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61.
Identification and antimicrobial susceptibility of 100 Klebsiella animal clinical isolates 总被引:1,自引:0,他引:1
The objectives of this study were to determine the distribution of Klebsiella species and phylogenetic groups in animal clinical samples and to determine the levels of antimicrobial resistance of animal Klebsiella clinical isolates. One hundred Klebsiella veterinary clinical isolates were identified using gyrA PCR-RFLP and rpoB gene sequencing as a confirmatory method. Klebsiella pneumoniae phylogenetic group KpI was dominant (78 isolates), but KpII, KpIII (K. variicola), K. oxytoca, K. planticola and K. terrigena were also represented. The relative frequencies in animal infections of Klebsiella species and phylogenetic groups were similar to those observed in human nosocomial infections, suggesting that similar ecological and molecular factors cause Klebsiella infections in both situations. Resistance was common against ampicillin (99%) and cephalexin (43%) but not against ceftazidime, ceftiofur, tetracycline, enrofloxacin, gentamicin and trimethoprim-sulfamethoxazole. Thirteen isolates resistant to three or more antimicrobials or combinations thereof were found, but acquired antimicrobial resistance remains lower among animal isolates than among human nosocomial isolates. 相似文献
62.
Effectiveness of steam pasteurization in controlling microbiological hazards of cull cow carcasses in a commercial plant 下载免费PDF全文
Harold Corantin Sylvain Quessy Marie-Lou Gaucher Louise Lessard Danielle Leblanc Alain Houde 《Canadian journal of veterinary research》2005,69(3):200-207
The purpose of the study, carried out in a beef processing plant, was to evaluate the effectiveness of a new prototype for steam pasteurization treatment in controlling microbiological hazards. Samples were taken by swabbing randomly selected sites before and after pasteurization and again after chilling to obtain total aerobic counts (TAC), total coliform counts (TCC), and generic Escherichia coli counts (ECC) on Petrifilm plates and to determine the prevalence of Salmonella spp., Listeria monocytogenes, and E. coli O157:H7 using standard enrichment techniques. Escherichia coli and L. monocytogenes strains were tested for various factors associated with their virulence by using colony hybridization and polymerase chain reaction (PCR), respectively. Antimicrobial susceptibility was determined for each isolate that was potentially pathogenic to humans by using the disk-diffusion method. Mean values for TAC, TCC, and ECC were 2.18, 0.16, and 0.06 log10 CFU/cm2, respectively, before pasteurization; 1.17, 0.03, and 0.01 log10 CFU/cm2 after pasteurization; and 0.89, 0.02, and 0.01 log10 CFU/cm2 after chilling. Prevalence of L. monocytogenes, Salmonella spp., and E. coli O157:H7 on carcasses was 0.8%, 0.0%, and 0.0%, respectively, before pasteurization; 2.6%, 0.0%, and 0.0% after pasteurization; and 3.1%, 0.1%, and 0.0% after chilling. The prevalence of E. coli containing > or = 1 virulence gene was 14.7%. More specifically, 11.88% of the isolates obtained before pasteurization, 22.2% obtained after pasteurization, and 31.2% obtained after chilling had virulence genes. All L. monocytogenes isolates tested positive for the presence of 3 major virulence factors (hlyA, inlB, and plcB). Antibiograms showed that certain isolates were susceptible to all antibiotics, some showed an intermediate sensitivity, and others were multiresistant. Overall, these results suggest that steam pasteurization is an effective means of improving safety quality of beef carcasses. However, pasteurization may indirectly contribute to the growth of some pathogenic microorganisms, such as L. monocytogenes. 相似文献
63.
Mortality of pear psylla to amitraz was studied by means of bioassays. Variation between samples, temporal variation within the season in one orchard and spatial variation between Swiss regions were considered. Variation between samples was large enough to produce different Probit functions and LC50 values. Temporal and spatial variations were too small to indicate resistance. Prediction intervals of the pooled functions using bootstrapping were calculated to determine if future samples come from a population with decreased sensitivity. Probabilistic criteria on the population level were proposed for resistance. 相似文献
64.
