Saddleback Journal of Biology - Saddleback College

Fall 2009 Biology 3B Paper
juice with fructose or just fructose alone will
inhibit the growth of UTI by testing it on E. coli
growth.
Methods and Materials
Nutrient Agar for culturing Escherichia
coli was prepared on 4 November 2009 in the
biology lab at Saddleback College, Mission
Viejo, CA. 15 mL’s of the nutrient agar was
plated in 30 Petri dishes using the aseptic
technique. On 5 November 2009, 0.25 mL’s of
E. coli was lawn spread onto all 30 dishes.
Twenty mL of fructose with a 0.60 M
concentration was prepared. Twenty mL of
Kirkland Signature cranberry juice cocktail and
deionized water were poured into two 100 ml
beakers. One hundred and eighty chads were
made from Wattmans filter paper and autoclaved
for 2 hours. Two chads dipped in DI water were
placed on each of the first 10 Petri dishes as the
control group which makes n=20. Two chads
dipped in a previously prepared fructose solution
were placed on the each of the 10 petri dishes in
the second group. On each of the 10 Petri dishes
in the last group, the chads were dipped in
cranberry juice cocktail. All 30 Petri dishes were
placed in the incubator for 72 hours at 37°C. On
11 November 2009, the Petri dishes were
inspected and the zone of inhibition for each dish
was measured in centimeters. All data were
transferred to Microsoft Excel 2007 where
further statistical calculations were preformed.
Since a significant difference was found when a
single factor ANOVA test was run; a Bonferroni
correction test was done to compare the results
within the groups.
Results
The DI water Petri dishes had E. coli
growth on top of the chads therefore the zone of
inhibition was zero, while the fructose and
cranberry juice had no E. coli growth on the
chads with a ring absent of E. coli around it.
There was a significant difference between all
three groups (p = 0.0167) . The greatest
difference in inhibition zones was between the
DI water with zero cm and the cranberry juice
with a mean of 1.265 cm, while the smallest
difference was between the fructose with a mean
of 1cm and cranberry juice with a mean of
1.265cm.
Mean Zone of Inhibition (cm)
1.4
1.2
1
0.8
0.6
0.4
0.2
0
Cranberry Juice1
Fructose
Figure 1. The Cranberry Juice had the highest
amount of inhibition with a mean value of 1.265
cm. The Fructose also had a fairly close amount
of inhibition compared to the cranberry with a
mean value of 1 cm. The DI water had no
inhibition with a mean value of zero. The
ANOVA p-value found for the groups was
0.0167.
Discussion
Based on our results, it can be
concluded that cranberry juice does inhibit E.
coli growth thus inhibiting/preventing urinary
tract infection (UTI). The mean difference
between the control group and the experimental
groups was at least 1 cm. While cranberry juice
and fructose did have signs of inhibition, the
chads in the deionized water were completely
covered in E. coli. There was a greater difference
between cranberry juice and the DI water then
the fructose and the DI water. This suggests that
although cranberry juice was the main prohibitor,
the fructose in the cranberry juice has inhibitory
factors as well. Zafiri et al. (1989) found that the
fructose in cranberry juice and cocktails inhibits
the adherence of type 1 fimbriae of E. coli to the
urinary tract epithelial cells. He also found that
there are two types of inhibitors in cranberry
juice, a nondialyzable and a dialyzable one. It
was brought to his attention that the main
inhibitor was the dialyzable one. The finding
that both cranberry juice cocktail and 5%
fructose inhibited yeast agglutination by purified
type 1 fimbriae proves that the fimbriae are the
target of inhibitory action. The P fimbriated
E.coli, was also inhibited by the cocktail. The
reason they were only inhibited by the cranberry
juice, was that the inhibitor was nondialyzable,
suggesting its high molecular weight.
In Ahuja’s study it was seen that the
growth of E. coli in cranberry rich agar inhibited
the attachment of the p receptor specific beads to
the epithelial tissue (1998). Until the chemical
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Saddleback Journal of Biology
Spring 2010