postCount":312},"enzyme-tests","Enzyme Tests","\u003Cp>Various Biochemical Test that are based on enzymatic activity of the microorganisms. \u003C\u002Fp>",{"slug":493,"name":494,"description":495,"image":42,"body":42,"postCount":276},"carbohydrate-utilization","Carbohydrate Utilization","\u003Cp>Various biochemical tests which are related to Carbohydrate fermentation or Utilization\u003C\u002Fp>",{"slug":497,"name":498,"description":499,"image":42,"body":42,"postCount":281},"susceptibility-based-id","Susceptibility-based ID","\u003Cp>These are susceptibility based identification test such as optochin sensitivity, bacitracin sensitivity etc. \u003C\u002Fp>",{"slug":501,"name":502,"description":503,"image":42,"body":42,"postCount":390},"microbial-metabolism","Microbial Metabolism","\u003Cp>Tests about Microbial Metabolism. \u003C\u002Fp>",{"slug":505,"name":506,"description":507,"image":42,"body":42,"postCount":286},"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":509,"name":510,"description":511,"image":42,"body":42,"postCount":447},"atypical-pneumonia","Atypical Pneumonia","\u003Cp>Organisms responsible for Atypical Pneumonia. \u003C\u002Fp>",{"slug":513,"name":514,"description":515,"image":42,"body":42,"postCount":281},"antigen","Antigen","\u003Cp>Various articles related to Antigens.\u003C\u002Fp>",{"slug":517,"name":518,"description":519,"image":42,"body":42,"postCount":303},"innate-immunity","Innate Immunity","\u003Cp>Articles related to Innate Immunity. \u003C\u002Fp>",{"slug":521,"name":522,"description":523,"image":42,"body":42,"postCount":390},"respiratory-tract-infection","Respiratory Tract Infection","\u003Cp>In this cluster, you can see various etiological agents that causes respiratory tract infection. \u003C\u002Fp>",{"slug":525,"name":526,"description":527,"image":42,"body":42,"postCount":281},"torch-infection","TORCH Infection","\u003Cp>In this section; you can find articles related with TOCH infection. \u003C\u002Fp>",{"slug":529,"name":530,"description":531,"image":42,"body":42,"postCount":286},"microbiology-for-beginners","Microbiology for Beginners","\u003Cp>These articles are very basic articles, which will share general concepts in Microbiology. \u003C\u002Fp>",{"slug":533,"name":534,"description":535,"image":42,"body":42,"postCount":224},"dna-replication","DNA Replication","\u003Cp>Articles related to DNA and Replication of DNA. \u003C\u002Fp>",{"slug":537,"name":538,"description":539,"image":42,"body":42,"postCount":303},"genetic-code","Genetic Code","\u003Cp>Articles related to Genetic Code.\u003C\u002Fp>",{"slug":541,"name":542,"description":543,"image":42,"body":42,"postCount":303},"molecular-technique","Molecular Technique","\u003Cp>Posts related to Molecular Techniques. \u003C\u002Fp>",{"slug":545,"name":546,"description":42,"image":42,"body":42,"postCount":235},"colorimetric-assay","Colorimetric Assay ",{"slug":548,"name":549,"description":550,"image":42,"body":42,"postCount":281},"pharmaceutical-microbiology","Pharmaceutical Microbiology","\u003Cp>Various articles related to Pharmaceutical Microbiology\u003C\u002Fp>",{"slug":552,"name":553,"description":42,"image":42,"body":42,"postCount":447},"blood-and-immune-cells","Blood and Immune Cells",{"slug":555,"name":556,"description":42,"image":42,"body":42,"postCount":281},"host-pathogen-interaction","Host Pathogen Interaction",{"slug":558,"name":559,"description":42,"image":42,"body":42,"postCount":390},"blood-culture","Blood Culture",{"slug":561,"name":562,"description":42,"image":42,"body":42,"postCount":390},"environmental-microbiology","Environmental microbiology ",{"slug":69,"name":564,"description":42,"image":42,"body":42,"postCount":303},"Copromicroscopic Technique",{"slug":566,"name":567,"description":42,"image":42,"body":42,"postCount":447},"quality-control","Quality Control",{"slug":569,"name":570,"description":42,"image":42,"body":42,"postCount":303},"dermatophytes","Dermatophytes",{"slug":572,"name":573,"description":42,"image":42,"body":42,"postCount":447},"viral-hemorrhagic-fevers","Viral Hemorrhagic Fevers",{"slug":575,"name":576,"description":42,"image":42,"body":42,"postCount":390},"h2s-production","H2S Production",{"slug":578,"name":579,"description":42,"image":42,"body":42,"postCount":385},"water-quality-testing","Water Quality Testing",{"slug":581,"name":582,"description":42,"image":42,"body":42,"postCount":281},"virology-basics","Virology basics",{"slug":584,"name":585,"description":42,"image":42,"body":42,"postCount":390},"typing-methods","Typing Methods",{"slug":587,"name":588,"description":42,"image":42,"body":42,"postCount":447},"blotting-technique","Blotting Technique",{"slug":590,"name":591,"description":42,"image":42,"body":42,"postCount":390},"history-microbiology","History of Microbiology"]