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1.
Mikaelian I Ouellet M Pauli B Rodrigue J Harshbarger JC Green DM 《Diseases of aquatic organisms》2000,40(3):195-201
Myositis associated with infection by Ichthyophonus-like organisms was diagnosed in 35 of 260 (13%) wild amphibians collected in Quebec, Canada, from 1959 to 1964 (n = 30), and 1992 to 1999 (n = 230). Infection was diagnosed in 17 green frogs Rana clamitans, 9 wood frogs R. sylvatica, 4 red-spotted newts Notophthalmus viridescens, 3 bullfrogs R. catesbeiana, 1 spring peeper Pseudacris crucifer, and 1 pickerel frog R. palustris. The spring peeper and one of the bullfrogs were collected in 1964 from the Mont Saint-Hilaire Biosphere Reserve, indicating long-term presence of the organism. Spores of the organisms invaded striated muscle fibers and were associated with variable degrees of granulomatous and eosinophilic inflammation. Infection was considered fatal in 2 green frogs, 1 wood frog, and 1 red-spotted newt. It was considered potentially significant in 3 additional green frogs in which up to 100% of the fibers of some muscles were replaced by spores associated with a severe granulomatous reaction. Ultrastructural features of Ichthyophonus-like spores included a thick trilaminated wall, a paramural cytoplasm, multiple nuclei, oval mitochondria with short tubulo-vesicular cristae and numerous ribosomes. This report represents 4 new host records and shows that ichthyophonosis is enzootic in amphibians from Quebec. 相似文献
2.
Erin E. Rees Denise Bélanger Frédérick Lelièvre Nathalie Coté Louise Lambert 《The Journal of wildlife management》2011,75(6):1406-1416
Data from wildlife disease surveillance programs are used to inform implementation of disease control (e.g., vaccination, population reduction) in space and time. We developed an approach to increase detection of raccoon rabies in raccoons (Procyon lotor) and skunks (Mephitis mephitis) of Québec, Canada, and we examined the implications of using this approach for targeted surveillance. First we modeled the probability of a rabid animal relative to environmental characteristics of sampling locations. Rabid animals were more likely to be found in low-lying flat landscapes that had higher proportions of corn-forest edge habitat and hay agriculture, and that were within 20 km of one or more known rabies cases. From the model, we created 2 complementary risk maps to identify areas where rabid animals were most likely to be sampled. One map accounted for habitat and known rabies case locations, and can be used to define an infection zone from which surveillance can be targeted along the periphery to determine if disease is continuing to spread. The other map only accounted for habitat and can be used to locate areas most likely to contain rabid animals when the disease is present. In a further analysis we compared the 2 most successful methods for detecting raccoon rabies in Québec, given the disease was present. Government trapping operations (active surveillance) detected more cases in the short-term, but citizen notification (passive and enhanced) was more effective after 12 trapping days from which the initial rabies case was found. Our approach can benefit wildlife and public health agencies wanting to assess the disease status of regions by targeting surveillance to habitats most likely to contain infected animals and by defining the duration over which sampling methods are effective. © 2011 The Wildlife Society. 相似文献
3.
C. Ansseau 《Plant Ecology》1993,106(2):127-136
Patterns in vegetation landscapes depend on a complex interplay between processes operating at various scales in time and space. Large-scale variations in environmental factors such as climate and landforms set a background in which smaller local-scale processes are involved. Disturbances superimpose variations on environmental factors and are also dependent on these. Stream valleys of hilly land in Southern Québec have been examined at different scales. Vegetation landscape units have been characterized at the level of landform (vegetation pattern), topographic gradient (geosigmassociation) and ecosite (synassociation). Extension of the methodology up to biogeographical units and practical applications are considered. xx]Nomenclature: plants: Scoggan, 1979; phytosociological units: Ansseau \s& Grandtner, 1986 \s& 1988; Theurillat \s& Moravec, 1990a, b. papers presented at the Vth INTECOL Congress at Yokohama 1990. 相似文献
4.
