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Unlabelled: Although little evidence existed to support that view, European countries and in particular France, have regarded echinoderms, including sea urchins, as low risk in terms of feacal contamination. It is hypothesized that the sea urchins mode of feeding, which is based on grazing and differs from bivalve molluscs, would prevent it from concentrating high levels of Escherichia coli. Here, we monitored E. coli levels in sea urchins (Paracentrotus lividus) and in filter-feeder mussels (Mytillus galloprovincialis), collected concurrently from the same natural area over a 1-year period to verify this assumption. Sea urchins were collected on the seafloor, whereas mussels were collected from the water column at a depth of 4 m. Our results showed heavy bacterial loading of sea urchins in a natural growing environment. Moreover, we highlighted that E. coli contamination of sea urchins could, in certain conditions, be higher than those detected in filter-feeding mussels collected at the same location. Finally, the results showed a significant correlation between rainfall and E. coli concentrations in sea urchins, suggesting that the bacterial safety of sea urchin could be linked to the quality of the surrounding water., Significance and Impact of the Study: The European regulation requires competent authorities to monitor the sanitary status of shellfish, including live echinoderms, through faecal indicator organisms. In the French Mediterranean, sea urchin production is significant. Until now, as no data showed significant E. coli contamination levels, no monitoring programs focused on this species. This study demonstrates that sea urchins are more vulnerable to faecal contamination than previously hypothesized, especially during heavy rainfall. In consequence, the European authority general approach to microbiological management of shellfish should be applied to sea urchins., (© 2015 The Society for Applied Microbiology.)

In order to assess the putative toxigenic risk associated with the presence of fungal strains in shellfish-farming areas, Penicillium strains were isolated from bivalve molluscs and from the surrounding environment, and the influence of the sample origin on the cytotoxicity of the extracts was evaluated. Extracts obtained from shellfish-derived Penicillia exhibited higher cytotoxicity than the others. Ten of these strains were grown on various media including a medium based on mussel extract (Mytilus edulis), mussel flesh-based medium (MES), to study the influence of the mussel flesh on the production of cytotoxic compounds. The MES host-derived medium was created substituting the yeast extract of YES medium by an aqueous extract of mussel tissues, with other constituent identical to YES medium. When shellfish-derived strains of fungi were grown on MES medium, extracts were found to be more cytotoxic than on the YES medium for some of the strains. HPLC-UV/DAD-MS/MS dereplication of extracts from Penicillium marinum and P. restrictum strains grown on MES medium showed the enhancement of the production of some cytotoxic compounds. The mycotoxin patulin was detected in some P. antarcticum extracts, and its presence seemed to be related to their cytotoxicity. Thus, the enhancement of the toxicity of extracts obtained from shellfish-derived Penicillium strains grown on a host-derived medium, and the production of metabolites such as patulin suggests that a survey of mycotoxins in edible shellfish should be considered., (© 2013 The Society for Applied Microbiology.)

Aims: To investigate the antimicrobial spectrum of Lactococcus piscium CNCM I-4031 and its protective effect in cooked and peeled shrimp against Brochothrix thermosphacta., Methods and Results: Sixteen pathogenic and spoiling bacteria were inhibited in Elliker, but not in shrimp juice agar plates. In shrimp packed under modified atmosphere and stored at 8 degrees C, B. thermosphacta (10(3) CFU g(-1)) was inhibited by 4.1 log CFU g(-1) when co-inoculated with L. piscium (10(6) CFU g(-1)). Brochothrix thermosphacta spoiled the product after 11 days, with the emission of strong butter/caramel off-odours. In co-culture with L. piscium, sensory shelf-life was extended by at least 10 days. The inhibition was partially explained by a drop in pH from 6.6 to 5.6. The physicochemical composition of shrimp and shrimp juice was established to identify the inhibition mechanisms involved., Conclusion: Lactococcus piscium CNCM I-4031 has a wide antimicrobial spectrum. The strain inhibits B. thermosphacta in shrimp and significantly prolongs sensory shelf-life., Significance and Impact of the Study: Lactococcus piscium CNCM I-4031 is shown to be a promising agent for improving shrimp quality and may be tested against pathogens and in other food matrices. Knowledge of the physicochemical composition of shrimp and shrimp juice will allow the development of a chemically defined model medium for determining the inhibition mechanisms involved.

Aims: To develop a method to screen antifouling agents against marine bacterial adhesion as a sensitive, rapid and quantitative microplate fluorescent test., Methods and Results: Our experimental method is based on a natural biofilm formed by mono-incubation of the marine bacterium Pseudoalteromonas sp. D41 in sterile natural sea water in a 96-well polystyrene microplate. The 4'6-diamidino-2-phenylindole dye was used to quantify adhered bacteria in each well. The total measured fluorescence in the wells was correlated with the amount of bacteria showing a detection limit of one bacterium per 5 microm(2) and quantifying 2 x 10(7) to 2 x 10(8) bacteria adhered per cm(2). The antifouling properties of three commercial surface-active agents and chlorine were tested by this method in the prevention of adhesion and also in the detachment of already adhered bacteria. The marine bacterial adhesion inhibition rate depending on the agent concentration showed a sigmoid shaped dose-response curve., Conclusions: This test is well adapted for a rapid and quantitative first screening of antifouling agents directly in seawater in the early steps of marine biofilm formation., Significance and Impact of the Study: In contrast to the usual screenings of antifouling products which detect a bactericidal activity, this test is more appropriate to screen antifouling agents for bacterial adhesion removal or bacterial adhesion inhibition activities. This screening test focuses on the antifouling properties of the products, especially the initial steps of marine biofilm formation.

An original magnetic beads RNA capture was developed for the detection of Norwalk-like virus by RT-PCR. The same oligonucleotide was used both for capture and reverse transcription of the viral RNA. The optimization studies showed that the most important parameter for sensitivity is the biotin-binding capacity of the beads. This method was found to be efficient for eliminating inhibitors in sewage samples compared with the classic RT-PCR. Moreover, the sensitivity was greatly enhanced, allowing the detection of 42% positive sample after gel electrophoresis, which is fourfold greater than classic RT-PCR (11%). Beads-RT-PCR sensitivity is the same as classic RT-PCR and hybridization. Thus, this method, which is easy to perform, should be of particular interest for developing quantitative RT-PCR and sequencing.