1. Brandy Goudreau 1
Brandy Goudreau
Professor Tiffany Martin
Medical Microbiology
M/W/F 8:05am Fall 2016
#455 – Staphylococcus saprophyticus
Monday, November 07, 2016
Unknown #455 was identified as a gram positive organism by completing a gram stain. The results
demonstrated purple/violet, cocci singly, in pairs, and some irregular grape-like clusters. This also tested
positive for the catalase test.
Wednesday, November 9, 2016
Based on the gram stain observations, two tests were chosen to be inoculated.
Blood agar with Novobiocin was selected to determine whether the bacteria was beta-hemolytic, alpha-
hemolytic, gamma or non-hemolytic. The novobiocin disc was placed in the heavier inoculated quadrant
to see a zone of inhibition.
Mannitol Salt Agar (MSA) was selected for differentiation of Staphylococcus species. This was
inoculated by a straight line streak.
All of the inoculated media was left to incubate for 48 hours at about 35°C.
Figure 1: Gram Stain view from
microscope #455 11-7-16

2. Brandy Goudreau 2
Friday, November 11, 2016
The results are based on a 48-hour incubation period. All test results were cross-referenced against the
provided identification chart and by notes that were provided in lab.
Blood agar with Novobiocin was gamma or
non-hemolytic. There were no hemolysins
present. There was no change in the medium.
This also showed that this bacterium was
resistant to Novobiocin.
Mannitol Salt Agar (MSA) showed hot pink
which meant it was alkaline (-) for mannitol
fermentation. This was an unexpected result as
per the results from the blood agar. This
bacterium should have been (+) for mannitol
fermentation.
There was an additional test needed to confirm
the identity of this bacteria.
The DNA agar was chosen for Monday,
November 14, 2016. Figure 3: MSA agar #455 11-11-16
Figure 2: Blood agar w/ novobiocin #455 11-11-16

3. Brandy Goudreau 3
Monday, November 14, 2016
DNA agar was inoculated as an enzyme test to confirm the identity of the unknown bacteria.
The inoculated media was left to incubate for 48 hours at about 35°C.
Wednesday, November 16, 2016
DNA agar was viewed and there was a slight clearing
of the media but not enough to be considered a break
down. This result was read as (-) for DNase.
Figure 4: DNA agar #455 11-16-16
Data Summary
The following is a summary of tests used to identify unknown #455:
MEDIA PURPOSE OF TEST INOCULATION
METHOD
TEST RESULTS
Blood Agar
Breakdown of hemoglobin “modified” streaking for
isolation
Gama- no hemolysis present/no change in
media
MSA agar
Isolation and differentiation
of Staph. Species
Single straight line streak Hot pink = alkaline = (-) for mannitol
fermentation
DNA agar Lactose fermentation Single straight line streak No halo = (-) for DNase
Conclusion
Based on the above test results and the concurrence with the provided identification chart, bacteria #455
is Staphylococcus saprophyticus.