Zayed Joseph Pitre Janike Rivard Michèle Loranger Sylvain 《Water, air, and soil pollution》1999,109(1-4):137-145
Since 1976, methylcyclopentadienyl manganese tricarbonyl (MMT), an organic derivative of Mn, has been used in Canada as an anti-knock agent in unleaded gasoline. In a preliminary evaluation of the contribution of MMT to urban air pollution, the CO and NOx emissions of 10 vehicles each having traveled less than 17 000 miles were sampled. Five of these vehicles were filled with MMT-free gasoline and the remaining five with MMT-added gasoline. The emissions were evaluated according to the Federal Test Procedure which simulates urban and highway driving cycles. As for the NOx and CO analysis, it was carried out by means of infrared spectrometry, while the concentration of Mn in the gasoline was determined through neutron activation. Overall, the amount of CO emitted by the vehicles using MMT-added gasoline was 1.48 g mile-1 ± 1.77. The amount emitted by the vehicles using clear (MMT-free) gasoline was 0.74 g mile-1 ± 0.88. As for the NOx emission level, it was 0.20 g mile-1 ± 0.15 for the vehicles using MMT-added gasoline vs 0.17 g mile-1 ± 0.18 for the vehicles using clear gasoline. However, probably due to the small sample size and the very high level of emission of one of the vehicles using MMT-added gasoline, these differences are not statistically significant. Further studies should take into account variables such as the driving history and the representativity of the fleet of vehicles tested. 相似文献
65.
Noémie M. Summa David Eshar Bridget Lee-Chow Sylvain Larrat Dorothy C. Brown 《The Canadian veterinary journal. La revue veterinaire canadienne》2014,55(9):865-869
This study compared blood glucose concentrations measured with a portable blood glucometer and a validated laboratory analyzer in venous blood samples of 20 pet ferrets (Mustela putorius furo). Correlation and agreement were evaluated with a Bland-Altman plot method and Lin’s concordance correlation coefficient. Blood glucose concentrations measured with the laboratory analyzer and the glucometer ranged from 1.9 to 8.6 mmol/L and from 0.9 to 9.2 mmol/L, respectively. The glucometer had a poor agreement and correlation with the laboratory analyzer (bias, −0.13 mmol/L; level of agreement, −2.0 to 3.6 mmol/L, concordance correlation coefficient 0.665). The relative sensitivity and specificity of the portable blood glucometer for detection of hypoglycemia were 100% (95% CI: 66% to 100%) and 50% (95% CI: 20% to 80%), respectively. Positive and negative predictive values were 67% (95% CI: 39% to 87%) and 100% (95% CI: 46% to 100%), respectively. Based on these results, clinicians are advised to be cautious when considering the results from this handheld glucometer in pet ferrets, and blood glucose concentrations should be determined with a laboratory analyzer validated for this species. 相似文献
66.
67.
Barrangou R Fremaux C Deveau H Richards M Boyaval P Moineau S Romero DA Horvath P 《Science (New York, N.Y.)》2007,315(5819):1709-1712
Clustered regularly interspaced short palindromic repeats (CRISPR) are a distinctive feature of the genomes of most Bacteria and Archaea and are thought to be involved in resistance to bacteriophages. We found that, after viral challenge, bacteria integrated new spacers derived from phage genomic sequences. Removal or addition of particular spacers modified the phage-resistance phenotype of the cell. Thus, CRISPR, together with associated cas genes, provided resistance against phages, and resistance specificity is determined by spacer-phage sequence similarity. 相似文献
68.
We propose quantitative genetic variation as a useful tool complementary to molecular variation in order to detect changes in biodiversity caused by different human-induced activities. We simulated a metapopulation setting under a number of realistic scenarios caused by anthropogenic activities (population isolation, reduced carrying capacity or reproductive rates, shifts in the local optima, and enhanced environmental variation or mutational rates). The effects on diversity of these scenarios were assessed for neutral variation estimated from molecular markers and for an additive quantitative trait that represents a typical morphological characteristic subject to stabilising selection promoting local adaptation to environmental conditions. The results show that monitoring quantitative genetic variation can be more informative than neutral variation to detect some human-induced environmental or genetic impacts on diversity, both at intra and interpopulation levels. We also compared the precision of diversity estimates obtained from molecular markers and quantitative traits. Under low migration rates and typical selection intensities for the quantitative trait, the precision of estimates can be substantially larger for a quantitative trait than for a single molecular marker. Thus, about 10-20 (2-4) independent markers are necessary for the precision of estimates of heterozygosity (population differentiation) from molecular markers to reach that of genetic variances (differentiation) from quantitative traits. 相似文献
69.
