The Effect of Lactobacillus acidophilus on the health of human skin

Abstract:
Concentration of Hydrogen Ions
(mol)
0.01
0.008
0.006
Before
0.004
After
0.002
0
1 2 3 4 5 6 7 8 9 10 11
Control Individuals (50% glycerol)
Figures 3: The two-tailed P value equals 0.0949
0.012
0.01
0.008
0.006
Before
0.004
After
0.002
0
1 2 3 4 5 6 7 8 9 10 11
Individuals that Received Bacteria (50%glycerol/
L. acidophilus)
0.008
0.006
0.004
0.002
0
-0.002
Glycerol
-0.004
Figure 4: The two-tailed P value equals 0.1794
Glycerol + L.
acidophilus
Figure 5: The P value equals 0.7507
12
10
8
6
Before
4
After
2
8
7
6
5
4
3
2
1
0
Before
After
1
0
2
3 4 5 6
7
Figure 8: The two-tailed P value equals 0.1572
Other Staphylococci Before/After 1
Week (Control)
100
80
Before
After
40
20
0
1 2 3 4 5 6 7 8 9 10 11
Control Individuals (50% glycerol)
Figures 10: The two-tailed P value equals 0.2473
Number of Staphylococci CFUs
Number of Staphylococci CFUs
Figure 2: Example of an inoculated
MSA plate. Yellow colonies are
pathogenic, Staphylococcus aureus
and the others are non-pathogenic
Staphylococci
1.3
100
90
80
70
60
50
40
30
20
10
0
1.2
•
After
16
Glycerol
14
Glycerol + L.
acidophilus
12
Figure 11: The two-tailed P value equals 0.0514
•
•
•
Application of both the control lotion and
experimental lotion resulted in a substantial decrease
in skin pH
Application of both lotions resulted in a decrease in
the presence of both S. aureus and nonpathogenic Staphylococci on the skin
There was no significant difference between the
effects of the control vs. experimental lotions
No L. acidophilus was recovered from skin prior to- or
following any application for any subject
Glycerol itself, may be responsible for lowering skin
pH and reducing numbers of Staphylococcal species
The psychological effect of applying lotion may have
caused a change in behavior in subjects lending to the
observed results
The small number of subjects as well as substantial
variability of results among subjects will need to be
addressed in future studies
10
8
6
4
1 2 3 4 5 6 7 8 9 10 11
Individuals that Received Bacteria
(50%glycerol/ L. acidophilus)
•
•
Average Decrease in Skin CFU of NonPathogenic Staphylococcus Following
Application.
18
Before
•
1.25
Figure 9: Shows the overall average decrease
between the control and bacterial groups
Other Staphylococci Before/After 1
Week (Bacteria)
120
60
1.35
8 9 10 11
Can repeated use of L. acidophilus lotion reduce the skins pH and inhibit the
growth of skin Staphylococci?
Materials and Methods:
Glycerol +
L.
acidophilus
1.15
Figure 7: The two-tailed P value equals 0.2674
Results/Conclusions:
1.4
Individuals that Received Bacteria
(50%glycerol/ L. acidophilus)
1 2 3 4 5 6 7 8 9 10 11
Control Individuals (50% glycerol)
Research Question:
Glycerol
1.45
Decrease in CFU
14
Decrease in CFU
Figure 1: Dropper bottle that was
given to the participants
Average Decrease in Staphylococcus
aureus Skin CFU Following
Application
1.5
S. aureus Before/After 1 Week
(Bacteria)
Number of S. aureus CFUs
S. aureus Before/After 1 Week
(Control)
• L. acidophilus is a part of normal human flora (mouth, intestines, vagina)
• L. acidophilus causes a decrease in pH by secreting lactic acid (a byproduct of
fermentation). This decrease in pH is inhibitory to other microorganisms.
• L. acidophilus may also secrete bacteriocins which inhibit the growth of
similar or related bacterial strains.
This study was approved by the Waynesburg University IRB
• L. acidophilus was suspended in 50% glycerol at a concentration that
matched a 0.5 McFarland standard (0.5 McFarland= 1.5 x 10^8 CFU /mL)
• A pH pen (Hydrion) was used to determine skin pH
• Subjects we given a dropper bottle containing 25mL of either 50% glycerol
or 50% glycerol and L. acidophilus (see figure 1)
• Subjects were directed to spread a dime-sized amount over a designated
area of their non-dominant forearm twice daily for 1 week.
• Two swabs of the participants forearms were taken before and after 1 week
• Mannitol Salt Agar was used to determine the presence of staphylococci on
participants skin before and after 1 week (see figure 2)
• Lactobacillus Selective Agar was used to determine if L. acidophilus was
present on participants skin before and after the 1 week
0.01
Gram stain of L. acidophilus.
Number of S. aureus CFUs
Introduction:
0.012
Concentration of Hydrogen Ions
(mol)
Probiotic bacteria have been used serendipitously for thousands of years in the
form of yogurt. Only recently, however, have the health benefits become fully
recognized. As a result, a variety of probiotic supplements have been marketed
to improve digestive health. As the scientific community becomes more
knowledgeable of the far-reaching health benefits of our body’s natural
microbial commensals, we are beginning to envision a potential for probiotic
therapies beyond digestive health. The purpose of our research was to
determine if a probiotic lotion containing the bacterium, Lactobacillus
acidophilus (L. acidophilus), is a feasible option for maintaining the health of
skin. We sought to specifically determine whether or not repeated application
of L. acidophilus can decrease the pH of skin and otherwise inhibit the growth of
common skin microbes known to cause infections. To test this, a sample of
resident skin flora and skin pH was obtained from the forearms of consenting
college students prior to and following a two-week-long course of a bi-daily
application of a lotion containing glycerol, L. acidophilus and water. A blank
lotion containing glycerol and water was used as a control.
Change in pH (Measured as Average
Change in Concentration of
Hydrogen Ions) Following Skin
Application
Change in Hydrogen Ions Before/After 1
Week (Bacteria) (pH)
Change in
Concentration of Hydrogen Ions
(mol)
Change in Hydrogen Ions Before/After 1
Week (Control) (pH)
2
0
Figure 12: Shows the overall average decrease
between the control and bacterial groups
Acknowledgements:
I would like to thank Nancy Wrick and the Center for
Research and Development for printing this poster.
I would also like to thank Nicole Adams for helping me
with media preparations.