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Open Access Research

Molecular characterization of Listeria monocytogenes isolated from fresh seafood samples in Iran

Hassan Momtaz1* and Shole Yadollahi2

Author Affiliations

1 Department of Microbiology, College of Veterinary Medicine, ShahreKord Branch, Islamic Azad University, ShahreKord, Iran

2 Post graduated of Master of Science of Microbiology, Falavarjan Branch, Islamic Azad University, Falavarjan, Iran

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Diagnostic Pathology 2013, 8:149  doi:10.1186/1746-1596-8-149

Published: 13 September 2013

Abstract

Background

Among all species of Listeria, Listeria monocytogenes (L. monocytogenes) is a major pathogenic microorganism of humans and animals and L. ivanovii is rarely pathogenic for humans. The objective of this study was to isolate and characterize Listeria species and to determine the frequencies of virulence genes in L. monocytogenes serotypes in fresh fish, shrimp, crab and lobster in Isfahan and Shahrekord, Iran.

Methods

From September 2010 to April 2011, a total of 300 marine food samples were purchased from supermarkets of Isfahan and Shahrekord cities, Iran. All samples were cultured and the positive samples for L. monocytogenes were analyzed for presence of serotypes and virulence genes.

Results

From the total 300 samples, 23 (10.45%) fresh fish and 1 (2.5%) shrimp samples were positive for Listeria spp., but there were no positive lobster and crab samples for Listeria species. Only L. monocytogenes was isolated from 17 fish (7.25%) and 1 shrimp (2.5%) samples while L. innocua, L. ivanovii and L. seeligeri only detected in fish samples (2 (0.9%), 3 (1.36%) and 1 (0.45%)), respectively. The plcA, prfA, actA, hlyA and iap virulence genes were detected in all of the 18‚ÄČL. monocytogenes isolates. Totally, the 4b, 1/2a and 1/2b serotypes were detected in 66.66%, 5.55% and 27.77% bacterial isolates, respectively.

Conclusions

Consumption of these sea foods, either raw or undercooked, may contribute to food-borne illness due to L. monocytogenes in Iran. The hygienic quality of sea food products should be observe.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/3422944359800606 webcite

Keywords:
Listeria spp; Listeria monocytogenes; Virulence factors; Serotypes; Seafood; Iran