Yersinia enterocolitica prevalence and diversity in a pig slaughterhouse

Yersinia enterocolitica is involved in human foodborne infections. Pigs are considered as a major reservoir in many countries. The aim of the study was to contribute to the evaluation of the prevalence of Y. enterocolitica in France in pigs at the slaughterhouse level with optimized detection methods based on ISO 10273-2003

Yersinia enteroco/itica prevalence in a French slaughterhouse: first results

Yersinlia enterocolitica is involved in human foodbome infections. Pigs are considered as a major reservoir in many countries. The aim of the study was to contribute to the evaluation of the prevalence of Y. enterocolitica in France in pigs at the slaughterhouse level with optimized detection methods based on ISO 10273-2003. Several samples of tonsils over nine consecutive months were analyzed in a single slaughterhouse. Enumeration and isolation were achieved by using CIN agar and Y eCM chromogenic medium (modified from the Weagant medium, 2008). Two enrichment media were used: a peptone, sorbitol and biliary salts broth (PSB) and the Irgasan, Ticarcillin and potassium chlorate broth (ITC)

Characterization of Ceftazidime Resistance Mechanisms in Clinical Isolates of Burkholderia pseudomallei from Australia

Burkholderia pseudomallei is a Gram-negative bacterium that causes the serious human disease, melioidosis. There is no vaccine against melioidosis and it can be fatal if not treated with a specific antibiotic regimen, which typically includes the third-generation cephalosporin, ceftazidime (CAZ). There have been several resistance mechanisms described for B. pseudomallei, of which the best described are amino acid changes that alter substrate specificity in the highly conserved class A β-lactamase, PenA. In the current study, we sequenced penA from isolates sequentially derived from two melioidosis patients with wild-type (1.5 µg/mL) and, subsequently, resistant (16 or ≥256 µg/mL) CAZ phenotypes. We identified two single-nucleotide polymorphisms (SNPs) that directly increased CAZ hydrolysis. One SNP caused an amino acid substitution (C69Y) near the active site of PenA, whereas a second novel SNP was found within the penA promoter region. In both instances, the CAZ resistance phenotype corresponded directly with the SNP genotype. Interestingly, these SNPs appeared after infection and under selection from CAZ chemotherapy. Through heterologous cloning and expression, and subsequent allelic exchange in the native bacterium, we confirmed the role of penA in generating both low-level and high-level CAZ resistance in these clinical isolates. Similar to previous studies, the amino acid substitution altered substrate specificity to other β-lactams, suggesting a potential fitness cost associated with this mutation, a finding that could be exploited to improve therapeutic outcomes in patients harboring CAZ resistant B. pseudomallei. Our study is the first to functionally characterize CAZ resistance in clinical isolates of B. pseudomallei and to provide proven and clinically relevant signatures for monitoring the development of antibiotic resistance in this important pathogen

Yersinia enterocolitica prevalence and diversity in a pig slaughterhouse

Yersinia enterocolitica is involved in human foodborne infections. Pigs are considered as a major reservoir in many countries. The aim of the study was to contribute to the evaluation of the prevalence of Y. enterocolitica in France in pigs at the slaughterhouse level with optimized detection methods based on ISO 10273-2003.</p

Yersinia enteroco/itica prevalence in a French slaughterhouse: first results

Yersinlia enterocolitica is involved in human foodbome infections. Pigs are considered as a major reservoir in many countries. The aim of the study was to contribute to the evaluation of the prevalence of Y. enterocolitica in France in pigs at the slaughterhouse level with optimized detection methods based on ISO 10273-2003. Several samples of tonsils over nine consecutive months were analyzed in a single slaughterhouse. Enumeration and isolation were achieved by using CIN agar and Y eCM chromogenic medium (modified from the Weagant medium, 2008). Two enrichment media were used: a peptone, sorbitol and biliary salts broth (PSB) and the Irgasan, Ticarcillin and potassium chlorate broth (ITC).</p

Quels sont les impacts de conditions abiotiques sur la croissance cellulaire de deux pathogènes alimentaires Listeria monocytogenes et Escherichia coli 0157:H7 ?

