Antibiotic sensitivity test on micro organisms.

Antibiotic means the chemical or substances origin from organisms (mainly micro organism) which act as the inhibitor of other organism. Some antibiotic kill the organism/microorganism directly and some inhibit their growth. The antibiotic sensitivity test implicates the degrees of effectiveness of any antibiotic as an inhibitor to any other organisms or microorganisms.

Requirements for Antibiotic sensitivity test:

To complete the experiment the following equipment were used

  • Cultured bacteria in test-tube and Petri dish
  • Nutrient broth
  • Micropipettes
  • Petri dish and glass rod
  • Antibiotic disc
  • Forceps and
  • Oven

Procedure of Antibiotic sensitivity test:

At first 1ml of supplied and cultured bacteria was taken in a Petri dish with the help of micropipette then the solution was spread throughout the Petri dish with the glass rod. If accidentally excess media pour into the Petri dish then the excess media with bacteria has been cast away from Petri dish and then it was covered and left for some time. After then the supplied antibiotic disc were placed into the bacteria enrich medium on the Petri dish. To observe the effectiveness of the antibiotics on bacterial growth the Petri dish was left for 24 hours at 37c in the oven.

Result and observation of Antibiotic sensitivity test:

Finally it was observed that there were rounded zones around some of the antibiotic disc and on the other hand there were no zones around some antibiotic disc.

So we can say that, the antibiotics which made quite 15mm of zone were susceptible to the supplied bacteria and the antibiotics which made the zone of less than 15mm or fail to make a zone were resistance to the bacteria.

Do you like this post! Please share it with your friends.