250 research outputs found
Modelling the exposure to Cronobacter sakazakii by consumption of a cocoa-milk-based beverage processed by pulsed electric fields
peer-reviewedM.C. Pina-PĂ©rez is grateful to CSIC for providing a DOCTOR contract linked to the INNPACTO project IPT-2011-1724-060000. This study was carried out with funds from BISOSTAD project PSE-060000-2009-003, Generalitat Valenciana I+D+I emergent research groups GV/2010/064 and CYCIT project AGL2010-22206-C02-01.Infantsâ exposure (Nf ) to Cronobacter sakazakii via the consumption of infant-rich-inpolyphenols
cocoa-milk-based beverages (CCX-M) treated with high-intensity pulsed
electric fields (PEF) was evaluated. Monte Carlo simulation enabled the prediction
of the variability in C. sakazakii load in beverages at the time of consumption to be
estimated. Different scenarios (initial contamination levels; PEF treatment conditions;
and time-temperature combinations of CCX-M beverages storage after treatment) were
simulated. Cocoa addition and PEF treatment resulted in the most influential input
factors to control bacterial final load. Cronobacter spp. exposure risk was reduced by
a maximum of 100 times at 95% of iterations due to addition of cocoa at 5 g/100 mL,
corresponding to scenario 3 (PEF: 15 kV/cmâ3,000 ÎŒs; storage 120 h at 8 °C). Moreover,
the probability of illness for a healthy population was reduced from 2.15 Ă 10-8,
in the baseline scenario, to 4.78 Ă 10-10 due to cocoa addition and application of
15 kV/cmâ3,000 ÎŒs PEF treatment.BISOSTAD projec
Cancers cutanĂ©s et bronchopulmonaire chez un viticulteur aprĂšs expositions rĂ©pĂ©tĂ©es Ă lâarsĂ©nite de soude
Lâarsenic est un mĂ©talloĂŻde dont les composĂ©s inorganiques solubles ont une toxicitĂ© Ă©levĂ©e. LâarsĂ©nite de soude, composĂ© arsenical inorganique Ă lâĂ©tat trivalent, a Ă©tĂ© utilisĂ© jusquâen 2001 comme antifongique en viticulture française. Il a Ă©tĂ© classĂ© dans le groupe des agents cancĂ©rogĂšnes avĂ©rĂ©s par le Centre international de recherche sur le cancer (CIRC) dĂšs 1979. Il nâexiste aucune substitution efficiente actuellement.Le cas rapportĂ© relate lâhistoire dâun homme ĂągĂ© de 62 ans, ouvrier viticole retraitĂ©, fumeur, exposĂ© Ă lâarsĂ©nite de soude (dont le PyralescaÂź identifiĂ© sur les factures du chef dâentreprise). Il a Ă©tĂ© atteint de kĂ©ratoses actiniques profuses, et de plusieurs carcinomes Ă©pidermoĂŻdes dĂšs le dĂ©but des annĂ©es 80, puis opĂ©rĂ© (pneumonectomie gauche) dâun carcinome bronchique Ă©pidermoĂŻde lobaire infĂ©rieur gauche (pT4N1 Mx) en 2006. Ces deux localisations cancĂ©reuses sont imputables Ă lâutilisation dâarsĂ©nite de soude par prĂ©somption dâorigine. Elles ont Ă©tĂ© reconnues courant 2009, en maladies professionnelles indemnisables du rĂ©gime agricole. En raison du long dĂ©lai dâapparition des cancers aprĂšs expositions arsenicales, des cas peuvent toujours apparaĂźtre, a posteriori, chez des salariĂ©s en activitĂ©, ou retraitĂ©s. Bien quâun risque dâintoxication aiguĂ« subsiste du fait de restes de stock, la possibilitĂ© dâune exposition chronique Ă lâarsĂ©nite en viticulture est improbable en France depuis la campagne dâĂ©radication de 2006â2007 oĂč 97 % des stocks ont Ă©tĂ© traitĂ©s. Une information reste nĂ©anmoins nĂ©cessaire auprĂšs des mĂ©decins du travail, mĂ©decins gĂ©nĂ©ralistes, dermatologues et pneumologues afin de lutter contre la sous-dĂ©claration de ce type de cancers professionnels. Enfin, un suivi post-professionnel pourrait ĂȘtre envisagĂ© en rĂ©gime agricole
Impact of etiology leading to abdominoperineal resection with anterolateral thigh flap reconstruction: A retrospective cohort study.
