Microflora Lab Report

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This laboratory experiment investigated how different types of media plates affect the growth of skin microflora mainly microflora in the nostril It was hypothesized that the nostril microflora were gram-positive bacteria that belong to the genera Streptococcus, Staphylococcus and Propionibacteria. Results showed that the nostril microfloras were gram-positive (stained purple). However, gram staining was not enough to prove that the bacterium obtained from the nostril are Streptococcus, Staphylococcus, and Propionibacteria spp. The results do not fully support the hypothesis.

All Fastidious microorganism rely on specific nutrients to grow, as a result, microbiologists who study the growth of bacteria need to provide
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Wash with 95% ethanol and wash with water after 15 seconds.
7. Stained counterstain with fuchsine and wash with water after 60 seconds.
8. Remove excess water from the surface of the gram stained glass slide and observed under 1000X oil immersion microscope.
Gram-staining have performed for Staphylococcus aureus (control); Enterococcus faecalis (control); Nostril microflora in NA, MSA, and PYCa. Gram-staining provides results of the bacteria morphology, type of gram-stain. Catalase test was also done prior to gram-staining.
MicrobactTM Biochemical Identification Kit was used for identifying gram-negative aerobic and facultatively anaerobic bacteria. Hence 3 unknown gram-negative bacteria samples were given. MicrobactTM Biochemical Identification Kit was done in identifying the 3 unknown bacteria samples in the following order:
1. Each of the isolated colony (sample) were added to sterile saline.
2. The saline solution of the sample is then added to the 24 wells of the kit to approximately 75% full.
3. Wells 1,2,20 and 24 are overlaid with sterile mineral oil.
4. In the last set of 24 wells of the kit, sterile saline was also added to the 24 wells to act as the control for this
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The purpose of the catalase test was used to identify the catalase positive bacteria (staphylococci) and catalase negative bacteria(streptococci). The results were as follows:
Staphylococcus aureus (control)- catalase positive
Enterococcus faecalis(control)- catalase negative
Nostril Microflora on NA- catalase positive
Nostril Microflora on PYCa- catalase negative
Nostril Microflora on MSA- catalase positive

Figure 1. Staphylococcus aureus gram stain control Figure 2. Enterococcus faecalis gram stain control
Staphylococcus aureus and Enterococcus faecalis were used as control in both catalase test and gram staining

Figure 3. Nostril Microflora on NA plate-gram stain Figure 4. Nostril Microflora on MSA plate-gram stain

Figure 5. Nostril Microflora on PYCa plate- gram stain
The following table 1 were the results of the cell morphology, catalase test and the gram stain;
Source of colony Staphylococcus aureus Enterococcus faecalis NA MSA PYCa
Colony description
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