Microbiology Notes

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Microbiology Laboratory Report
Identification of Unknown Bacteria 6O
BIO 251-7H1

Gram Stain

Summary:
Out of 28 Unknown microorganisms, slant 6O was randomly selected, and subjected to testing in order to identify it’s species. Seventeen of the unknown bacteria were classified as Gram-negative bacilli: Corynebacterium pseudodiphtheriticum, Enterobacter aerogenes, Eschirichia coli, Flavobacter capsulatum, Helicobacter pylori, Klebsiella pneumonia, Klebsiella oxytoca, Proteus hauseri, Proteus mirabilis, Proteus vulgaris, Pseudomonas aeroginsoa, Alcaligenes faecalis, Rhizobium radiobacter, Salmonella typi, Serratia marcescnes, Shigella flexneri, or Yersina pseudo tuberculosis. Ten of the unknown bacteria were classified as Gram-positive bacilli: Bacillus cereus, Bacillus circulans, Bacillus coagulans, Bacillus megaterium, Bacillus subtilis, Bacillus thuringiensis, Brevibacillus brevis, Geobacillus stereothermophilus, Lysinibacillus sphaericus, Clostridium perfringens. Lastly, there were also 11 Gram-positive cocci microbes: Enterococcus faecalis (Streptococcus), Streptococcus lactis (Lactococcus), Streptococcus mutans, Streptococcus pneumoniae, Micrococcus (Kocuria) roseus, Sarcina lutea (Micrococcus luteus), Sporosarcina ureae, Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus saprophyticus, Rhodococcus rhodochorous.

Procedure:
A gram stain was performed to identify if unknown 6O is a gram positive or gram negative and determine its shape. The gram stain was performed as stated in Laboratory Exercises In Microbiology, 8th Ed, pages 45-49 (Harley, 2011). A minor adjustment was made in the process of decolorization with crystal violet, allowing the time to be reduced to 20 seconds to prevent over decolorization.

Purpose:
In order to determine a unknown microbe, a gram stain is the first procedure used to determine if the bacteria is a gram negative or a gram positive. This process will eliminate a substantial...
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