Swadling Kerrie M. Gibson John A.E. Pienitz Reinhard Vincent Warwick F. 《Hydrobiologia》2001,(1):341-350
We aimed to determine whether the copepod assemblages in lakes and ponds of northern Québec, Canada, were closer in composition to those found in southern Québec, or to those reported from the subarctic and arctic. Six calanoid and five cyclopoid species were identified from 37 ponds and lakes located in the region between 55° N and 59° N. Species diversity was generally low, ranging from 0 to 4 species per lake. Dominant species were Leptodiaptomus minutus and Acanthocyclops vernalis. The species assemblages showed high affinity with those found in forested regions of southern Québec. Exceptions were Leptodiaptomus tyrrelli, previously only recorded west of Hudson Bay, and Hesperodiaptomus arcticus, hitherto recorded north of 58° N. Relationships between the lakes, species, and environmental variables were explored using multivariate analysis. Lakes situated along the coast and on two offshore islands clustered together and were characterised by higher conductivity and pH than those lakes located further inland. Leptodiaptomus tyrrelli was common in these coastal lakes. Canonical correspondence analysis revealed statistically significant relationships between copepod distributions and conductivity, dissolved organic carbon and pH. These three variables accounted for 70% of the variation in the species' distribution. 相似文献
5.
C Dionne C Gagné P Julien M R Murthy M Lambert G Roederer J Davignon M R Hayden P J Lupien M de Braekeleer 《Annales de génétique》1992,35(2):89-92
Familial hyperchylomicronemia due to the lipoprotein lipase (LPL) activity deficiency (Type I hyperlipoproteinemia) is an autosomal recessive disorder with a prevalence estimated at one case per million. Thirty-four type I individuals are known in Saguenay-Lac-St-Jean (SLSJ), a geographically isolated region of Quebec. The prevalence of type I and LPL deficient heterozygote in this region was estimated at 1/6382 and 1/46 inhabitants respectively. The mean inbreeding coefficient was slightly elevated in the type I group compared with three control groups. The mean kinship coefficient was 15.1 times higher in the type I group than in the control groups. The high prevalence of type I in SLSJ appears to be the result of the emigration of carriers of LPL deficiency from Charlevoix, another isolated region of quebec to the SLSJ region. Endogamy also played a crucial role in increasing the prevalence of type I in SLSJ. 相似文献
6.
Hervé Van der Heyden Pierre Dutilleul Marc-Olivier Duceppe Guillaume J. Bilodeau Jean-Benoît Charron Odile Carisse 《Molecular Plant Pathology》2022,23(3):339-354
Several Peronospora species are carried by wind over short and long distances, from warmer climates where they survive on living plants to cooler climates. In eastern Canada, this annual flow of sporangia was thought to be the main source of Peronospora destructor responsible for onion downy mildew. However, the results of a recent study showed that the increasing frequency of onion downy mildew epidemics in eastern Canada is associated with warmer autumns, milder winters, and previous year disease severity, suggesting overwintering of the inoculum in an area where the pathogen is not known to be endogenous. In this study, genotyping by sequencing was used to investigate the population structure of P. destructor at the landscape scale. The study focused on a particular region of southwestern Québec—Les Jardins de Napierville—to determine if the populations were clonal and regionally differentiated. The data were characterized by a high level of linkage disequilibrium, characteristic of clonal organisms. Consequently, the null hypothesis of random mating was rejected when tested on predefined or nonpredefined populations, indicating that linkage disequilibrium was not a function of population structure and suggesting a mixed reproduction mode. Discriminant analysis of principal components performed with predefined population assignment allowed grouping P. destructor isolates by geographical regions, while analysis of molecular variance confirmed that this genetic differentiation was significant at the regional level. Without using a priori population assignment, isolates were clustered into four genetic clusters. These results represent a baseline estimate of the genetic diversity and population structure of P. destructor. 相似文献
7.
Lydia Querrec Louise Filion Réginald Auger Dominique Arseneault 《Dendrochronologia》2009,27(3):199-212
In Québec City, a segment of an old wooden palisade built for protection was found buried in situ. The palisade was excavated by the Laval University archaeology field school in 2004–2005, and 29 posts were recovered and sampled. The palisade enclosed the Intendant's Palace compound, which was the residence of the governor of New France at the end of the 17th century. Tree-ring analysis was performed on wood excavated from the Intendant's Palace archaeological site (PDI) and additional wood from two historical military buildings, the Artillery Park (ART) (early 18th century) and the Québec Citadel (CIT) (17th–19th centuries). Wood identification revealed that white cedar (Thuja occidentalis L.) was used for wood construction at the three sites. Many trees used for the construction of the PDI palisade were felled after the 1690 growing season, likely in September/October 1690. Posts probably came from trees growing close to the site on the banks of the Saint-Charles River. A white cedar ring-width chronology from the Rimouski area, approximately 300 km northeast of Québec City, along the St. Lawrence River, was used for cross-dating. Archaeological and historical wood samples from two of the three sites (PDI and ART) were first assembled in a 235-year tree-ring chronology, called the Québec chronology, extending from 1489 to 1723. The two master chronologies (Québec and Rimouski) were merged into a single 513-year tree-ring chronology (1489–2001), called the Saint-Laurent chronology. 相似文献
8.
