A Motility Test Lab Report

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I. INTRODUTION
The worldwide the bacterial community includes billions of microorganisms. Microbiologist and other scientists are constantly working of identifying species and classifying them by morphological, biochemical and molecular tests. This is valuable to the medical community, as some of these microorganisms are pathogens, but also to other industries such as pharmaceuticals, foods and drinks production, ecological, agriculture and biotechnology as humans have used bacteria for years to fulfill their needs.
Likewise, morphological and biochemical testing were performed to identify the bacterial unknown for this project out of three possible options: Enterococcus faecalis, Enterobacter aerogenes, and Serratia marcescens. After careful
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The results confirm that bacterium is non-motile since growth along the stab line was observed only. The results of this test eliminate E. aerogenes, since is a motile bacterium, but also S.marcescens, only confirming E.faecalis. Research conducted by O’Rear, Alberti and Harshey regarding chemotaxis in S. marcescens indicates that certain mutation occur that affects its ability to swarm when grown on agar surface versus swim in a liquid environment. The strains that are capable of swarming require many genes in addition to those required in chemotaxis. Moreover, S. marcescens mutants can be very poor swarmers, defective in swarming or have altered patterns of swarming. The nonflagellate S. marcescens are cable of growing rapidly on agar media (O’Rear et al., 1992).
Of the three sugar fermentation tests available a lactose test has been performed to determine if the unknown is capable of using lactose as its carbon source. The results obtained, no color change or gas bubbles, indicate the unknown specimen is not a lactose fermenter, so it is not using lactose as its source of carbon (a color change would indicate a lactose fermenter). The test confirms only S.marcescens and successfully eliminates the other two possibilities (E.aerogenes and E.

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