Posts Tagged ‘gram’s staining’

Identification of Neisseria gonorrhea

Posted 03 Mar 2010 — by admin
Category Laboratory Procedures, Microbiology

Neisseria gonorrhea is the causative agent of gonorrhea a sexually transmitted disease (STD). They are coffee-bean shaped cocci occurring in pairs. They are gram-negative, intracellular diplococci and they are stained using gram staining.

Identification of Neisseria gonorrhea is easy with a simple smear.

Materials needed

Clean and dry glass slide

Applicator stick with cotton

Grams stain

Personal protective equipment

Procedure

Step 1

Wear your personal protective equipment (PPE), gloves, masks and laboratory gown. Neisseria gonorrhea could infect the eyes and your throat. They could cause gonorrheal blindness and throat infections if not diagnosed immediately.

Step 2

With an applicator stick, collect the specimen from the cervical or vaginal area. Sometimes the doctor collects the specimen during his examination.

Step 3

Make a smear of the secretion on the clean and dry glass slide, not too thick or too thin. Identification of Neisseria gonorrhea is facilitated when the simple smear is properly prepared.

Step 4

Allow to air dry or through exposure to direct flame. This will allow the smear to stick to the slide and not washed off during staining.

Step 5

Place in a staining rack and add crystal violet until all the smear is exposed to the stain. The time will depend upon the staining kit’s instructions. The time varies with newly developed kits.

Step 6

Wash the slide and add acid alcohol to decolorize. The gram-positive bacteria will take up the crystal violet while the gram-negative bacteria like Neisseria gonorrhea will decolorize.

Step 7

Wash with distilled water and add safranin. The gram-negative bacteria will take up this stain and will be colored pink. While the gram positive bacteria will be stained purple or violet, taking up the color of crystal violet.

Step 8

Wash again with distilled water and allow to dry.

Step 9

Focus in the microscope using the low power objective (LPO), then shift to the high power objective (HPO) or shift straight to the oil immersion objective (OIO). When using the OIO, place a drop of oil into the slide to be able to see clearly.

Step 10

Following a four field meander, scan the slide for the presence of gram-negative intracellular, diplococci. You should scan the whole slide, as you may not see them immediately. A large amount of pus cells is usually one indication of the infection. Do not report however as positive unless you have observed the diploccoci in the smear itself. Step 10 Record and report your findings.

Step 11

Dispose of your materials properly.