technique. Both samples revealed successful isolation. Unknown 10a was then subjected to tests for gram negative bacteria. Unknown 10b was tested with tests for identifying gram positive bacteria.Week 2, Day 2All test results were viewed and recorded.Unknown 10aLactose FermentationSulfur ReductionIndole ProductionMotilityUrease PresentCitrate UtilizationMetallic Green SheenNo color changePink ring formedYesNo color changeNo color changeUnknown 10a was positive for lactose fermentation, negative for sulfur reduction, positive for motility, Negative for the presence of urease and negative for Citrate utilization.Unknown 10bHemolysisMannitol FermentationCoagulase ActivityNo Color ChangeNo color changeNo clottingUnknown 10b participated in gamma lysis, could not ferment mannitol and did not have coagulase activity.ConclusionBy analyzing the results and using Bergey’s Manual of Determinative Bacteriology the identity of the unknown bacteria were found. Unknown 10a is Escherichia coli. Bergey’s Manual states that the genus Escherichia is made up of straight rods that occur singly or in pairs. The manual also states that the optimal growing temperature for this genus is 37 degrees Celsius. These two statements confirm the results found for Unknown 10a. Reviewing results from previous labs and consulting the lab manual confirmed all of the other test results. E. coli can ferment lactose, it can not reduce sulfur, it can produce indole, it is motile, there is no urease present and there is no coagulase activity. By deduction and logical reasoning Unknown 10a was determined to be Escherichia coli. Unknown 10b is Staphylococcus epidermidis. According to Bergey’s Manual Staphylococcus bacteria are gram positive spherical cells that occur singly, in pairs or in irregular clusters. Unknown 10b was gram positive, spherical and occurred in clusters. Bergey’s Manual also says the bacteria grow well in high salt conce...
