Page 82 - MNUmicrobiology practical 2025
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General Microbiology & Immunology (PM 401)    second level    Semester 4       2024/2025


                  3- Clean microscope slides


                  4- Modified Ziehl Neelsen staining reagents


                  - Carbol fuchsin [primary stain]


                  - (0.25%  -0.5 %H2so4)[ Decolorizing agent]

                  -Methylene blue [counterstain]

                  5- Inoculating loop

                  6-Bunsen burner

                  7- Slide holder.

                  8- Staining rack

                  10- Washing water

                  10- Microscope with oil immersion lens

                  12- Marker pen




                  Modified Ziehl Neelsen staining steps


                 1-  Prepare of bacterial smear


                 2-  Flood the smear with the primary stain (carbol

                     fuchsin), place it in a boiling water bath over

                     hot plate, and let it sit for 5 minutes (gentle

                     heat or steam act as a mordant as it helps in

                     penetration and retention of dye)


                 3-  Reapplying stain if it begins to dry out


                 4-  Let the glass slide cool and wash the smear with slow-running water


                      5-  Decolorize with 6 drops of (0.25% -0.5 %H2so4) for 10 – 15 seconds, then
                         rinse with water.

                  General Microbiology & Immunology (PM 401)   Practical note                         Page 71
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