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Staining Techniques use in microbiology. Obj ect ive. To examine the morphology To classify and identify To examine the different structure. Preparation of bacterial culture smear. Place a drop of water on a clean glass slide. Take loopful culture Allow the smear air dry
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Staining Techniques use in microbiology
Objective • To examine the morphology • To classify and identify • To examine the different structure
Preparation ofbacterialculture smear • Place a drop of water on a clean glass slide. • Take loopful culture • Allow the smear air dry • Fix the smear by passing on the flame
Types ofstainingmethods A.Simple staining methods B.Differential staining methods C. Special staining method
A. Simplestainingmethods: • only one dye is used • Use: to study the morphology as well as to presence or absence of bacteria in smear
Methylenebluemethod • Procedure: Pour the stain solution on smear allow to act for 1 minute Rinse with water blot and examine under the oil immersion lens Result • Bacteria appear blue in colour
Leishman’s method Procedure: • Pour the stain over the smear and allow for 1 min • Pour double quantity of buffered distilled water and allow for 10 minute. • Wash the smear with distilled water, blot & examine Result Organism appear blue in colour Use: HS and Anthrax organisms are stain by this method
Negativestainingmethod Instead of staining the bacteria only their background is stained. Method • Mix loopful of the culture with equal quantity of stain on the slide and prepare a thin, uniform smear. • Allow it to air dry and examine. Result • The bacteria appear colorless.
B. Differentialstainingmethods. • useful in identification • Useful in classification • more than one dye is used.
Gram’sstainingmethod Procedure • smear fix over flame. • crystal violet stain --- for 2 minutes • Wash with tap water • Gram’s iodine for 1 minute • Wash with tap water • acetone -----------------2-3 second • Wash with tap water • Safranin ----------------1 minute • Wash with water blot and examine.
Result Gram positive bacteria will appear violet in colour Gram negative bacteria will appear pink in colour
Acid-Faststaining Procedure • Prepare the bacterial smear and fix over the flame. • ZN Carbon fuschsin ------- heat--- 10 min Wash with water. • Acid alcohol ---------------------------- 20 seconds • malachite green ---------- 1 minute • Wash with water
Result Acid fast bacteria stain bright red colour Non acid fast bacteria and tissue cell stain green Use : to stain culture smear of tuberculosis and John’s disease.
ModifiedZ-N stain Procedure: • Fix the smear in methanol. • carbol fuchsin ---------- 10 minute • Wash with water • acetic acid ---------------- 30seconds • Wash with water • methylene blue ---------- 20 seconds
Result Organism take red color. Back ground take blue color. Use: For staining the organism likeBrucella abortus, Coxiella burneti, Chlamidia psittaci
MACCHIAVELLOSTAIN Procedure : • Prepare a thin smear of yolk sac tissue free of yolk fluid , air dry fix with heat, • cover with 0.25% aqueous basic fuschin for 5 minutes and drain, • Cover with 0.5%citric acid solution and wash immediately, • Counter stain with 1% aqueous methylene blue for 20-40 seconds, rinse and dry. Use : to stain Rickettsia
Result : • Rickettsia will be stain bright red • Back ground will be blue • Most of bacteria stain blue but some retain the red color.
Otherstainsused GABBETTS STAIN METHOD for acid fast organism KOSTER STAIN for Brucella organism BARBEITO-LEPEZ TRICHROME STAIN for connective tissue
C.Specialstaining methods • This staining methods are used to demonstrate the presence of certain bacterial structure like spores, capsules, flagella and metachromatic granules.
Schaeffer &Fulton'smethod spore staining Procedure • make bacterial smear and fix over flame. • Pour Malachite green and heat the slide to steaming for 5 minutes. • Allow to cool it for 5 minutes. • Wash with water. • Apply counter stain Saffranin 1 minute. • Wash with water, blot and examine.
Use: for identification of spore forming organism like Bacillus and clostridium genera. Result • Spores will appear green while vegetative cell will stainred.
Capsulestain • Use: for identification of capsularorganism like klebsiella,pneumococci, B. anthracis etc.
Loeffler’s alkaline methylene blue(LAMB) method Use: To demonstrate the capsulated Anthrax bacilli in blood smear. Procedure Fix the smear with alcohol. Pour LAMB stain and allow for 2-3 minute. Wash with water, blot and examine.
Result Capsule will be stained pink while the bacilli blue in colour
FlagellastainLeifson method Use : to examine the flagella organism • Procedure • wash the cell twice by centrifuging. • suspend the cells and incubate for 10 minute at 37 0C. • Mark area of about 1 x 1.5 sq. inch on clean glass slide, • place loopful of the washed bacterial suspension,dry in air. • Apply stain till there is formation of the precipitate in the stain. • Remove stain with gentle stream of water. • Counter stain with methylene blue for 1 minute. • Wash with water, air dry and examine.
Result • Flagella will appeared as thread like pink to red stain.
staining inclusion bodies • Phloxine-tartrazine stain • Neisser stain for metachromatic granules
Stain use forfungusLacto phenolcottonblue stain Method -Place a drop of stain on slide and in this gently tease small portion of culture using a mounting needle. -Place a No 1 cover slip on top avoiding formation of air bubble and remove excess stain around the edges of the cover slip. -Examine under microscope.
StainsUse forVirusAcridine Orange • Procedure: Wash cover slip cultures in three changes of phosphate buffer saline • Fix in carnoy’s fixative for 1-2 minuts. • 95%, 70%, 50%, 30% ethyl alcohol 2 min respectively • Rinse in de-ionized water • Stain in Acridine orange solution for 5 min • Rinse with buffer for 5 min • Mount • Examine under U.V Microscope • Result – DNA fluoresces yellow • RNA fluoresces Flame red.
Feulginstain Producer: Wash cover slip cultures in three changes of phosphate buffer saline Fix in carnoy’s fixative for 20 ml • 90%, 70%, ethyl alcohol for 2 min respectively, • Wash under tap-water for 2 min • 0.1 N HCL for 2 min • Transfer to 0.1 N HCL, pre-warmed to 600C for 10-20 min • 0.1 N HCL at room temperature for 2 min • Wash quickly in tap water • Transfer to schiff reagent for 30 min. • Wash in running water for 15 min. • Counter stain with 0.5% light green if desited, and wash in tap-water. • Dehydrate rapidly in 70% ethyl alcohol • Two rapid changes in 95% ethyl alcohol • Two rapid changes in 100% ethyl alcohol • Clean in xylol • Mount
Result • Nuclei and DNA containing material stain a reddish purple colour
Sellerstain Use: Excellent stain for demonstrating the cytoplasmic inclusions (Negri bodies) associated with rabies virus infection. Procedure: -Prepare impression smear immediately immerse it in the stain for 1-5 sec. -Rinse quickly in running water. -Drain and dry in air, without blotting. -Mount
Result • Negribody stain magenta and appear heterogeneous in structure.