Carmen Candel-Perez
Universidad de Murcia, Spain
Title: Occurrence of Clostridium difficile in edible bivalve molluscs in Spain
Biography
Biography: Carmen Candel-Perez
Abstract
Statement of the Problem: Bivalve molluscs are a frequent source of viral and bacterial pathogens due to, among other factors, their filtering nature. Toxigenic C. difficile has been isolated from seafood samples with potential implications of transfer to humans.
Purpose: The purpose of this study is to assess the occurrence of C. difficile as well as bacterial indicators (Salmonella spp, Escherichia coli and reducers) in edible bivalve molluscs in Spain.
Methodology & Theoretical Orientation: A total of 129 samples, consisting in 123 samples of mussels (Mytilus galloprovincialis) and 6 oysters (Crassostrea cornucopiae), were purchased from outlets in the city of Murcia (southeast Spain). The isolation of C. difficile strains was carried out using enrichment broth suplemented with sodium taurocholate followed by etanol shock, prior to the culture on a selective media. The identification was carried out detecting Tpi gene using molecular techniques. The isolation and enumeration of bacterial indicators were investigated according to the ISO norm.
Findings: C. difficile was isolated from 8.94% (11/123) of the mussels investigated, what supposes 20.8% (5/24) from Mediterranean Sea and 6.45% (6/93) from Northwest Atlantic. No C. difficile was detected in modified atmosphere packs or in cooked mussels. All oysters samples were negative for C. difficile. About the associated flora, Clostridium sulphite reducers appeared in 31% (40/129) of the analysed samples and E. coli appeared in 1.5% (2/129). Salmonella spp. was not present in any sample. These bacterial indicators were in accordance with the current legal requirements.
Conclusion & Significance: These findings indicate that edible bivalve molluscs could be a potential source of C. difficile, with a slightly higher isolation rates than other studies. The intake of raw or poorly cooked contaminated bivalve molluscs with its spores could represent a risk for human health.