title: Detection and quantification of Vibrio parahaemolyticus in shellfish from Italian production areas.
abstract: Vibrio parahaemolyticus is a marine microorganism, recognized as an important cause of foodborne illness particularly in Asia, South America and United States. Outbreaks are rarely reported in Europe, but they can occur unexpectedly in relation, among other reasons, to the spread of highly virulent strains. It is known that the risk is proportional to exposure levels to pathogenic V. parahaemolyticus (i.e. carrying the tdh and/or the trh genes) but currently there is a lack of occurrence data for pathogenic V. parahaemolyticus in shellfish production areas of the Member States. In this study a total of 147 samples of bivalve molluscs, from harvesting areas of two Italian regions (Sardinia and Veneto) were analyzed for Escherichia coli and salmonella, according to Reg 2073/2005, and for detection and enumeration of total and toxigenic V. parahaemolyticus strains using a new DNA colony hybridization method. Environmental parameters (water temperature and salinity) were also recorded. Results of E. coli were consistently in agreement with the legislation limits for the harvesting class of origin and Salmonella was detected only in one sample. The average contamination levels for total V. parahaemolyticus were 84 and 73 CFU/g respectively for Sardinia and Veneto, with the highest value reaching 8.7 × 10(3)CFU/g. Nineteen samples (12.9%) resulted positive for the presence of potentially pathogenic V. parahaemolyticus strains, with levels ranging between 10 and 120 CFU/g and most of the positive samples (n=17) showing values equal or below 20 CFU/g. A significant correlation (r=0.41) was found between water temperature and V. parahaemolyticus levels, as well as with isolation frequency. The data provided in this study on contamination levels of total and potentially pathogenic V. parahaemolyticus, seasonal distribution and correlation with water temperature, will help in defining appropriate monitoring programs and post-harvest policies for this hazard, improving the management of the harvesting areas and the safety of bivalve molluscs.
authors.affiliation: Istituto Superiore di Sanità, Department of Veterinary Public Health and Food Safety, viale Regina Elena 299, 00161 Rome, Italy. Electronic address: elisabetta.suffredini@iss.it.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Suffredini
authors.affiliation: Istituto Zooprofilattico Sperimentale delle Venezie, viale Università 10, 35020 Legnaro, PD, Italy.
authors.forename: Renzo
authors.initials: R
authors.lastname: Mioni
authors.affiliation: University of Sassari, Department of Veterinary Medicine, via Vienna 2, 07100 Sassari, Italy.
authors.forename: Rina
authors.initials: R
authors.lastname: Mazzette
authors.affiliation: Istituto Zooprofilattico Sperimentale delle Venezie, viale Università 10, 35020 Legnaro, PD, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Bordin
authors.affiliation: University of Bologna, Department of Veterinary Medical Sciences, viale Vespucci 2, 47042 Cesenatico, FC, Italy.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Serratore
authors.affiliation: University of Sassari, Department of Veterinary Medicine, via Vienna 2, 07100 Sassari, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Fois
authors.affiliation: University of Bologna, Department of Veterinary Medical Sciences, viale Vespucci 2, 47042 Cesenatico, FC, Italy.
authors.forename: Annamaria
authors.initials: A
authors.lastname: Piano
authors.affiliation: Istituto Superiore di Sanità, Department of Veterinary Public Health and Food Safety, viale Regina Elena 299, 00161 Rome, Italy.
authors.forename: Loredana
authors.initials: L
authors.lastname: Cozzi
authors.affiliation: Istituto Superiore di Sanità, Department of Veterinary Public Health and Food Safety, viale Regina Elena 299, 00161 Rome, Italy.
authors.forename: Luciana
authors.initials: L
authors.lastname: Croci
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics; D004926:Escherichia coli / Q000302:isolation & purification; D005516:Food Microbiology; D007558:Italy; D012475:Salmonella / Q000302:isolation & purification; D012758:Shellfish / Q000382:microbiology*; D013234:Stem Cells; D013696:Temperature; D014157:Transcription Factors / Q000235:genetics; D014736:Vibrio parahaemolyticus / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D014157:Transcription Factors; C066719:toxR protein, bacteria
keywords: Colony hybridization; Quantitative analysis; Shellfish; Vibrio parahaemolyticus; tdh; trh