9.
Diane Saint-Laurent Francis Baril Marlies Hähni Maxime C. Paré 《Soil & Sediment Contamination》2014,23(1):76-93
Hydrocarbon-contaminated layers found over 100 kilometers of riverbanks (southern Québec) were investigated. Analytical results for hydrocarbons, trace metals, Pb concentrations, and Pb isotopic signatures (206Pb/207Pb, 208Pb/206Pb, 204Pb/206Pb) of contaminated soil are presented. Soil samples show hydrocarbon concentrations (C10-C50) ranging from <60 to 660 mg kg?1. Higher concentrations were found in the Richmond site (southern Québec). The values for Pb-concentrations ranged between 7 and 149 mg kg?1 with median value of 23 mg kg?1. For the Pb isotope ratios, the values obtained in the hydrocarbon layer range from 1.124 to 1.175 ± 0.011 (206Pb/207Pb), 2.085 to 2.126 ± 0.011 (208Pb/206Pb), and 0.054 to 0.057 ± 0.000 (204Pb/206Pb). The combination of various techniques used allows us to distinguish the various sources of contaminants. The study also reveals that Pb and other trace metal elements continue to be found in the fluvial environment, even after many years, and this soil pollution could affect the quality of streams and living organisms. 相似文献
10.
Longitudinal variations of phytoplankton biomass and composition were assessed in a 250 km-long section of the St.Lawrence River, which alternately runs through narrow (< 2 km) river cross sections and wide (up to 10 km) fluvial lakes. In the main river stem, concentrations of suspended matter and total phosphorus increased with distance downstream, whereas light penetration decreased. Seasonal changes in plankton composition and biomass were more important than those resulting from differences in water mass (tributary) of origin. Sampling at three cross river sections and in two fluvial lakes showed a progressive downstream decrease in phytoplankton biomass and changes in size structure and taxonomic composition. River plankton was primarily composed of small (< 10 µm equivalent spherical diameter), truly planktonic cells belonging to Cryptophyceae and diatoms, with Chlorophyceae in summer. Plankton sampled in summer among rooted macrophytes in fluvial lakes exhibited a higher biomass of resuspended periphytic algae than in the main river stem, which contributed slightly to downstream phytoplankton biomass.Successive river cross sections always shared about 50% of their taxa, indicating a rapid downstream transport of algae within the main water mass. However, the proportion of species common to all cross sections was highest during the spring freshet, and lowest during summer low discharge, likely resulting from the development of a distinct flora in fluvial lakes during summer. Conversely, about 30% of the identified taxa were exclusive to a cross section and were replaced by others occurring downstream. Overall, phytoplankton composition along the St.Lawrence River is primarily controlled by advective forces, which result in a homogeneous flora in the main river stem, with a local contribution of resuspended periphyton from fluvial lakes. 相似文献
11.
《Aquatic Botany》1987,29(3):195-204
Aboveground production of macrophytes in tidal marshes was studied for 3 years at Montmagny and Cap St. Ignace on the south shore of the St. Lawrence River in Québec, Canada. Year-to-year variation of production of the dominant species, Scirpus americanus Pers., was observed and related to variation in weather during the growing season. With the exception of Zizania aquatica L., relative production of the macrophytes for different parts of the marshes remained constant in successive years. A multiple regression procedure was used to establish the relationship between production and a series of independent variables including biotic (goose use and plant competition) and abiotic factors (submersion, substrate hardness, soil texture and sedimentation). A lower percentage of organic matter in the soil and a firm substrate were associated with a greater production of S. americanus. Accretion of sediments was positively correlated with the production of S. americanus and Sagittaria spp., whereas the percentage of time of submersion was negatively related with production of Sagittaria spp., Eleocharis spp. and Scirpus torreyi Olney. Competitive interference was apparent between S. americanus and S. torreyi and between Eleocharis spp. and Zizania spp. No measured abiotic characteristic of the marsh explained the variation of Zizania production. 相似文献
12.