Large and deep perineal defects following abdominal perineal resection (APR) are a challenge for reconstructive surgeons. Even if generally performed for oncological reasons, APR can be indicated as well in extended infection-related debridement for Hidradenitis suppurativa, Fournier's gangrene, or Crohn's disease. We aimed to compare the outcomes of two groups of patients with different indications for APR (infectious vs. oncological) after pedicled anterolateral thigh (ALT) flap coverage RESULTS: Forty-four consecutive pedicled ALT flap used for coverage after APR in 40 patients were analyzed. Twenty-seven patients (67.5%) underwent APR for oncological reasons and 13 patients (32.5%) for infectious reasons. The overall postoperative complications rate was significantly higher for infectious cases (76.5% vs. 40.7%, p = 0.0304). Major complications occurred in 52.9% of infectious cases versus 11.1% of oncological cases (p = 0.0045). Obesity and infectious etiology were independent risk factors for overall and major complications, respectively.
Patients undergoing APR for acute or chronic infections had significantly more overall and major complications than patients having oncological APR. Modified care might be considered, especially in obese patients, in terms of surgical debridement, antibiotic treatment modalities, and postoperative management
Prédiction des transferts et de la croissance microbienne lors du transport de carcasses de porcs
26eme congrÚs français de thermique, Pau, FRA, 29-/05/2018 - 01/06/2018National audienceLors du transport de carcasses de porcs, plusieurs facteurs influencent l'évolution de la charge microbienne notamment la température et l'activité de l'eau qui dépendent des transferts dechaleur et d'eau au sein et autour des carcasses. Une expérimentation a été réalisée sur une maquette à l'échelle ~1/3 d'un camion frigorifique chargé de carcasses pour déterminer l'hétérogénéité des coefficients de transfert. Un modÚle a ensuite été développé pour simuler les transferts de chaleur et dematiÚre au niveau du jambon de la carcasse. Enfin, ce modÚle de transfert a été couplé à un modÚle de microbiologie prédictive
The porin and the permeating antibiotic: A selective diffusion barrier in gram-negative bacteria
Gram-negative bacteria are responsible for a large proportion of antibiotic resistant bacterial diseases. These bacteria have a complex cell envelope that comprises an outer membrane and an inner membrane that delimit the periplasm. The outer membrane contains various protein channels, called porins, which are involved in the influx of various compounds, including several classes of antibiotics. Bacterial adaptation to reduce influx through porins is an increasing problem worldwide that contributes, together with efflux systems, to the emergence and dissemination of antibiotic resistance. An exciting challenge is to decipher the genetic and molecular basis of membrane impermeability as a bacterial resistance mechanism. This Review outlines the bacterial response towards antibiotic stress on altered membrane permeability and discusses recent advances in molecular approaches that are improving our knowledge of the physico-chemical parameters that govern the translocation of antibiotics through porin channel
Reversal of the ÎdegP Phenotypes by a Novel rpoE Allele of Escherichia coli
RseA sequesters RpoE (ÏE) to the inner membrane of Escherichia coli when envelope stress is low. Elevated envelope stress triggers RseA cleavage by the sequential action of two membrane proteases, DegS and RseP, releasing ÏE to activate an envelope stress reducing pathway. Revertants of a ÎdegP ÎbamB strain, which fails to grow at 37°C due to high envelope stress, harbored mutations in the rseA and rpoE genes. Null and missense rseA mutations constitutively hyper-activated the ÏE regulon and significantly reduced the major outer membrane protein (OMP) levels. In contrast, a novel rpoE allele, rpoE3, resulting from the partial duplication of the rpoE gene, increased ÏE levels greater than that seen in the rseA mutant background but did not reduce OMP levels. A ÏE-dependent RybB::LacZ construct showed only a weak activation of the ÏE pathway by rpoE3. Despite this, rpoE3 fully reversed the growth and envelope vesiculation phenotypes of ÎdegP. Interestingly, rpoE3 also brought down the modestly activated Cpx envelope stress pathway in the ÎdegP strain to the wild type level, showing the complementary nature of the ÏE and Cpx pathways. Through employing a labile mutant periplasmic protein, AcrAL222Q, it was determined that the rpoE3 mutation overcomes the ÎdegP phenotypes, in part, by activating a ÏE-dependent proteolytic pathway. Our data suggest that a reduction in the OMP levels is not intrinsic to the ÏE-mediated mechanism of lowering envelope stress. They also suggest that under extreme envelope stress, a tight homeostasis loop between RseA and ÏE may partly be responsible for cell death, and this loop can be broken by mutations that either lower RseA activity or increase ÏE levels
