March 18-20 Repeat No 3- Staphylococcus Aerus

After observing the reactions that marine bacteria has towards differrent pathogens, I decided to choose the best reactions in antibiotic sensitivity that marine bacteria has towards a pathogen and repeat the plate in different medium and grow it at different temperature.

There were three temperatures been targeted to test the growth of pathogen and marine bacteria's sensitivity towards the pathogen and they are 4°C in the fridge, 24°C to 27°C room temperature and 37°C in the incubator with two different nutrient agar medium duplicated for each temperature- Marine Agar Medium and Distilled Nutrient Agar.

Materials:

Unsterilized: Two Distilled Nutrient Agar plates and Marine Nutrient Agar plates, amplicillin solution, Pathogen Staphylococcus Aerus, bacteria S1AI and K1AII microbe in broth, hockey stick, parafilm, pipette

Sterilized: Tips, disk filter paper in glass petri dish and scraper

For method, please refer to the previous post.

Observe result.

Result:
I was told to observe the result after 24 hours the petri dish been left in their intended temperature location. But then after researching about the optimum hour for the growth of marine bacteria, I stayed back in the lab untill late at night to observe it every 2-3 hours. As a result, I get much better view of the transforming result in the plate.

Round 1 (MNA+Staphylococcus+S1AI+K1AII):

The two pictures above showing Marine Nutrient Agar plate with the left 37°C and the right in room temperature. Noticed that the pathogen only grow well in 37°C temperatures (represent by the mass disordered white surface) but not in room temperature (compare with the picture on the right, but there are still some growth) and the marine bacteria, (labeled as S1AI and K1AII) grow well in room temperature but not in 37°C in the incubator. Even though the pathogen shows only a little bit of growth in room temperature, it is enough to determine whether the marine bacteria has antibiotic sensitivity reaction towards it or not.

The compartment of K1AII in picture on the right shows that there is a big hollow zone around the disk filter paper. It was obvious that it is a human error as the disk filter paper from that compartment might be wrongly dipped into Amplicillin solution. (Noticed that the hollow zone size of K1AII is the same as the hollow zone of Amplicillin solution.) As for S1AI, it is clear that there is some growth on picture in the right (represent by the yellow round 'sphere' around the disk filter paper of the S1AI compartment)

This plate has been repeated again on the same day and observed after 24 hours in the fridge and 6 hours after it been put in the intended temperature location.

Round 2 (DNA+Staphylococcus Aerus+S1aI+K1AII):

It is cleared that the pathogen grow happily in this medium and not for the marine bacteria. Marine bacteria almost shows no sign of growth at all except for S1AI. Clearly that S1AI has more strength for growth compared with K1AII, even though in room temperature (marked as amb which stands for ambient) This type of round will not be repeated as the marine bacteria cannot grow on Distilled Nutrient Agar at 37°C and ambient temperature.

Round 3 (MNA+Staphylococcus+S1AI+K1AII)
















In this round, the plate for MNA+Staphylococcus+S1AI+K1AII has been repeated in the exact same manner except that the result was observed earlier instead of waiting for after 24 hours. You can see that there are growth for both of the plates after 8 hours of putting it at the intended temperature location except that the picture for the left was at ambient temperature instead of 37°C. From this result I can determine that S1AI has stronger growth than K1AII and that K1AII is not able to fight the pathogen given compared to S1AI.






















The plate above was placed in the fridge at 4°C for 24 hours and then been taken out to put in ambient temperature after that. After 24 hours in ambient temperature the result is like above. Only S1AI shows growth and also the pathogen but not K1AII. From the picture you can see that S1AI is able to grow around its territory and that pathogen Staphylococcus Aerus is not able to fight with it. This again confirmed that S1AI has antibacterial sensitivity towards the pathogen of Staphylococcus Aerus.

S1AI vs K1AII
Out of curiosity, I performed an experiment to find out if S1AI and K1AII bacteria are friends or not, and if they are not are they able to fight each other? Who will win in the war of fighting each other? Thus, I used the same method that has been used on pathogen except that I removed pathogen and replaced it with S1AI and vise versa instead so that means there are only three compartments in the petri dish. The medium used was MNA.



































The pictures above was taken 6 hours after the plates been put in its intended temperature location. Two of this plates was put in room temperature for its growth. On the left is S1AI vs K1AII in which S1AI is the boss and its represented by the whole big yellow spot and K1AII is in one of the three compartment and grow from the disk filter paper only. You can see very clearly out of the three compartments, there is only one compartment that has yellow disk filter paper on it (K1AII) with yellow spot around it (which is S1AI). This show clearly that K1AII is not able to fight S1AI.

Reversely, in picture on the right, which is K1AII vs S1AI and you can see very clearly that there is a hollow zone around the only yellow disk filter paper (which is S1AI). This means that S1AI is showing antibiotic sensitivity towards K1AII by clearing the area around the disk filter paper.


















Picture above shows the hollow zone of S1AI to K1AII

The pictures below shows the plates after more than 12 hours. Notice that the color of the marine bacteria (yellow spot) has grown darker.



















In conclusion, only S1AI shows clear antibiotic sensitivity reaction to Staphylococcus Aerus and in between S1AI and K1AII, S1AI also shows antibiotic sensitivity towards K1AII while K1AII only shows a little reaction towards Staphylococcus Aerus.

Both of these marine bacteria will be proceed to DNA extraction which will be in the next post.