Experimental evidence that polystyrene nanoplastics cross the intestinal barrier of European seabass.

Plastic pollution in marine ecosystems constitutes an important threat to marine life. For vertebrates, macro/microplastics can obstruct and/or transit into the airways and digestive tract whereas nanoplastics (NPs; < 1000 nm) have been observed in non-digestive tissues such as the liver and brain. Whether NPs cross the intestinal epithelium to gain access to the blood and internal organs remains controversial, however. Here, we show directly NP translocation across the intestinal barrier of a fish, the European seabass, Dicentrarchus labrax, ex vivo. The luminal side of median and distal segments of intestine were exposed to fluorescent polystyrene NPs (PS-NPs) of 50 nm diameter. PS-NPs that translocated to the serosal side were then detected quantitatively by fluorimetry, and qualitatively by scanning electron microscopy (SEM) and pyrolysis coupled to gas chromatography and high-resolution mass spectrometry (Py-GC-HRMS). Fluorescence intensity on the serosal side increased 15-90 min after PS-NP addition into the luminal side, suggesting that PS-NPs crossed the intestinal barrier; this was confirmed by both SEM and Py-GC-HRMS. This study thus evidenced conclusively that NPs beads translocate across the intestinal epithelium in this marine vertebrate.

[Study of the reproducibility of the sterilization process and proposal of an sterilizer requalification protocol]. / Étude de la reproductibilité du procédé de stérilisation et proposition d'un protocole de requalification des stérilisateurs.

Unlike EN 554, and since the publication of ISO 17665-1 standard, the user of autoclaves may use methods other than those indicated in the guidelines. Outsourcing the requalification of sterilizers by an external service provider and after observing from the previous requalification reports that the thermometric data seemed reproducible, we decided to propose and validate a validation method for the reproducibility of the sterilization process. This is to exempt from the study of the repeatability of the EN 554 standard in future requalifications. Reproducibility was studied with the sensors of the sterilization service and from the production cycles. This study was carried out in three parts. First, we checked whether our sensors were reliable. Then we evaluated the sterilization process fidelity of each sterilizer. Finally, we compared our measurements performed by the service sensors with the measurements performed by the service provider during the requalifications of the previous years. This work leads us to describe a new protocol of requalification of our sterilizers.

[Development and validation of an analytical method to quantify residues of cleaning products able to inactivate prion]. / Développement et validation d'une méthode de dosage des traces de détergents inactivants totaux du prion.

OBJECTIVES: In this study, a novel analytical method to quantify prion inactivating detergent in rinsing waters coming from the washer-disinfector of a hospital sterilization unit has been developed. The final aim was to obtain an easy and functional method in a routine hospital process which does not need the cleaning product manufacturer services. METHODS: An ICP-MS method based on the potassium dosage of the washer-disinfector's rinsing waters was developed. Potassium hydroxide is present on the composition of the three prion inactivating detergent currently on the French market. The detergent used in this study was the Actanios LDI(®) (Anios laboratories). A Passing and Bablok regression compares concentrations measured with this developed method and with the HPLC-UV manufacturer method. RESULTS: According to results obtained, the developed method is easy to use in a routine hospital process. The Passing and Bablok regression showed that there is no statistical difference between the two analytical methods during the second rinsing step. Besides, both methods were linear on the third rinsing step, with a 1.5ppm difference between the concentrations measured for each method. CONCLUSIONS: This study shows that the ICP-MS method developed is nonspecific for the detergent, but specific for the potassium element which is present in all prion inactivating detergent currently on the French market. This method should be functional for all the prion inactivating detergent containing potassium, if the sensibility of the method is sufficient when the potassium concentration is very low in the prion inactivating detergent formulation.

Phenotypic and genotypic characterization of H2 S-positive and H2 S-negative strains of Shewanella baltica isolated from spoiled whiting (Merlangius merlangus).

UNLABELLED: Four strains were isolated from a spoiled whiting (Merlangius merlangus). All of them were able to grow aerobically from 4 to 30°C and also able to develop anaerobically in the presence of trimethylamine N-Oxide (TMAO) at 25°C. Biochemical characterization did not allow identification of the strains species but showed that one of the four strains was unable to produce H2 S. Two strains synthetized an ornithine decarboxylase being potential putrescine producers. Results of carbon source use highlighted that the four strains were able to use citrate and d-sucrose and one strain was not able to use l-arabinose. Genotypic characterization of the strains thanks to 16S rRNA and gyrB partial gene sequencing led to their identification as members of Shewanella baltica species. These observations suggest that H2 S production may not be the most appropriate screening parameter for Shewanella species and further to monitor the development of spoilage flora. SIGNIFICANCE AND IMPACT OF THE STUDY: Shewanella is a complex genus composed of numerous and heterogeneous species. One of them Shewanella baltica has previously been described as one of the most important H2 S-producing bacterial species in iced stored fish and may act as spoilage organism through the reduction of trimethylamine N-Oxide (TMAO). Four strains of S. baltica were isolated from spoiled whiting (Merlangius merlangus), and description of three H2 S-positive strains and one H2 S-negative strain of S. baltica is highlighted in this short paper. Consequently, H2 S production might not be the most appropriate screening parameter to assess the development of spoilage organisms.