MICROBIOLOGY LABORATORY REPORTCOMPILED ON: 13/02/2013DUE DATE: 19 /02/2013BY;KEMO KEBAITSANG
ID;3005LECTURER; MR MOLEFHI |
Identification of entrobacteriaceae | Escherichia coli cause 99% of URINARY TRACT INFECTION. |
DAY 2
GRAM STAINNING
Materials
* Two slides * Saline water * Culture organisms * Wire loop * Gentin violet * Iodine * Safradin * 95% alcohol
Procedure
* Prepare slide smears of both cultured organisms and heat fix them. * Gram stain with first using Gentin violet as primary stain then, * Iodine as a mordent and decolourise with 95% alcohol, finally use * Safradin as a counter stain. * Observe the slides under microscope and record results.
BIOCHEMICAL TESTS
SUSCEPTIVITY TESTING
Materials
* MHA agar * Organism grown in Broth * Swabbing stick *
Principle
Procedure
TSI (TRIPLE SUGAR IRON TEST)
Materials
* TSI agar * Straight wire loop * Cultured colony of organism * Purity plate
Principle
TSI agar detects fermentation of glucose 0.1%, lactose 1% and sucrose 1%, production of H2S, and gas formation. The medium contains ferric ammonium citrate, and phenol red indicator
Procedure
* Take half of an isolated colony and stab the butt of the agar and make streaks on the slant. * Close the agar using a cotton wool plug. * Take the other half of the organism and make a purity plate, incubate the two agars at 37o C over night.
Expected results When there is sugar fermentation in both butt and slant the agar is yellow showing production of acid. H2S reacts with ferric ammonium citrate to form a black product called ferrous sulphide, and gas production is seen by cracks or bubbles forming in the agar. This observation is evident only when the organism tests positive.
CITRATE TEST
Materials
* Citrate agar slant * Inoculating loop * Culture colony
Principle
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