François Courchesne Marie-Claude Turmel Benoît Cloutier-Hurteau Simon Constantineau Lara Munro Michel Labrecque 《International journal of phytoremediation》2017,19(6):545-554
The phytoextraction of the trace elements (TEs) As, Cd, Cu, Ni, Pb, and Zn by willow cultivars (Fish Creek, SV1 and SX67) was measured during a 3-year field trial in a mildly contaminated soil. Biomass ranged from 2.8 to 4.4 Mg/ha/year at 30,000 plants/ha. Shoots (62%) were the main component followed by leaves (23%) and roots (15%). Biomass was positively linked to soluble soil dissolved organic carbon, K, and Mg, while TEs, not Cd and Zn, had a negative effect. The TE concentration ranking was: Zn > Cu > Cd > Ni, Pb > As, and distribution patterns were: (i) minima in shoots (As, Ni), (ii) maxima in leaves (Cd, Zn), or (iii) maxima in roots (Cu, Pb). Correlations between soil and plant TE were significant for the six TEs in roots. The amounts extracted were at a maximum for Zn, whereas Fish Creek and SV1 extracted more TE than SX67. More than 60% (91–94% for Cd and Zn) of the total TE was in the aboveground parts. Uptake increased with time because of higher biomass. Fertilization, the selection of cultivars, and the use of complementary plants are required to improve productivity and Cd and Zn uptake. 相似文献
13.
Plants are chronically associated with microorganisms, residing all tissues. Holonomic analysis of diversity of established rhizobacteria in uncultivated plants is scarce. Thus, the present study was conducted to access the root-associated bacterial diversity of 6 crops (maize, canola, soybean, reed canarygrass, alfafa, and miscanthus) and 20 uncultivated plant species in the region of Sainte-Anne-de-Bellevue, Québec, Canada, using pure-culture methods. Based on 16S rRNA gene sequence analysis, 446 bacterial isolates were distributed onto four phyla (Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes), 32 families and 90 genera. Proteobacteria constituted the largest group of isolates (240), 40% of ectophytic and 61% of endophytic bacteria. Representatives of the genera Bacillus and Pseudomonas dominated in rhizosphere soil; Microbacterium and Pseudomonas were the predominant endophytes. Some genera were associated with specific plant species, such as Stenotrophomonas, Yersinia, Labrys and Luteibacter. Several endophytes were occasionally observed in the rhizosphere, and vice versa. This is the first survey of culturable endophytic bacteria associated with uncultivated plants in Québec. The culturable bacterial community studied herein are assumed to represent a portion of the entire phytomicrobiome of the evaluated plants. Results confirmed that the crops and uncultivated plants of Québec represent an extremely rich reservoir of diverse rhizobacteria. 相似文献
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15.
The weevil Listronotus maculicollis Dietz (Coleoptera: Curculionidae) is a major pest of annual bluegrass, Poa annua L., on golf courses in northeastern North America. To determine the distribution, abundance, and seasonal ecology of L. maculicollis on golf courses in Québec, Canada, we sampled 19 golf courses (GC1-GC19) from different geographic and climatic conditions during 2001, 2002, and 2003. L. maculicollis was found on all golf courses except GC19, which was located in northeastern Québec. In most sites, L. maculicollis completed two generations per year. A linear regression model comparing L. maculicollis larval densities as a function of spatial coordinates revealed that L. maculicollis were more abundant in western Québec than in eastern Québec. Pearson correlations on the probability of both L. maculicollis larval and pupal presence with soil parameters indicated significant positive correlations for fine sand (larvae) and soil pH (pupae) and negative correlations for gravel. 相似文献
16.