Two Seemingly Homologous Noncoding RNAs Act Hierarchically to Activate glmS mRNA Translation
Small noncoding RNAs (sRNA) can function as posttranscriptional activators of gene expression to regulate stress responses and metabolism. We here describe the mechanisms by which two sRNAs, GlmY and GlmZ, activate the Escherichia coli glmS mRNA, coding for an essential enzyme in amino-sugar metabolism. The two sRNAs, although being highly similar in sequence and structure, act in a hierarchical manner. GlmZ, together with the RNA chaperone, Hfq, directly activates glmS mRNA translation by an anti-antisense mechanism. In contrast, GlmY acts upstream of GlmZ and positively regulates glmS by antagonizing GlmZ RNA inactivation. We also report the first example, to our knowledge, of mRNA expression being controlled by the poly(A) status of a chromosomally encoded sRNA. We show that in wild-type cells, GlmY RNA is unstable due to 3âČ end polyadenylation; whereas in an E. coli pcnB mutant defective in RNA polyadenylation, GlmY is stabilized and accumulates, which in turn stabilizes GlmZ and causes GlmS overproduction. Our study reveals hierarchical action of two well-conserved sRNAs in a complex regulatory cascade that controls the glmS mRNA. Similar cascades of noncoding RNA regulators may operate in other organisms
Antibiotic Stress, Genetic Response and Altered Permeability of E. coli
BACKGROUND: Membrane permeability is the first step involved in resistance of bacteria to an antibiotic. The number and activity of efflux pumps and outer membrane proteins that constitute porins play major roles in the definition of intrinsic resistance in Gram-negative bacteria that is altered under antibiotic exposure. METHODOLOGY/PRINCIPAL FINDINGS: Here we describe the genetic regulation of porins and efflux pumps of Escherichia coli during prolonged exposure to increasing concentrations of tetracycline and demonstrate, with the aid of quantitative real-time reverse transcriptase-polymerase chain reaction methodology and western blot detection, the sequence order of genetic expression of regulatory genes, their relationship to each other, and the ensuing increased activity of genes that code for transporter proteins of efflux pumps and down-regulation of porin expression. CONCLUSIONS/SIGNIFICANCE: This study demonstrates that, in addition to the transcriptional regulation of genes coding for membrane proteins, the post-translational regulation of proteins involved in the permeability of Gram-negative bacteria also plays a major role in the physiological adaptation to antibiotic exposure. A model is presented that summarizes events during the physiological adaptation of E. coli to tetracycline exposure
The steeply subducting edge of the Cocos Ridge : evidence from receiver functions beneath the northern Talamanca Range, south-central Costa Rica
The deep structure of the south-central Costa Rican subduction zone has not been studied in great detail so far because large parts of the area are virtually inaccessible. We present a receiver function study along a transect of broadband seismometers through the northern flank of the Cordillera de Talamanca (south Costa Rica). Below Moho depths, the receiver functions image a dipping positive conversion signal. This is interpreted as the subducting Cocos Plate slab, compatible with the conversions in the individual receiver functions. In finite difference modeling, a dipping signal such as the one imaged can only be reproduced by a steeply (80°) dipping structure present at least until a depth of about 70â100 km; below this depth, the length of the slab cannot be determined because of possible scattering effects. The proposed position of the slab agrees with previous results from local seismicity, local earthquake tomography, and active seismic studies, while extending the slab location to greater depths and steeper dip angle. Along the trench, no marked change is observed in the receiver functions, suggesting that the steeply dipping slab continues until the northern flank of the Cordillera de Talamanca, in the transition region between the incoming seamount segment and Cocos Ridge. Considering the time predicted for the establishment of shallow angle underthrusting after the onset of ridge collision, the southern Costa Rican subduction zone may at present be undergoing a reconfiguration of subduction style, where the transition to shallow underthrusting may be underway but still incomplete
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