Synergistic Drug Effects on Microbial
Flora
By: Luke Beck
Pittsburgh Central Catholic HS
PJAS 2012
Grade 11
Problem
 Accompanied with drug side effects, combination
of over the counter drugs can have dire side
effects
 Do common daily over the counter drugs cause
adverse effects on human cells?
Ibuprofen
 A nonsteroidal antiinflammatory drug
 Used to treat such symptoms
as headache, muscular aches,
the common cold and arthritis
pain.
 Third most consumed drug in
the entire world.
 Can be taken on a daily basis to
prevent symptoms.
Benadryl
 Active Ingredient:
Diphenhydramine Hydrochloride
 Used as an Antihistamine
 Over 25 over the counter drugs
share the same active ingredient
as Benadryl
 Taken on a daily basis to prevent
allergy symptoms
Escherichia Coli
 Has been the most studied type of
bacteria in biological research.
 Gram negative bacteria
 Symbiont in intestinal tracts of
many mammals, including humans.
 Mostly non-pathogenic.
Staphylococcus epidermidis
 Staph. species consisting
harmless skin-dwelling
microorganisms
 Species of Staph. are
commonly used in
microbiological
experiments
 Gram Positive Bacteria
Purpose
 To determine if differing concentrations of
Ibuprofen, the antihistamine Benadryl and/or
synergy of the two have an adverse effect on E.
Coli and Staph. Survivorship.
Hypothesis
 Null: The presence of
Ibuprofen, Benadryl,
and a combination of
both will not cause a
change in bacterial
population outside of
chance
 Alternative: The presence
of Ibuprofen, Benadryl,
and a combination of
both will cause a change
in bacterial population
outside of chance
Materials
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Ibuprofen (200mg liquid gels)
Benadryl (25mg liquid gels)
Escherichia coli bacteria
Staphylococcus epidermidis
bacteria
Ethanol
20 mL tubes
Sterile
Micro burner
Ethanol
Test tubes
Test Tube Rack
Microtubes
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Vortex
Incubator
Gloves
Goggles
Klett Spectrophotometer
SDF
LB agar plates (1% Tryptone, 0.5%
Yeast Extract, 1% NaCl)
 Sidearm flask
 Spreader bar
 SDF Test Tubes
Procedure
1. Bacteria (E. coli and Staph) was grown overnight in sterile LB
media.
2. A sample of the overnight culture was added to fresh media in
a sterile sidearm flask.
3. The culture was placed in an incubator (37°C) until a density of
50 Klett spectrophotometer units was reached. This
represents a cell density of approximately 108 cells/mL.
4. The culture was diluted in sterile dilution fluid to a
concentration of approximately 105 cells/mL.
Concentrations
(Ibuprofen, Control
Benadryl)
(0 x,
0.01x)
(0 x, 0.1 x) (0.1 x, 0 x) (0.1 x,
0.01 x)
(0.1 x,
0.1 x)
(1 x, 0 x)
(1 x,
0.01 x)
(1 x, 0.1 x)
Microbe
E. Coli or
Staph.
0.1 mL
0.1 mL
0.1 mL
0.1 mL
0.1 mL
0.1 mL
0.1 mL
0.1 mL
0.1 mL
SDF
9.9 mL
9.89 mL
9.8 mL
9.8 mL
9.79 mL
9.7 mL
8.9 mL
8.89 mL
8.8 mL
Ibuprofen
0 mL
0 mL
0 mL
0.1 mL
0.1 mL
0.1 mL
1.0 mL
1.0 mL
1.0 mL
Benadryl
0 mL
0.01 mL
0.1 mL
0 mL
0.01 mL
0.1 mL
0 mL
0.01 mL
0.1 mL
Total
10 mL
10 mL
10 mL
10 mL
10 mL
10 mL
10 mL
10 mL
10 mL
Procedure
 100 µL of cell culture was then added to each solution, yielding a final
volume of 10 mL and a cell density of approximately 103 cells/mL.
 The solutions were vortexed and allowed to sit at room temperature
for 15 minutes.
 After vortexing to evenly suspend the cells, 100 µL aliquots were
removed from the tubes and spread on LB agar plates.
 The plates were incubated at 37°C for 48 hours.
 The resulting colonies were counted visually. Each colony was assumed
to have arisen from one cell.
ANOVA
 Abbreviation for analysis of variance
 Statistical test comparing variation within and
between experimental groups
 If the P- value is lower than the alpha value (.05), then
the result is significant (a result of the variable
influence)
 Two factor: verifies interaction between two
variables.
Staph Survivorship
140
P-Value: .0508
120
100
Number of Colonies
80
60
40
20
0
0x. 0x
0x, .01x
0x, .1x
.1x, 0x
.1x, .01x
.1x, .1x
Concentration (Ibuprofen, Benadryl)
1x, 0x
1x, .01x
1x, .1x
E. Coli Survivorship
140
P-Value: 0.7921
120
Number of Colonies
100
80
60
40
20
0
0x, 0x
0x, .01x
0x, .1x
.1x, 0x
.1x, .01x
.1x, .1x
Concentration (Ibuprofen, Benadryl)
1x, 0x
1x, .01x
1x, .1x
Conclusion
 The presence of Ibuprofen, Benadryl, and a
combination of the two drugs did not significantly
change the number of Staphylococcus epidermidis or
E. Coli.
 The null hypothesis can be accepted.
 The alternative hypothesis can be rejected
Extensions Limitations
 Try prescription
medication combination.
 Test synergy effects of
more harmful drugs.
 Use human cells rather
than bacteria.
 These bacteria were only
models for the human
cell.
 Plates were not plated
simultaneously.
Works Cited
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http://www.drugs.com/pro/ibuprofen-drug-facts.html
http://textbookofbacteriology.net/staph.html
http://www.bacterio.cict.fr/e/escherichia.html
http://www.textbookofbacteriology.net/e.coli.html
http://www.drugs.com/mtm/benadryl.html
http://www.mayoclinic.com/health/endocarditis/DS00
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