Polynucleotide phosphorylase has an impact on cell biology of Campylobacter jejuni

Polynucleotide phosphorylase (PNPase), encoded by the pnp gene, is known to degrade mRNA, mediating post-transcriptional regulation and may affect cellular functions. The role of PNPase is pleiotropic. As orthologs of the two major ribonucleases (RNase E and RNase II) of Escherichia coli are missing in the Campylobacter jejuni genome, in the current study the focus has been on the C. jejuni ortholog of PNPase. The effect of PNPase mutation on C. jejuni phenotypes and proteome was investigated. The inactivation of the pnp gene reduced significantly the ability of C. jejuni to adhere and to invade Ht-29 cells. Moreover, the pnp mutant strain exhibited a decrease in C. jejuni swimming ability and chick colonization. To explain effects of PNPase on C. jejuni 81-176 phenotype, the proteome of the pnp mutant and parental strains were compared. Overall, little variation in protein production was observed. Despite the predicted role of PNPase in mRNA regulation, the pnp mutation did not induce profound proteomic changes suggesting that other ribonucleases in C. jejuni might ensure this biological function in the absence of PNPase. Nevertheless, synthesis of proteins which are involved in virulence (LuxS, PEB3), motility (N-acetylneuraminic acid synthetase), stress-response (KatA, DnaK, Hsp90), and translation system (EF-Tu, EF-G) were modified in the pnp mutant strain suggesting a more specific role of PNPase in C. jejuni. In conclusion, PNPase deficiency induces limited but important consequences on C. jejuni biology that could explain swimming limitation, chick colonization delay, and the decrease of cell adhesion/invasion ability

Use of intranasal mupirocin to prevent methicillin-resistant Staphylococcus aureus infection in intensive care units

INTRODUCTION: Methicillin-resistant Staphylococcus aureus (MRSA) causes severe morbidity and mortality in intensive care units (ICUs) worldwide. The purpose of this study was to determine whether intranasal mupirocin prophylaxis is useful to prevent ICU-acquired infections with MRSA. MATERIALS AND METHODS: We conducted a 4-year observational retrospective study in a 15-bed adult medical ICU. During the first 2-year period mupirocin ointment was included in the MRSA control programme; during the second, mupirocin was not used. The main endpoint was the number of endogenous ICU-acquired infections with MRSA. RESULTS: The number of endogenous acquired infections was significantly higher during the second period than during the first (11 versus 1; P = 0.02), although there was no significant difference in the total number of patients infected with MRSA between the two periods. We also observed that nasal MRSA decolonisation was significantly higher in the mupirocin period than in mupirocin-free period (P = 0.002). CONCLUSION: Our findings suggest that intranasal mupirocin can prevent endogenous acquired MRSA infection in an ICU. Further double-blind, randomised, placebo-controlled studies are needed to demonstrate its cost-effectiveness and its impact on resistance

HACCP andfresh fish production : application in a marine farm

At the end of the nineties, the French marine farming industry was faced with new European regulations on food safety, recommending risk analysis and control based on HACCP (Hazard Analysis and Critical Control Point) guidelines. However, at the time, the marine farming industry had no good hygiene practice guidelines, and no index in French listing the hazards associated with fresh fish consumption. A marine farm then decided to apply the HACCP guidelines to its production, i.e. the growing of seabass (Dicentrarchus labrax) sold fresh, ungutted and shipped chilled on ice. This required a description of the product and production process, followed by a risk analysis contextualized to the company.A la fin des années 90, la filière aquacole marine se retrouve confrontée à la nouvelle approche réglementaire européenne en matière de sécurité des aliments, préconisant une analyse et une maîtrise des risques inspirées de la démarche HACCP (Analyse des Dangers avec Maîtrise des Points Sensibles). Cependant, la filière aquacole marine était dépourvue de guides de bonnes pratiques hygiéniques, ainsi que d'un répertoire synthétique, en français, des dangers liés à la consommation de poisson frais. C'est dans ce contexte qu'une ferme marine aquacole a souhaité appliquer la démarche HACCP à sa production : le grossissement de bars (Dicentrarchus labrax) vendus frais non éviscérés, expédiés sous glace. Cela supposait tout d'abord une description du produit et du procédé de production, puis une identification des dangers associés à la consommation de poissons, avant d'envisager l'analyse contextualisée à l'entreprise de ces dangers