Viruses were found to be very abundant in the top layer of the sediments of Lac Gilbert, Québec. Viruses were extracted from the sediments using pyrophosphate buffer, and viruses from the diluted extracts were pelleted onto grids and enumerated using transmission electron microscopy. Viral abundance in the sediments ranged from 6.5 × 108 to 1.83 × 1010 ml–1, which is 10- to 1,000-fold greater than the number observed in the water column. This increase corresponds well with the 100- to 1,000-fold increase in bacterial abundance in the sediments. Viral abundance differed significantly among the surface sediment samples taken at different bottom depths and among samples taken at different depths of the water column. Viral abundance also varied significantly between the oxic and anoxic zones of the water column and the sediments. The virus-to-bacteria ratio varied greatly among the different sediment sites but not among depths in the water column. Viral abundance in the water column was related to bacterial abundance and chlorophyll concentration, whereas viruses in the sediments were most abundant in sediments with high organic matter content. Elevated viral abundance and their erratic distribution in the sediments suggest that viruses might play an important role in sediment microbial dynamics.
Correspondence to: Roxane Maranger 相似文献
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18.
Gosia K. Kozak David L. Pearl Julia Parkman Richard J. Reid-Smith Anne Deckert Patrick Boerlin 《Applied and environmental microbiology》2009,75(18):5999-6001
Sulfonamide-resistant Escherichia coli and Salmonella isolates from pigs and chickens in Ontario and Québec were screened for sul1, sul2, and sul3 by PCR. Each sul gene was distributed differently across populations, with a significant difference between distribution in commensal E. coli and Salmonella isolates and sul3 restricted mainly to porcine E. coli isolates.Resistance to sulfonamides is frequent in bacteria from farm animals (7, 8, 9, 10) and is usually caused by the acquisition of the genes sul1, sul2, and sul3 (20, 22). The objectives of this study were (i) to assess the distribution of these genes in Escherichia coli and Salmonella enterica isolates in swine and chickens from two major provinces in Canada, (ii) to assess whether differences occur in the distribution of these genes among bacterial species found within two different animal host species, and (iii) to assess whether significant differences in the distribution of these genes are present between the commensal E. coli strains used as indicators for surveillance of antimicrobial resistance and the zoonotic Salmonella pathogens found in the same ecological niche. In contrast to previous studies, a multivariable logistic regression model was used to analyze the data, control for confounding factors, and assess the interaction effect between animal and bacterial species in terms of the probability of an isolate carrying a specific sul gene. The distribution of sulfonamide resistance genes among sulfonamide-resistant E. coli (393 isolates from chickens and 311 from swine) and Salmonella (13 isolates from chickens and 221 from swine) isolates was assessed. These isolates were collected by the Canadian Integrated Program for Antimicrobial Resistance Surveillance (CIPARS) between 2003 and 2005 from ceca of apparently healthy animals at abattoirs in Ontario (n = 435) and Québec (n = 503). The methods used by CIPARS are presented in detail elsewhere (8-10). The isolates were screened with a previously published multiplex PCR for sul1, sul2, and sul3 (16). The sul1 and sul2 genes were found in E. coli and Salmonella isolates from both animal species. The sul3 gene was detected in both E. coli and Salmonella isolates from swine but only in E. coli isolates from chickens (Table (Table1).1). Three percent of the isolates had no detectable sul gene, 12.5% possessed two genes, and two isolates carried three genes (Table (Table1).1). Similar (2, 3, 14, 19) or higher (4, 11, 17) values for multiple genes have been reported by others. The overall higher prevalence of sul1 in Salmonella isolates and of sul2 and sul3 in E. coli isolates was in agreement with the results of previous studies (2-4, 11, 12, 14, 21).
Open in a separate windowThree logistic regression models (Table (Table2)2) for associations between the presence of each sul gene and the bacterial species, animal species, province of origin of the animals, and year of isolation were built using Stata 9 (StataCorp, College Station, TX). Statistical interactions between bacterial and animal species were assessed in the sul1 and sul2 models but not in the sul3 model (the sample size was insufficient). Tests were two tailed, with significance at a P value of ≤0.05. A significant interaction between bacterial and animal species was observed for sul1 (Table (Table2).2). The presence of statistical interactions indicates that the effect of each variable depends on the state of the other variable. Thus, the effects of bacterial and animal species on the distribution of sul1 cannot be interpreted independently. For instance, sul1 was more frequent in Salmonella isolates from swine than from chickens, but the reverse was true for E. coli isolates (Table (Table3).3). Genomic islands containing sul1 are present in some Salmonella serovars, including S. enterica serovar Typhimurium and S. Derby (1, 6, 18), which were the most frequent in the swine samples of this study (Table (Table4).4). This contrasts with E. coli strains, in which sul1 is usually associated with transposons and large transferable plasmids (22). Thus, the presence of significant statistical interactions in the sul1 model could be an indicator of the differential importance of horizontal gene transfer in E. coli strains versus clonal expansion of specific Salmonella serovars in the animal species investigated. No significant interaction was detected for sul2 (P = 0.66) (Table (Table2).2). This could be the consequence of the relatively small number of sul2-positive Salmonella isolates and the resultant lack of statistical power; however, it is also possible that sul2 has a different epidemiology than sul1. The sul2 gene has not been shown to be located on genomic islands and is usually plasmid borne (22). It may therefore be transferred more frequently than sul1 between E. coli and Salmonella and between bacteria from swine and chickens, leading to the absence of a significant interaction in the sul2 model. Serotyping, molecular typing, and assessment of gene transferability would be required to test these hypotheses.
