Escherichia Coli (e. Coli)

Escherichia Coli (E. Coli)

In this experiment, the microbes used here is E. Coli where this bacteria is cultured in several medium like broth tube, slant agar, deep agar and agar plate. This experiment is conducted in order to find out the bacteria colonial morphology, its mobility and its cultural characteristics.

The first experiment is transferring the inoculums into the broth tube containing liquid media which is nutrient broth. The tool used to transfer the microbes was inoculating loop so that the specimens can be transferred properly. According to the result which can be viewed in 24 hours later, the clear nutrient broth has turned cloudy or turbid. This showed that E.Coli specimens are present in the broth tube. Based on further observation, the microbes are seen on the bottom of the broth tube so its cultural characteristics can be referred as settled-diffuse. The characteristic for bacteria that is settled- diffuse is that it is not prone to oxygen because it can survive at the bottom of the broth tube which contains lowest oxygen percentage. Nutrient broth is not a selective medium for micro bacterial growth so E. Coli can survive in it without any problems.

The second experiment is transferring the inoculums into slant agar. Based on the observation conducted, the result suggested that E. Coli is filiform in movement. Moreover, the bacteria was seen living on the lower part of the slant showing that E. Coli is not an oxygen dependent microorganism because there is less oxygen at the bottom part of the slant compared to the upper part. As for deep agar tube, it is used to determine the motility of microbes, in this case the E. Coli. The stab morphology of E.Coli can be seen clearly as nutrient agar is clear and has a see through characteristics. The E. Coli has taken up filiform mode of motility. This means that the bacteria move in a straight line as is went down the nutrient tube.

There are also several important precautions in transferring the inoculums into the medium agar which is to always make sure that the lip of test tubes are flamed briefly so that any contaminations can be avoided. Besides that, make sure that the inoculating loop is properly sterilized before and after transferring the bacteria. Also ensure that the inoculating loop or stab wire containing the inoculums does not touch the wall of the tubes so that the inoculums are not transferred to the wrong place.

The final identification of E. Coli bacteria is conducted via agar plate through streaking and spreading technique. In both technique the E. Coli are spread and streaked on two different agar which are nutrient agar and MacConkey agar, based on the observation conducted on both streaking agar, the E. Coli colonies can be seen having a circular form and a raised elevation. The margin for E. Coli on the agar plate is entire. Streaking is a method use to obtain a single colony of bacteria without

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