International audienc

Evaluation de la qualité et de la sécurité des produits prêt-à consommer à base de porc dans la chaîne du froid.

International audienceIt is of crucial importance for Ready-To-Eat (RTE) foodstuffs producers to guarantee the quality and safety of their products under the cold chain variations related to different time–temperature profiles. Experimental designs were used to investigate and model the effects of temperature on safety and quality attributes of selected RTE meat products. Three types of RTE sliced pork products (cooked ham, cooked paté and smoked ham) were stored at different temperatures (5, 8, 12 and 15 C) up to 6 weeks. Microbiological and physico-chemical attributes were followed. Growth parameters of Listeria monocytogenes were investigated by challenge testing for the three RTE products at the four temperatures. Two lactic acid bacteria (Lactobacillus sakei and Leuconostoc mesenteroïdes) were also investigated by challenge testing but only for cooked ham and cooked paté at 8 C. Changes in quality indicators including colour, texture and water content, water activity and water dripping were evaluated over storage time for the three RTE products. Spoilage experiments were conducted (at 2, 8, 12, 15 C for 48 days) on cooked ham and the production of ethanol, as a representative volatile deriving from bacterial metabolism, was correlated to bacterial outgrowth. Growth parameters of the three strains for the given food were mathematically modelled and validation tests were performed for L. monocytogenes in cooked ham and cooked paté. Physico-chemical attributes were not significantly affected by time–temperature storage. The production of ethanol on spoiled cooked ham was related to growth of lactic acid bacteria, especially Leuconostoc. A threshold value of ethanol concentration was defined in relation with a threshold count numbers of LAB under the conditions studied

How the cold chain impacts the shelf life of a ready-to-eat food regarding listeria monocytogenes

2nd IIR International conference on Sustainability and the Cold Chain, ICCC2013, Paris, FRA, 02-/04/2013 - 04/04/2013International audienceFor RTE foods that are able to support the growth of L. monocytogenes, a European Regulation (n°2073/2005) specifies that the 100-CFU/g limit &amp;#8220;applies if the manufacturer is able to demonstrate that the product will not exceed the limit of 100 CFU/g throughout the shelf-life&amp;#8221;. Many factors can interfere on the evolution of the pathogen (time-temperature history, pH, aw, associated microflora,...). The objective of this work was to demonstrate the impact of the cold chain on the shelf-life of a deli meat, sliced cooked ham. Sliced cooked ham data were obtained from challenge-tests with artificially inoculated packages with L. monocytogenes. These data are useful for estimating growth parameters and model validation. We tested different scenarios of storage temperature: from theoretical to more realistic scenarios based on data from a survey carried out in France. The variability of temperatures as well as characteristics of the product, and initial contamination level at the end of the manufacturing line, were taken into account in predictive models to calculate the time to reach the regulatory limit and to determine the shelf life. We showed that shelf-life determination is strongly dependant of the scenario chosen to simulate the cold chain

Effect of ball-milling and Fe-/Al-doping on the structural aspect and visible light photocatalytic activity of TiO2 towards Escherichia coli bacteria abatement

Escherichia coil abatement was studied in liquid phase under visible light in the presence of two commercial titania photocatalysts, and of Fe- and Al-doped titania samples prepared by high energy ball-milling. The two commercial titania photocatalysts, Aeroxide P25 (Evonik industries) exhibiting both rutile and anatase structures and MPT625 (Ishihara Sangyo Kaisha), a Fe-, Al-, P- and S-doped titania exhibiting only the rutile phase, are active suggesting that neither the structure nor the doping is the driving parameter. Although the MPT625 UV-visible spectrum is shifted towards the visible domain with respect to the P25 one, the effect on bacteria is not increased. On the other hand, the ball milled iron-doped P25 samples exhibit low activities in bacteria abatement under visible light due to charge recombinations unfavorable to catalysis as shown by photoluminescence measurements. While doping elements are in interstitial positions within the rutile structure in MPT625 sample, they are located at the surface in ball milled samples and in isolated octahedral units according to Fe-57 Mossbauer spectrometry. The location of doping elements at the surface is suggested to be responsible for the sample cytotoxicity observed in the dark. (C) 2014 Elsevier B.V. All rights reserved