Tag: #lab

GOOD LABORATORY PRACTICES AND BIO-SAFETY METHODS

  1. When you arrive the laboratory, the first thing is that you must wash your hands with a disinfectant soap for your immediate sanitization.
  2. Eating anything in the laboratory area and smoking is strictly prohibited. Do not put anything in your mouth such as pencils, labels, or fingers. Do not store food in areas where microorganisms are stored.
  3. Purchase a lab coat and safety glasses and use them. Leave protective clothing in lab and do not wear it in non-lab areas.
Photo by Chokniti Khongchum on Pexels.com
  1. Avoid loose fitting items of clothing. Wear appropriate shoes (sandals not allowed) in the laboratory.
  2. Backpacks, purses and quotes should be placed in the cubbyhole by the front door of the lab. Place needed items on the floor near your feet, but not in the aisle.
  3. Disinfect work areas before and after use with 70% ethanol and fresh 10% bleach. The regular disinfection of the laboratory surfaces must be done using appropriate disinfectants like hypochlorite solution which kills almost pathogenic microorganisms.
  4. Label everything clearly.
  5. Caps and lids of reagents, solution bottles, and bacterial must be replaced properly in order to prevent contamination and petri dishes must not be opened directly in the lab unless absolutely necessary.
  6. Inoculating loops and needles should be flame sterilize in a bunsen burner before you lay them down.
  7. Turn of bunsen burner when not in use. Long hair must be restrained if bunsen burner are in use.
  8. Flame sterilization using alcohol must be done so carefully and it must be kept in mind that no papers or similar materials that can catch fire easily are nearby.
  9. Treat all microorganisms as potential pathogens and culturing of microorganisms must be done inside a special sterilized laminar flow hood and not outside it because many air-borne microorganisms can be spread.
  10. Wear disposable gloves when working with potentially infectious microbes and samples. If you are surely working with a pathogenic sample, you must handle it with extra care so that it doesn’t spill out on you or on any surface of the laboratory.
  11. Sterilize equipment and materials.
  12. Never pipette by mouth.
  13. Consider everything a bio hazard. Do not pour anything down the sink. Autoclave liquids and brought cultures to sterilize them before discarding.
  14. Dispose off all solid waste material in a biohazard bag and autoclave it before discarding in the regular trash.
  15. There are a special column of safety equipment in the laboratory which you must be aware of so that in case of any emergency you can make use of those safety equipments.
  16. Dispose of broken glass in the broken glass container.
  17. Dispose of razor blades, syringes, and sharp metal object in the “sharps” container.
  18. If by any chance, there is any type of spill of sample or culture or any media, you must immediately contact your instructor or mentor so that he/she can help you and find a solution to remove it from the surface. If you’re able to clean the spill by yourself do it immediately.
  19. In the same way, in case of any mishappening or sudden accident, you must immediately report to your instructor for the immediate help.

BASICS OF A MICROBIOLOGY LAB

Microbiology is the study of microbes i.e. the organisms which we can’t see with the naked eyes. Although many microorganisms are beneficial for the human use, some are pathogenic also which causes diseases. Clinical Microbiological Laboratory is concerned with finding of those infectious, pathogenic microbes.

MATERIALS USED IN MICROBIOLOGY LAB
Laminar flow hood, Incubator, Autoclave, Refrigerator, Bunsen Burner, Wire loop, Petri plates, Glass slides, Weighing balance, Media plates, Sensitivity disks, Staining rack, Microscope, Bio safety Cabinet, Centrifuge etc.

INTRODUCTION TO DIFFERENT MEDIA
Some of the media used in the microbiology lab are :

  1. MacCONKEY AGAR : It is the selective and differential media used for the isolation of Gram-negative Bacteria. This media can be used for differentiating Lactose fermenting and Non-lactose fermenting bacteria.
  2. BLOOD AGAR : It is the enriched media for the growth of bacteria such as streptococci.
  3. CHOCOLATE AGAR : It is the lysed Blood Agar. The only difference in blood agar and chocolate agar is that in blood agar RBCs are lysed. This enriched media is suitable for the growth of bacteria that are unable to grow on Blood Agar.
  4. THIOSULFATE CITRATE BILE SALT AGAR (TCBS) : It is the selective as well as differential media for the growth of vibrio cholerae , a causative organism for cholera.

GRAM STAINING
Gram staining is the process for differentiating Gram positive and Gram negative bacteria. When the whole procedure of gram stain is followed and the slide is observed under the microscope, Gram positive bacteria appear Violet in color and Gram negative bacteria appear Pink in color.
For the gram staining we need Glass slide, Normal Saline, Inoculating loop, Bunsen burner, Crystal Violet, Gram’s Iodine, Acetone, Safranine.

PROCESS :

  1. The isolated colony of the microorganism is taken and in the drop of normal saline on the glass slide the colony is mixed with the help of inoculating loop to make a smear. The prepared smear is heat fixed.
  2. A staining rack is taken and on the smear, Crystal Violet is added. After 1 minute, the stain was removed by washing the slide in running water.
  3. After that, Gram’s Iodine is added on the smear as a decolorizing agent which is again washed after 1 minute under the running tap water.
  4. The next step is to add Acetone on the smear which is added in the hand to hand process.
  5. After the decolorisation is done, Safranine is added on the smear which is also washed after 1 minute.
  6. The glass slide is then air dried and observed under the microscope.

RESULTS :
It was observed under the microscope that the Gram positive bacteria appear Violet in color due to Crystal Violet stain whereas Gram negative bacteria appear Pink in color due to safranine.

TESTS ANALYZED
The tests analyzed in the microbiology section of the laboratory are basically the culture and sensitivities tests of urine, stool, sputum, pus swab etc.
The basic procedure of performing all the tests are :

  1. First of all, all the tests are performed inside the laminar flow hood.
  2. The samples collected from the patients and the media plates are kept inside the laminar flow.
  3. The inoculating wire loop is heat sterilized and with the help of it, the samples are cultured or streaked on the media plates.
  4. After inoculation, the cultured media plates are incubated for 24 hours (48 hours if necessary) for allowing the growth of bacteria.
  5. After the growth, staining is done or sensitivities are checked according to the requirement by the doctor.
  6. The report is prepared for the patient.