Antibiotic molecules in geographically distinct honeys
Hannah Smith and Samantha Mascuch
Georgia Institute of Technology
Introduction
Conclusion
Results
*** P<0.0001
120
PERCENT BACTERIA KILLED
Ø  Due to the development of bacterial resistance, antibiotics
are becoming less effective and the discovery of new
treatments is vitally important. (1)
Ø  For centuries, honey has been known for its antibiotic
properties. (2)
Ø  Honey has been shown to kill gram positive and gram
negative bacteria.(3)
Ø  Knowledge of the chemical makeup of honey will reveal
the basis of its antibiotic activity.
Ø  The contribution of the free radical hydrogen peroxide to
bacterial killing was quantified. (4)
Manuka (New Zealand)
Brazil
100
VS
GaTech
80
Ø 
Ø 
Botanical Garden
Belvedere
60
Artificial Honey W/O pH change
40
Artificial Honey W/ pH change
20
Ø 
0
50.0%
35.7%
31.3%
27.5%
24.1%
HONEY CONCENTRATION
21.1%
Ø 
Figure 1. Honey kills bacteria. All honeys kill P. aeruginosa PAO1 at high
concentrations. Artificial honey also killed bacteria. One-way ANOVA was
used to determine significance.
Objective
Ø  To understand the molecular basis of the antibiotic activity
of honey
Ø  To determine whether there are differences in the antibiotic
activity of geographically distinct honeys against the gram
negative opportunistic pathogen Pseudomonas aeruginosa
PAO1 and molecular makeup of these different honeys
References
1. 
2. 
3. 
Geographical locations of honeys used
Ø  Novo Mel Brazilian
Rainforest Raw
Organic Honey
Ø  Manuka Honey
(New Zealand
Kiva, UMF 15+)
Methods
Ø  Experiment 1: Microdilution assay for bacterial killing at
different honey concentrations
Ø  Experiment 2: Quantification of honey hydrogen peroxide
(H2O2) content with EM Quant hydrogen peroxide test strips.
Strips were dipped into diluted honey samples. Strip color was
allowed to develop and compared to a scale provided by the
manufacturer.
Ø  Experiment 3: Inactivation of hydrogen peroxide with catalase
and testing in microdilution assay for antibiotic activity.
PERCENT BACTERIA STIMULATED PERCENT BACTERIA KILLED
Figure 2. Honey hydrogen peroxide content. Honeys contained differing
quantities of hydrogen peroxide. Honey from the Georgia Institute of
4. 
technology contained the highest concentration of hydrogen peroxide. Honey
from Belvedere contained the lowest concentration of hydrogen peroxide.
Ø  Georgia Institute of
Technology (2014)
Ø  Atlanta Botanical
Gardens (2013)
Ø  Belvedere (Decatur,
2014)
All honeys were able to kill P. aeruginosa PAO1 at
high concentrations
Because artificial honey also killed bacteria, it is
possible that some of the killing observed in the
natural honey may be due to high sugar content or
high osmolarity
Among these single batches of honey the high
variation of hydrogen peroxide concentration is not
matched by a high variation in antibiotic potentcy
In the absence of hydrogen peroxide, honey was still
antibiotic at high concentrations leading us to
conclude that there are additional antibiotic molecules
to be characterized
50.0%
44.6%
39.9%
35.6%
31.8%
125
100
28.4%
Manuka (New
Zealand) w/
catalase
Manuka (New
Zealand) w/o
catalase
Brazil w/ catalase
75
Brazil w/o catalase
50
GaTech w/ catalase
25
GaTech w/o
catalase
0
-25
Belvedere w/
catalase
-50
Belvedere w/o
catalase
-75
-100
Botanical Garden
w/ catalase
-125
Botanical Garden
w/o catalase
HONEY CONCENTRATION
Figure 3. Impact of H2O2 removal on bacterial killing. At 50%
honey concentration, honey samples remain antibiotic in the absence
of hydrogen peroxide. At 44.6% the ability of the honey to kill bacteria
is predominantly due to hydrogen peroxide.
Levy, S. B., Marshall, B.Antibacterial resistance worldwide:
causes, challenges and responses. Nat. Med. 2004:10;S122–
S129.
Kwakman PHS, Zaat SAJ. Antibacterial components of
honey. IUBMB Life. 2011;64(1):48-55.
Zainol, Mohd, Yusoff, Kamaruddin, Yusof, Mohd.
Antibacterial activity of selected Malaysian honey. BMC
Complementary and Alternative Medicine. 2013;13(1):
129-138
Brudzynski K. Effect of hydrogen peroxide on antibacterial
activities of Canadian honeys. Canadian journal of
microbiology. 2006:52(12):1228-1237.
Acknowledgements
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Ø 
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Dr. Julia Kubanek
Serge Lavoie
Remington Poulin
Dr. Jennifer Leavey
Georgia Institute of Technology Urban Honeybee Program
The United States Department of Agriculture (USDA)
Kubanek Laboratory Members
NIH International Cooperative Biodiversity Groups (ICBG)
(U19TW007401)
Ø  National Science Foundation (NSF) (A14039)