The morphology of the STEC-specific phages isolated from Salinas area.

<p>(A) O157-specific bacteriophage, (B) O145-specific bacteriophage, (C) O45-specific bacteriophage, (D) O179-specific bacteriophage.</p

Shiga toxin-producing <i>E</i>. <i>coli</i> (STEC) strains isolated from different sources by U.S. Department of Agriculture ARS used for free STEC-specific phage isolation.

<p>Shiga toxin-producing <i>E</i>. <i>coli</i> (STEC) strains isolated from different sources by U.S. Department of Agriculture ARS used for free STEC-specific phage isolation.</p

Geographical location of the watershed sites where the samples were collected in the area of Salinas Valley.

<p>Sample sites are labeled with a six-letter acronym in black type (locations with agriculture impact) or red type (locations with human impact). Insert is an expanded view of the area near the city of Salinas.</p

Summary of phage and STEC isolation data from water samples collected from Salinas, CA.

<p>The acronym is used for each sample site with the number of water samples collected. Red oval shape with red letter indicates isolation of STEC-specific phage, and green rectangular shape with green letters indicates STEC bacterial isolation.</p

Samples with positive of STEC-specific phages and STEC strains throughout sampling period displayed by sample month.

<p>Samples with positive of STEC-specific phages and STEC strains throughout sampling period displayed by sample month.</p

Effect of the environmental factors, rain precipitation and solar radiation, on the isolation of free STEC-specific phages from the overall sample sites.

<p>Effect of the environmental factors, rain precipitation and solar radiation, on the isolation of free STEC-specific phages from the overall sample sites.</p

Comparison of Subtypes of <i>Listeria monocytogenes</i> Isolates from Naturally Contaminated Watershed Samples with and without a Selective Secondary Enrichment

<div><p>Two enrichment methods for <i>Listeria monocytogenes</i> using Immuno Magnetic Separation (IMS) were tested to determine if they selected the same subtypes of isolates. Both methods used a non-selective primary enrichment and one included subculture in Fraser Broth, while the other involved direct plating of IMS beads. Sixty-two naturally contaminated watershed samples from the Central California Coast were used as a source of <i>L. monocytogenes</i>, and subtype diversity was measured by serotype and Multiple Number Variable Tandem Repeat Analysis (MLVA). Three different serotypes were detected from both methods with serotype 4b strains making up 87% of the isolates, serotype 1/2a making up 8%, and serotype 1/2b making up 5%. The data suggest that serotype 1/2a strains were more likely to be isolated from the Fraser Broth culture method. Sixty-two different MLVA types were detected and the more common MLVA types were detected by both culture methods. Forty-three MLVA types were detected only from one culture method or the other, while 19 types were detected from both culture methods. The most common MLVA type-12 was detected in 33 of the 62 water samples, and represented 31% of the isolates from both culture methods. This limited study provides evidence that using both enrichment culture methods allowed for detection of a greater diversity of isolates among the samples than the use of one method alone, and that a wide diversity of <i>L. monocytogenes</i> strains exist in this watershed.</p></div

MLVA types detected from more than one water sample and enrichment type from which they were isolated.

<p>MLVA types detected from more than one water sample and enrichment type from which they were isolated.</p

Primers and Dyes used for MLVA analysis.

a<p>Dye is shown in parentheses before primer sequence.</p

Parameters for <i>L. monocytogenes</i> VNTR Loci.

a<p>6-FAM: blue, VIC: green, NED: yellow.</p