Identification of unknown Bacteria Research Paper

Identification of unknown Bacteria - Research Paper Example With regards to the aim of the experiment, which is to identify unknown bacteria from mixed culture #18 using biochemical and morphological test, the two organisms identified had distinct characteristics which were looked for following laboratory tests. Normally, Gram staining is employed to differentiate 2 bacteria groups with different cell wall constituent. The method has the ability to differentiate Gram negative and Gram positive bacteria group; thus the bacterial cells are either colored red or violet. Gram positive bacteria is shown by Violet staining due to a thick layer of peptidoglycan existing   in the cell wall of the bacteria, thus the crystal violet is retained by these cells on a slide. Consequently, Gram negative bacteria is shown by red staining due to a thin layer of peptidoglycan existing in the bacteria cell wall, hence crystal violet is not retained   by bacterial cells. (Winn et al,2006)MacConkey Agar is used to distinguish Gram- negative, lactose-fermenting organisms from organisms that are non-fermentative .It is an inhibitory and differential medium that contains Crystal violets, bile salts, inhibitory agent and neutral red. Neutral red acts as a pH indicator.   Klebsiella pneumoniae bacteria is known to be lactose fermenters hence unknown A while Salmonella Typhimurium bacteria is not lactose fermentor thus unknown B. The orinithine decarboxylase test is important for Enterobacteriaceae differentiation. (MacFaddin, 2000). MR-VP broth for Methyl Red test consists of peptone, phosphate buffer and glucose.