Effects of surface characteristics on the transport of multiple Escherichia coli isolates in large scale columns of quartz sand - Transport of Multiple Escherichia Coli Transport in Saturated Porous Media - page 20

also between motility and the strain averaged sticking efficiency ( r = 0.72, p = 0.052). In AGW,
strain averaged sticking efficiency showed a high positive correlation with Ag43-expression, but
this correlation was not statistically significant ( r = 0.741, p = 0.076). The correlation between
strain averaged sticking efficiency and motility in AGW was low ( r = 0.42, p = 0.20).

Correlations of pairs of all cell properties were generally low and statistically not significant.
From these observations, we concluded that from the cell properties we studied, Ag43 expression
was the most important property determining attachment of E. coli , while under certain
conditions (the DI experiments) also motility played an important role.
We also determined the degree of correlation between the Α -values of all strains and E. coli cell
properties as a function of the transport distance. In both DI and AGW, the Pearson's correlation
coefficient between sticking efficiency and Ag43-expression showed the highest positive r -
values ( Figs. 2.3 and 2.4 )

In DI, r -values were not only positive, but also statistically significant for the first two sampling
ports (at 0.13 m: r = 0.87, p = 0.05 and at 0.33 m: r = 0.86, p = 0.02). At larger transport
distances, the Pearson's coefficient reduced, while the p -value increased, indicating less and less
correlation between sticking efficiency and Ag43-expression as transport distance increased.

Ag43
Motility
Hydrophobicity
Zeta potential
Sphericity

1

0.8

0.6

0.4

0.2

0

0 1 2 3 4 5

-0.2

-0.4

-0.6

Distance (m)

Fig.2.3: Pearson's correlation coefficient of the transport dependent sticking efficiency

and E. coli surface property for the DI experiments, as a function of the traveled
distance (m).