Ashraf Tubeileh Virginie Groleau-Renaud Sylvain Plantureux Armand Guckert 《Soil & Tillage Research》2003,71(2):151-161
Soil compaction is known to affect plant growth. However, most of the information regarding the effects of this factor on carbon partitioning has been obtained on young plants while little is known about the evolution of these effects with plant age. The objective of this work was to investigate how soil compaction affects carbon assimilation, photosynthate partitioning and morphology of maize plants during vegetative growth up to tassel initiation. A pressure was applied on moist soil to obtain a bulk density of 1.45 g cm−3 (compacted soil (CS) treatment) while the loose soil (LS) treatment (bulk density of 1.30 g cm−3) was obtained by gentle vibration of soil columns. Plants were grown in a growth chamber for 3–6 weeks and carbon partitioning in the plant–soil system was evaluated using 14C pulse-labelling techniques. Soil compaction greatly hampered root elongation and delayed leaf appearance rate, thereby decreasing plant height, shoot and root dry weights and leaf area. The increase in soil bulk density decreased carbon assimilation rate especially in early growth stages. The main effect of soil compaction on assimilate partitioning occurred on carbon exudation, which increased considerably to the detriment of root carbon. Furthermore, soil microbial biomass greatly increased in CS. Two hypotheses were formulated. The first was that increasing soil resistance to root penetration induced a sink limitation in roots and this increased carbon release into the soil and resulted in a root feedback that regulated carbon assimilation rate. The second hypothesis relies on soil–plant water relations since, due to compaction, the pore size distribution has to be considered. In a compacted soil, the peak of the pore size distribution curve is shifted towards the small pore size. The volume of small pores increases and the unsaturated conductivity decreases substantially, when compared to non-compacted soil. Due to small hydraulic conductivity, the inflow into the roots is well below optimum and the plant closes stomata thus reducing carbon assimilation rate. The effects of soil compaction persisted with plant age although the difference between the two treatments, in terms of percentage, decreased at advanced growth stages, especially in the case of root parameters. 相似文献
70.
Inhibition of apple polyphenol oxidase activity by procyanidins and polyphenol oxidation products 总被引:4,自引:0,他引:4
Le Bourvellec C Le Quéré JM Sanoner P Drilleau JF Guyot S 《Journal of agricultural and food chemistry》2004,52(1):122-130
The rate of consumption of dissolved oxygen by apple polyphenol oxidase in cider apple juices did not correlate with polyphenol oxidase activity in the fruits and decreased faster than could be explained by the decrease of its polyphenolic substrates. The kinetics parameters of a crude polyphenol oxidase extract, prepared from apple (Braeburn cultivar), were determined using caffeoylquinic acid as a substrate. Three apple procyanidin fractions of n 80, 10.5, and 4 were purified from the parenchyma of cider apples of various cultivars. Procyanidins, caffeoylquinic acid, (-)-epicatechin, and a mixture of caffeoylquinic acid and (-)-epicatechin were oxidized by reaction with caffeoylquinic acid o-quinone in order to form oxidation products. All the fractions were evaluated for their inhibitory effect on PPO activity. Native procyanidins inhibited polyphenol oxidase activity, the inhibition intensity increasing with n. The polyphenol oxidase activity decreased by 50% for 0.026 g/L of the fraction of n 80, 0.17 g/L of the fraction of n 10.5, and 1 g/L of the fraction of n 4. The inhibitory effect of oxidized procyanidins was twice that of native procyanidins. Oxidation products of caffeoylquinic acid and (-)-epicatechin also inhibited polyphenol oxidase. 相似文献