Blastocystis hominis and e. polecki


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  • This is not surprising given the economy and culture of this country where pigs play a key role and many pigs are even allowed to live in residences.
  • Mononucleated wherein nucleus is about 1/3 of the cysts diameter
  • All antiamebic drugs was used without success, but w/ the used of metronidazole was proved it’seffectiveness alone without the accompanying the diloxanidefuroate.
  • These pseudopodia are the means by which these organisms move and engulf bacteria and red blood cells for feeding purposes.
  • The precise transmission mechanisms of BlastocystisHominis remain murky.  Fecal-oral transmission is the most accepted pathway, and recent studies have shown that transmission involves only the cyst form (infective stage)of the parasite.[9]  The extent to which human-human, human-animal, and animal-human transmission occurs is still unknown, Conclusively stating that BlastocysistisHominis has an animal reservoir depends upon unraveling the true nature of its transmission.  If, as Noël et al. deem likely based upon their own molecular work and a review of the literature, animal-to-human transmission is possible, then animals such as pigs and dogs could in fact be acting as a large reservoir capable of human infection
  • 2nd bullet-(e.g., lakes, streams, shallow [less than 50 feet] or poorly monitored or maintained wells).3rd bullet-Recreational water includes water in swimming pools, water parks, hot tubs or spas, fountains, lakes, rivers, springs, ponds, or streams that can be contaminated with feces or sewage from humans or animals.Eating uncooked food contaminated with
  • Protected by outer shell thus can survive outside host-environment
  • Study byUdkow and Markell show that same number of stool examination of both a/symptomatic essentially has same prevalenceNo evidence that plays an important role to immunosuppressed persons.
  • Being stramenophiles is because of formerly characterization of being a non-pathogenic yeast
  • The CDC recommends that samples be concentrated and at least three separate samples should be taken before a negative result is confirmed.  The two most common methods for preparing slides are a wet mount and a trichrome stain.  In the wet mount BlastocystisHominis is stained with iodine and appears as a large vacuole in the middle of many small nuclei, though it may be difficult to see.  In the trichrome stain, the parasite is stained with trichrome giving the large central body a gray or green appearance and the cytoplasm elements a dark red color
  • Chemotherapeutic drug Metronidazole- while effective in some individuals, shows signs of resistance by B. hominis or limited effectiveness in others
  • Blastocystis hominis and e. polecki

    1. 1. • Entamoeba Polecki was first identified in 1912 in Czechoslovakia by Von Prowazek in the stool samples of two students from Kampuchea. • E. Polecki was repeatedly found in pig feces, but no other human cases were reported until 1949 • Maybe asymptomatic or mistaken as E. histolytica
    2. 2. Intestinal parasite of pigs and monkeys Found occasionally in human Common intestinal parasite in parts of Papua New Guinea (19%) Pig-to-human transmission Human-to-human transmission
    3. 3. • Cyst and trophozoite • Cyst’s usual size, 5-11 µm • Trophozoites’ usual size, 10-12 µm which is usually round
    4. 4. • Almost all of entamoeba spp are morphologically identical and of the size range, BUT CAN BE DIFFIRENTIATED BY isoenzyme analysis, restriction fragment length polymorphism and typing with monoclonal antibodies.
    5. 5. • KNOWN AS NON- PATHOGENIC • Diarrhea • Isoenzyme studies of a number of isolates- E. polecki vs E. dispar • Isoenzyme characterization (trophozoites)-E. polecki vs. E. chattoni
    6. 6. Stage & preparation Characteristics Trophozoites, unstained Not characteristic Trophozoites, stained Suggestive: nucleus with minute central karyosome, w/ peripheral chromatin evenly distributed or massed at one or both poles; ingested bacteria Cysts, unstained Suggestive: uniform mononuclear condition Cysts, stained (iodine) Suggestive: mononucleated cysts; large central karyosomes w/ evenly distributed peripheral chromatin or massed at one or both poles Diagnostic: inclusion masses, chromatoidal bars w/ angular or pointed ends.
    7. 7. Cyst of E. polecki in a wet mount Stained with iodine. Notice the numerous chromatoid bodies (arrows).
    8. 8. Cysts of E. polecki stained with trichrome. Notice the large nucleus with a pleomorphic karyosome and numerous variably-shaped chromatoid bodies.
    9. 9. Trophozoites of E. polecki stained with trichrome The single nucleus is often distorted and irregularly-shaped, with a small to minute centrally-located karyosome. Peripheral chromatin is usually delicate and uniform. The cytoplasm is often vacuolated with a hyaline border. Blunt pseudopodia may be seen.
    10. 10. • Except diloxanide furoate (Furamide) and metronidazole (Flagyl) • Pilot by Salaki and coworkers (1979) • 750mg 3x/ daily for 10 days with 500mg 3x/ daily for 10 days • 750mg 3x/ daily for 5,7, or 10 days
    11. 11. • Kingdom: Protista • Subkingdom: Protozoa • Phylum: Sarcomastigophora • Subphylum: Sarcodina • Superclass: Rhizopoda • Class: Lobosea • Subclass: Gymnamoeba • Order: Amoebida • Suborder: Blastocystina • Genus: Blastocystis • Species: Hominis
    12. 12. • Pseudoparasite hence non -pathogenic • Generally consider a nonpathogenic yeast in the past • Some maintain that it has protozoan affinities, although on the basis of rRNA sequencing, its phylogenetic affinities are less clear (Johnsons et al., 1989) • Inhabitant of the human intestinal tract • Binary fission • Having pseudopod extension and retraction
    13. 13. • Accidentally swallowing Blastocystis 'hominis' picked up from surfaces contaminated with feces from an infected person or animal. • Drinking water or using ice made from contaminated sources • Swallowing recreational water contaminated with Blastocystis 'hominis'. • Traveling to countries where Blastocystosis is common and being exposed to the parasite as described in the bullets above.
    14. 14. • The classic form that is usually seen in stool specimens varies in size from 6 - 40mm and is characterized by a large membrane bound central body which occupies 90% of the cell. It has no internal nuclear structure and a rim of peripheral granules the function of which is not known.
    15. 15. • Generally when seen in stool, we do not give significance BUT the pathogenic potential of Blastocystis may very well depend on subtype. • 95% of humans colonized by Blastocystis have one of the following subtypes: ST1, ST2, ST3, ST4 hence acknowledge as pathogen • Organism has been associated with nausea, fever, vomiting, diarrhea and abdominal pain.
    16. 16. • Found a DNA-based home w/ highly diverse protistan group-the stramenophiles (a vast array of organisms including brown algae, water molds, and diatom) • Found in the immunocompetent persons but commonly in patients with GIT disorders
    17. 17. Type of preparation Characterization Iodine preparations The peripheral layer is light yellowish and the nuclei position is clearly indicated Permanent stains Central material has intense stain, stain lightly or may not stain at all; the nuclei is dark, and embedded PCR and culture use/Fields’ and Giemsa Accurate diagnosis is warranted if this was the first choice
    18. 18. Iodine stained
    19. 19. Trichome stained
    20. 20. Romanowski’s stain Cyst of Blastocystis hominis demonstrating its vacuolated cell wall.
    21. 21. Giemsa stained Cyst-forming microbes of varying sizes observed in the feces
    22. 22. Papanicolaou stained Cyst-forming microbes of varying sizes observed in the feces
    23. 23. • Several said that it is still unidentified. • no single drug or no particular diet appears to be capable of eradicating Blastocystis • Chemotherapeutic drug Metronidazole- most widely used treatment option • Nitazoxanide- recent study, has been with much more positive effects, with 86% of those treated with the drug effectively cured