Antecedent Growth Conditions Alter Retention of Environmental <i>Escherichia coli</i> Isolates in Transiently Wetted Porous Media

The physical transport of Escherichia coli in terrestrial environments may require control to prevent its dissemination from potential high-density sources, such as confined animal feedlot operations. Biobarriers, wherein convective flows carrying pathogens pass through a porous matrix with high retentive capacity, may present one such approach. Eight environmental E. coli isolates were selected to conduct operational retention tests (ORT) with potential biobarrier materials Pyrax or dolomite, or silica glass as control. The conditions in the ORT were chosen to simulate conditioning by manure solutes, a pulse application of a bacterial load followed by rainfall infiltration, and natural drainage.Removal was limited, and likely caused by the relatively high velocities during drainage, and the conditioning of otherwise favorable adhesion sites. Flagella-mediated motility showed the strongest correlation to biobarrier retention. Significant variability was observed across the E. coli isolates, but consistently higher retention was observed for cells with external versus intestinal pregrowth histories. E. coli O157:H7 was retained the least with all examined matrices, while E. coli K-12 displayed moderate retention and may not serve as representative model strain. Pyrax is a good candidate biobarrier material given its superior removal ability across the tested E. coli strains

Definitions of main conditions involved in the sequelae of otitis media.

<p>Definitions of main conditions involved in the sequelae of otitis media.</p

OM-associated mortality estimates for the year 2005 per ten million people, by the 21 WHO regions.

<p>OM-associated mortality estimates for the year 2005 per ten million people, by the 21 WHO regions.</p

AOM and CSOM incidence rate, HI prevalence and mortality estimates for the year 2005, by WHO areas.

<p>AOM and CSOM incidence rate, HI prevalence and mortality estimates for the year 2005, by WHO areas.</p

OM-associated HI (>25 dB for best ear) prevalence rate estimates for the year 2005 per ten thousand people, by the 21 WHO regions.

<p>OM-associated HI (>25 dB for best ear) prevalence rate estimates for the year 2005 per ten thousand people, by the 21 WHO regions.</p

AOM incidence rate estimates for the year 2005 per hundred people, by the 21 WHO regions.

<p>AOM incidence rate estimates for the year 2005 per hundred people, by the 21 WHO regions.</p

Sequelae of OM (complete scheme) with ICD-10-CM diagnosis codes.

<p>Sequelae of OM (complete scheme) with ICD-10-CM diagnosis codes.</p

CSOM incidence rate estimates for the year 2005 per thousand people, by the 21 WHO regions.

<p>CSOM incidence rate estimates for the year 2005 per thousand people, by the 21 WHO regions.</p

Screening process of articles on epidemiology of AOM, CSOM and HI, according to the PRISMA 2009 Flow Diagram.

<p>AOM: Acute Otitis Media; CSOM: Chronic Suppurative Otitis Media; HI: Hearing Impairment.</p

Global AOM and CSOM incidence rate, HI prevalence and mortality estimates for the year 2005, by WHO age groups.

<p>Global AOM and CSOM incidence rate, HI prevalence and mortality estimates for the year 2005, by WHO age groups.</p