Influence of tetracycline resistance on the transport of manure-derived Escherichia coli in saturated porous media

Abstract

In this research, tetracycline resistant (tet R ) and tetracycline susceptible (tet S ) Escherichia coli isolates were retrieved from dairy manure and the influence of tetracycline resistance on the transport of E. coli in saturated porous media was investigated through laboratory column transport experiments. Experimental results showed that tet R E. coli strains had higher mobility than the tet S strains in saturated porous media. Measurements of cell surface properties suggested that tet R E. coli strains exhibited lower zeta potentials than the tet S strains. Because the surface of clean quartz sands is negatively charged, the repulsive electrostatic double layer (EDL) interaction between the tet R cells and the surface of sands was stronger and thus facilitated the transport of the tet R cells. Although no difference was observed in surface acidity, cell size, lipopolysaccharides (LPS) sugar content and cell-bound protein levels between the tet R and tet S strains, they displayed distinct outer membrane protein (OMP) profiles. It was likely that the difference in OMPs, some potentially related to drug efflux pumps, between the tet R and tet S strains led to alteration in cell surface properties which in turn affected cell transport in saturated porous media. Findings from this research suggested that manure-derived tet R E. coli could spread more widely in the groundwater system and pose serious public health risks.

Influence of Desiccation on the Transport of Escherichia coli through Saturated Sand Packs

“…Our previous results showed that the deposition rate coefficients calculated using Eq. 1 were similar to those estimated using mathematical models that consider the blocking effects of retained bacterial cells on the surface of the solid matrix (i.e., the Langmuir type of model; Walczak et al 2011). …”

The effects of starvation on the transport of Escherichia coli in saturated porous media are dependent on pH and ionic strength

“…It is well known that E. coli K12 cells lack O-antigen (the repeating polysaccharide component of LPS) [54], as a result, the values obtained in this research (2–6 μg/10 8 cells) were significantly lower than those measured for many environmental E. coli strains [25, 34]. …”

“…The deposition rate coefficients under clean-bed conditions ( K d , min −1 ) can be determined from the breakthrough concentration of bacterial cells using the following equation [32–34]…”

“…The lipids and polysaccharides are linked to form the lipopolysaccharide (LPS) complex, which is exposed to the environment and can affect cell mobility [37, 38]. The proteins are anchored within the membrane and several recent studies have shown that outer membrane proteins (OMPs) could have strong influences on bacterial transport through altering cell surface properties (e.g., hydrophobicity) [34, 39, 40]. …”

Numerical simulations of fluid dynamics in carrier structures for catalysis: characterization and need for optimization

“…A wellknown example is from the field of automotive applications, more precisely the catalytic converter (Shuai and Wang, 2004). Porous media are also used in other fields of engineering, in waste water treatment as a filter (Janzen et al, 2009), in bacteria transport in connection with groundwater decontamination (Walczak et al, 2011) and in the food industry (Braeken et al, 2004).…”