Bio 351 - General Microbiology
Concordia University, Irvine
February 24, 2012
Identifying Salmonella choleraesuis using Several Microbiology Lab Techniques
The purpose of this study was to determine what an unknown bacteria was using several different microbiology lab techniques including an API test, an oxidase test, a gram stain, a hanging drop slide, and morphology identification. The unknown bacterium, which was contaminated with Serratia marcescens, was isolated by streaking the bacteria solution to single colonies. The isolated unknown white bacteria, had the appearance of circular form, convex elevation, entire margin, elongated cocci. The tests than showed that the bacteria was gram-negative, non-motile, and was identified as a Salmonella species bacteria, Salmonella choleraesuis.
When applying biology to real world cases, it takes numerous tests to be able to identify exactly what a type of bacteria an unidentified bacterium is, whether it is a bacterium that is causing a person to be ill or a bacterium that is being studied in a laboratory. Often times a bacteria is taken from a contaminated sample that may contain more than one type of bacteria and therefore the specific bacteria that is to be identified has to be isolated. This can often be done by streaking the sample to single colonies. The individual colonies can then be put through several different tests that allow one to identify distinctive aspects of the bacteria. Some examples of these tests are a gram-stain and an API test. These tests allow one to figure out what properties a bacteria strain contains, such as gram negative or gram positive with the gram staining test, or what bacteria an unknown is based on positives and negative of the API test. The results of API tests, will show extremely accurately what a bacteria is based on previous tests performed. One such bacteria than can be identified is Salmonella choleraesuis. There have been many...
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