Antimicrobial activity of Ti-ZrN/Ag coatings for use in biomaterial applications

Severely broken bones often require external bone fixation pins to provide support but they can become infected. In order to reduce such infections, novel solutions are required. Titanium zirconium nitride (Ti-ZrN) and Ti-ZrN silver (Ti-ZrN/Ag) coatings were deposited onto stainless steel. Surface microtopography demonstrated that on the silver containing surfaces, Sa and Sv values demonstrated similar trends whilst the Ra, average height and RMS value and Sp values increased with increasing silver concentration. On the Ti-ZrN/Ag coatings, surface hydrophobicity followed the same trend as the Sa and Sv values. An increase in dead Staphylococcus aureus and Staphylococcus epidermidis cells was observed on the coatings with a higher silver concentration. Using CTC staining, a significant increase in S. aureus respiration on the silver containing surfaces was observed in comparison to the stainless steel control whilst against S. epidermidis, no significant difference in viable cells was observed across the surfaces. Cytotoxicity testing revealed that the TiZrN coatings, both with and without varying silver concentrations, did not possess a detrimental effect to a human monocyte cell line U937. This work demonstrated that such coatings have the potential to reduce the viability of bacteria that result in pin tract infections

Survival of Campylobacter jejuni in mineral bottled water according to difference in mineral content: Application of the Weibull model

International audienceThe aim of the study was to examine the hypothesis proposed by Evans et al. [2003. Hazards of healthy living: bottled water and salad vegetables as risk factors for Campylobacter infection. Emerg. Infect. Dis. 9(10), 1219–1225] that mineral bottled water accidentally contaminated by Campylobacter jejuni would represent a risk factor for Campylobacter infection. Culturability of C. jejuni cells inoculated in low- and high-mineral bottled water during storage at 4 1C in the dark was performed by surface plating and modelled using theWeibull model. The loss of C. jejuni culturability observed in all conditions tested was shown to be dependent on strain, preculture condition and water composition. Following inoculation of C. jejuni, the rapid loss of culturability was not correlated to complete cell death as the passage into embryonated eggs enabled recovery of cells from the viable but non-culturable state. In conclusion, the sanitary risk associated with contaminated bottled water cannot be excluded although it is presumably low. Culture conditions, strain and water type must be taken into account in the evaluation of the risk factors as they influence significantly Campylobacter survival in water

La consommation de viande et les dangers biologiques

Bien souvent ressentie comme un plaisir par l’amateur de viande, la consommation de la chair des animaux de boucherie peut parfois être à l’origine d’une transmission d’agents biologiques pathogènes au consommateur. Ce chapitre a pour objectif de présenter l’ensemble de ces dangers leurs caractéristiques, leurs voies de contamination, et les grands moyens de maîtrise qui leur sont associés.</jats:p

Facteurs de risque de saisie en abattoir pour sarcosporidiose chez les bovins (étude en région Pays de la Loire)

De janvier 2003 à décembre 2008, 654 bovins ont donné lieu à une indemnisation à partir du Fond d Assainissement Régional (F.A.R.) suite à leur saisie pour sarcosporidiose dans l un des 13 abattoirs ligériens. La prévalence de ces saisies en région Pays de la Loire a ainsi été estimée à 0,304 , pour un coût d indemnisation annuel moyen de 89 000 EUR. L analyse des 102 réponses obtenues à un questionnaire envoyé par courrier dans 418 élevages cotisant au F.A.R. a mis en évidence que la majorité des bovins saisis étaient issus d élevages présentant des pratiques favorables au maintien des cycles évolutifs des Sarcocystis pouvant les infecter, sans pour autant définir ces pratiques comme facteurs de risque de saisie pour sarcosporidiose, en raison de l absence de population témoin. En parallèle, le traitement des données relatives aux 654 bovins saisis par le biais de régressions logistiques, a suggéré l existence de facteurs de prédisposition à ces saisies avec d une part un facteur sexe : les femelles sont ainsi environ 5 fois plus à risque que les mâles ; et d autre part un facteur race avec une apparente résistance de la race Charolaise, contrairement aux races Blonde d Aquitaine et dans une moindre mesure Limousine, qui sont en comparaison, respectivement 8 fois et 3 fois plus à risque vis-à-vis de ces saisies.TOULOUSE-EN Vétérinaire (315552301) / SudocNANTES-Ecole Nat.Vétérinaire (441092302) / SudocSudocFranceF

ETUDE DESCRIPTIVE ET CRITIQUE DE LA REGLEMENTATION CONCERNANT LA RECHERCHE DE TRICHINES EN FRANCE

NANTES-Ecole Nat.Vétérinaire (441092302) / SudocSudocFranceF