Open in a separate windowaStatistical interaction between data for bacterial species and animal species. The terms for this interaction are described in Table Table33.bExample of odds ratio interpretation: the odds of a porcine isolate carrying sul3 were 39.57 times higher than for an isolate obtained from chickens. NI, not included in the model. The sul2 model was not included because the P value for this interaction was equal to 0.66, and the sul3 model was not included because it did not converge when including this interaction.cP < 0.001.
Open in a separate windowaExample of interpretation: the interaction effect suggests that sul1-mediated sulfonamide resistance is 19.79 times more likely to occur in Salmonella in pigs than in E. coli in pigs.
Open in a separate windowaThe first and second numbers in each column represent swine and chicken isolates, respectively; the total number of tabulated occurrences of sulfonamide genes is larger than the number of resistant isolates investigated because some isolates carried several genes simultaneously.A significant increase in the prevalence of sul3 was detected between 2003 and 2004 (P = 0.007) but not between 2004 and 2005 (P = 0.055) nor at any time for sul1 and sul2 (Table (Table2).2). The sul3 gene has emerged recently (5), and its prevalence was probably still increasing in 2003. The odds of finding sul3 in Salmonella isolates were 10 times lower than for E. coli isolates and 40 times higher in swine than in chickens (Table (Table2).2). Other studies have also found high frequencies of sul3 in porcine E. coli isolates (5, 12, 20) and much lower frequencies in other sources (4, 11, 12, 14). Although these isolates were not typed, previous results have shown that sul3 is present in both pathogenic and commensal porcine E. coli isolates (5) of at least 13 different serotypes (P. Boerlin and R. M. Travis, unpublished data). The sul3 gene has spread extensively across porcine E. coli populations in North America and Europe but remains uncommon in other major farm animal species and in Salmonella populations (Table (Table1)1) (2, 13). It may require more time to spread to other populations. There may be biological and ecological barriers slowing its spread to bacteria of other animal species or coselection factors that favor its presence in porcine E. coli populations.Using the example of sulfonamides as a model for the application of multivariable statistical approaches to the study of antimicrobial resistance epidemiology, this study indicates that the relative frequencies of genes encoding resistance to the same antimicrobial either present in bacterial populations for decades or recently emerged can vary significantly between animal hosts and phylogenetically related bacterial species sharing the same ecological niche. Differences in the distribution of resistance determinants may remain hidden when assessing resistance phenotypes. Similar antimicrobial susceptibility results do not necessarily imply similar resistance genes. These findings highlight the need to further explore the interactions between commensals and pathogens and the ways in which commensal bacteria are interpreted as indicators of antimicrobial resistance in pathogens. 相似文献
TABLE 1.
Frequency of the three resistance genes sul1, sul2, and sul3 in sulfonamide-resistant E. coli and Salmonella isolates from chickens and swine in Ontario and Québec between 2003 and 2005Bacterial species | Source (no. of isolates) | No. (%) of isolates with indicated gene(s)
| |||||||
---|---|---|---|---|---|---|---|---|---|
sul1 | sul2 | sul3 | sul1 + sul2 | sul1+ sul3 | sul2 + sul3 | sul1 + sul2 + sul3 | None | ||
E. coli | Swine (311) | 61 (19.6) | 66 (21.2) | 132 (42.4) | 11 (3.5) | 9 (2.9) | 11 (3.5) | 2 (0.6) | 19 (6.1) |
Chickens (393) | 103 (26.2) | 211 (53.7) | 9 (2.3) | 64 (16.3) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 6 (1.5) | |
Total (704) | 164 (23.3) | 277 (39.3) | 141 (20.0) | 75 (10.7) | 9 (1.3) | 11 (1.6) | 2 (0.3) | 25 (3.6) | |
Salmonella | Swine (221) | 173 (78.3) | 20 (9.0) | 5 (2.3) | 7 (3.2) | 0 (0.0) | 14 (6.3) | 0 (0.0) | 2 (0.9) |
Chickens (13) | 7 (53.8) | 5 (38.5) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 1 (7.7) | |
Total (234) | 180 (76.9) | 25 (10.7) | 5 (2.1) | 7 (3.0) | 0 (0.0) | 14 (6.0) | 0 (0.0) | 3 (1.3) |
TABLE 2.
