QUESTIONS Acid-Fast Staining What are the large blue-stained areas on the apatum
ID: 147581 • Letter: Q
Question
QUESTIONS Acid-Fast Staining What are the large blue-stained areas on the apatum What is the decolorizing ngent in the Grum stain? In the acid-fast stain? What diseases are dingnosed ares on the spatum slide White blood ceis using the acid-aat procedure? : What is phenol (earbolie acidi, and what is its usual application? AR Omatic componna 3 iS ivte of benzene Manly wua as disentea. Carbolfuchsin used in the original acid-faat stain nol, and 95 ml water consiste of 0.3 g bane fuch in in 10 ml 95% ethanol 5 ml phe recipe for the Kinyoun modification is 4 g basic fuchain in 20 ml ethanol, 5 g phenol, water. ycae original neid-fast stain required heating the smear to force the carbolfuchsin into that you used? CRITICAL THINKING How might the acid-fast characteristic of Myeobacterium enhance the organism's ability to cause tf o perjon is SicK Maxiny chances uf disease move ivey would be effective against Myeobacterium. How did he reach this conclusion without testing the disinfectan In 1882, after experimenting with staining Mycobacterium, Paul Ehrlich wrote that only alkaline disinfectants LINICAL APPLICATIONS inical specimens suspected of containing Mcobacterium are digested with sodium bydroxide (NaOH) for 30 minutes prior to staining. Why is this technique used? Why isn't this technique used for staining other bacteria? The acid-fast stain is used to deteet Cryptosporidium protozoa oocysta in fecal samples. Which of the following would you expect to be a major component of the oocyst wall: carbohydrates,lipids,or proteins? What disease is caused by Cryptosporidium? In 1993, Milwaukee experienced the largest outbreak of Cryptosporidium in the United States. The parasite infected a half million people through their drinking water. How could this parasite get into drinking water?Explanation / Answer
1)Decolourizing agent in gram stain is ethyl alcohol or acetone. It dissolves the lipids of Gram negative bacteria's outer membrane and allows the leakage of primary stain crystal violet and iodine complex out of the thin peptidoglycan layer.Gram positve bacteria have thicker peptidoglycan which resist decolourization as it closes pores due to dehydration by alchol/acetone.
2) In acid fast stain decolourizing agent is acid alcohol (Hcl and ethanol). Mycobacterial cell wall is lipid rich mainly mycolic acid. This prevent the easy penetration of dyes into the cell. Heat and phenol are used to move the dye basic fuchsin inside the cells. These cells are not decolourized by acid-alchol because of the lipid rich cell wall. Thus the bacteria are called acid fast.Therefore only Mycobacterium is stained and all other cells are easily destained.
3)It is used to diagnose tuberculosis caused by Mycobacterium tuberculosis
4)In the kinyoun staining procedure the heating step can be eliminated as the amount of stain carbol fushin is increased from 0.3 to 4 grams. Phenol concentration is also increased which helps in penetration of dye.
5) The Mycobacterial cell wall is lipid rich particularly mycolic acid and and would be resistant to acidic disinfectants. Alkaline disinfectant with high pH would be able to attack the pathogen wall. The bacterium is acid fast i.e acid is unable to penetrate and decolourize cells. Therefore any acidic disinfectant would be repelled by the mycolic acid rich cell wall.
6)Clinical specimen for tuberculosis detection consist of sputum sample for identification of Mycobacteria via staining. The sputum contains mucoid material and other bacteria which are part of the normal microflora of human body. Mycobacterium is a slow growing organism and other contaminating bacteria in the sample can overgrow in culture plates. Therefore decontamination of the sputum is essential for growth of Mycobacteria. NaOH serves the purpose of sputum decontaminant. It digests mucus material and contaminating microflora.
7) The major component of oocyst wall is expected to be lipids as in acid-fast bacteria like Mycobacterium.
8) Crytosporidium causes Cryptosporidiosis which is a gastrointestinal and respiratory tract disease.
9) Cryptosporidium is found in the intestines of birds and animals. Water contaminated with the feces of these birds and animals contains oocyst of the pathogen. The size of oocyst is very small (4 -6 um) to be filtered by normal sand filters used for drinking water purification.