Distribution and Characteristics of Listeria monocytogenes Isolates from Surface Waters of the South Nation River Watershed, Ontario, Canada

Listeria monocytogenes is a facultative intracellular pathogen thought to be widely distributed in the environment. We investigated the prevalence and characteristics of L. monocytogenes isolates from surface waters derived from catchments within the South Nation River watershed (Ontario, Canada). T...

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Bibliographic Details
Published in:Applied and Environmental Microbiology 2007-09, Vol.73 (17), p.5401-5410
Main Authors: Lyautey, Emilie, Lapen, David R, Wilkes, Graham, McCleary, Katherine, Pagotto, Franco, Tyler, Kevin, Hartmann, Alain, Piveteau, Pascal, Rieu, Aurélie, Robertson, William J, Medeiros, Diane T, Edge, Thomas A, Gannon, Victor, Topp, Edward
Format: Article
Language:English
Subjects:
Agriculture
Animals
Anti-Bacterial Agents - pharmacology
Bacteria
Bacterial Typing Techniques
Biological and medical sciences
Culture Media
Ecology, environment
Ecosystem
Environmental impact
Environmental Microbiology
Freshwater
Fundamental and applied biological sciences. Psychology
Genotype
Humans
Life Sciences
Listeria monocytogenes
Listeria monocytogenes - classification
Listeria monocytogenes - genetics
Listeria monocytogenes - isolation & purification
Listeria monocytogenes - pathogenicity
Microbial Sensitivity Tests
Microbiology
Ontario
Phenotype
Rivers
Rivers - microbiology
Seasons
Social Planning
Surface water
Urban Renewal
Virulence - genetics
Watersheds
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Summary:Listeria monocytogenes is a facultative intracellular pathogen thought to be widely distributed in the environment. We investigated the prevalence and characteristics of L. monocytogenes isolates from surface waters derived from catchments within the South Nation River watershed (Ontario, Canada). This watershed is dominated by urban and rural development, livestock and crop production, and wildlife habitats. From June to November 2005, a total of 314 surface water samples were collected biweekly from 22 discrete sampling sites characterized by various upstream land uses. Presumptive Listeria spp. were isolated using a selective enrichment and isolation procedure, and 75 L. monocytogenes isolates were identified based on colony morphology, hemolytic activity, and amplification of three pathogenicity genes: iap, inlA, and hlyA. Thirty-two of 314 (10%) surface water samples were positive for the presence of L. monocytogenes, but detection ranged between 0 and 27% depending on the sampling date. Isolates belonging to serovar group 1/2a, 3a (50%) and group 4b, 4d, 4e (32%) were dominant. L. monocytogenes populations were resolved into 13 EcoRI ribotypes and 21 ApaI and 21 AscI pulsotypes. These had Simpson indexes of discrimination of up to 0.885. Lineage I-related isolates were dominant (61%) during the summer, whereas lineage II isolates were dominant (77%) in the fall. Isolates were, on average, resistant to 6.1 ± 2.1 antibiotics out of 17 tested. Half of the L. monocytogenes isolates exhibited potential virulence linked to the production of a functional internalin A, and some isolates were found to be moderately to highly virulent by in vitro Caco-2 plaque formation assay (up to 28% of entry). There was a statistically significant link between the occurrence of L. monocytogenes and proximity to an upstream dairy farm and degree of cropped land. Our data indicate that L. monocytogenes is widespread in the studied catchments, where it could represent a public health issue related to agricultural land use.
ISSN:0099-2240
1098-5336
DOI:10.1128/AEM.00354-07