Medical Microbiology Lab 2 PDF

Medical Microbiology Laboratory Bacterial staining University Of Fallujah College Of Medicine Lecture : Lab. 2. Stage : Third stage Lecturer : Assistant Teacher Fairooz Bahr Sultan Department: Microbiology Date: 1/10/2024, Tuesday Medical Microbiology...

Medical Microbiology Laboratory Bacterial staining University Of Fallujah College Of Medicine Lecture : Lab. 2. Stage : Third stage Lecturer : Assistant Teacher Fairooz Bahr Sultan Department: Microbiology Date: 1/10/2024, Tuesday Medical Microbiology Laboratory Lab 2 Bacterial Staining Gram stain One of the most important biological staining processes in B microbiology. Differential stain. Used to separate all bacteria in to 2 groups. Dependent upon the construction of the bacteria's cell wall. B Preparation of bacterial specimens:  The Bbacteria must be place on a glass slide and prepared for the specific staining process.  Preparing a bacterial smear which is a small volume (aloopful) of specimen that is spread (smeared) on to a microscope slide.  Following preparation of a bacterial smear, most smears need to be heat fixed before they are stain. Preparation of bacterial specimens:  Heat fixation accomplishes three things: (1) it kills the B organisms; (2) it causes the organisms to adhere to the slide; and (3) it alters the organisms so that they more readily accept stains (dyes)  Slides must be completely dry before heat-fixing, or the organism will be boiled and destroyed. If you heat-fix too little, the organism will wash off the slide.  If you heat-fix too much, the organisms may be incinerated. The Gram Stain Procedure Preparation B of Smear (is to fix the bacteria onto the slide and to prevent the sample from being lost during a staining procedure). Crystal violet–1min–wash. Iodine–1min–wash. Acetone-across the slide about 5 sec. Safranine-1min–wash. Not: Results should be confirmed only with100X. Result: B Colour:  Purple colored bacteria–gram positive.  Pink colored bacteria–gram negative. Arrangement:  Cocci in clusters Staphylococci.  Cocci in chains Streptococci. Gram positive cocci in clusters (Staphylococcus B aureus) Gram positive cocci in chains (Streptococcus pyogenes) Gram negative bacilli (Escherichia B coli) Gram positive bacilli (Lactobacillus) Gram negative cocci (Neisseria B conorrhoeae) B