Multivariable models for the distribution of the sul1, sul2, and sul3 sulfonamide resistance genes from swine and chickens at slaughter in Ontario and Québec between 2003 and 2005Explanatory variable (referent group) or interaction | Odds ratio (95% confidence interval)b
| ||
---|---|---|---|
sul1 | sul2 | sul3 | |
Salmonella (E. coli) | 1.54 (0.50-4.74) | 0.33 (0.21-0.51) | 0.10 (0.06-0.16) |
Swine (chickens) | 0.49 (0.36-0.68)c | 0.16 (0.12-0.23)c | 39.57 (20.21-77.48)c |
Québec (Ontario) | 0.80 (0.60-1.07) | 2.20 (1.61-2.99)c | 0.83 (0.56-1.23) |
2004 (2003) | 0.77 (0.56-1.06) | 0.99 (0.71-1.40) | 1.84 (1.18-2.86) |
2005 (2003) | 0.68 (0.45-1.04) | 1.36 (0.88-2.09) | 1.66 (0.99-2.79) |
2005 (2004) | 0.88 (0.58-1.36) | 1.36 (0.88-2.11) | 0.90 (0.53-1.53) |
Bacterial species × animal speciesa | 12.84 (3.79-43.46)c | NI | NI |
TABLE 3.
Interaction terms for the association between bacterial and animal species for the presence of sul1Contrast variables | Odds ratioa | 95% Confidence interval | P value |
---|---|---|---|
Salmonella in pigs vs Salmonella in chickens | 6.30 | 1.95-20.39 | 0.002 |
E. coli in pigs vs E. coli in chickens | 0.49 | 0.36-0.67 | <0.001 |
Salmonella in chickens vs E. coli in chickens | 1.54 | 0.50-4.74 | 0.451 |
Salmonella in pigs vs E. coli in pigs | 19.79 | 12.28-31.87 | <0.001 |
TABLE 4.
Salmonella serovars and frequency of resistance genes detected in each serovarSalmonella serovar | No. of isolatesa | No. of isolates with indicated genea
| ||
---|---|---|---|---|
sul1 | sul2 | sul3 | ||
Agona | 14/0 | 14/0 | 0/0 | 0/0 |
Berta | 3/0 | 0/0 | 3/0 | 0/0 |
Bovismorbificans | 1/0 | 0/0 | 0/0 | 0/0 |
Brandenburg | 3/0 | 1/0 | 1/0 | 0/0 |
Derby | 63/0 | 59/0 | 4/0 | 2/0 |
Give O:15+ | 1/0 | 1/0 | 0/0 | 0/0 |
Heidelberg | 2/4 | 0/3 | 0/0 | 2/0 |
4,12:−:− | 3/0 | 3/0 | 0/0 | 0/0 |
4,12:i:− | 2/0 | 2/0 | 0/0 | 0/0 |
4,5,12:−:− | 1/0 | 1/0 | 0/0 | 1/0 |
Rough-O:fg:− | 1/0 | 1/0 | 0/0 | 0/0 |
Rough-O:l,v:enz15 | 1/0 | 1/0 | 1/0 | 0/0 |
Infantis | 3/0 | 1/0 | 2/0 | 0/0 |
Johannesburg | 1/0 | 1/0 | 0/0 | 0/0 |
London | 2/0 | 1/0 | 0/0 | 1/0 |
Manhattan | 2/0 | 0/0 | 2/0 | 0/0 |
Mbandaka | 6/0 | 6/0 | 1/0 | 0/0 |
Ohio O:14+ | 1/0 | 0/0 | 1/0 | 0/0 |
Putten | 1/0 | 1/0 | 0/0 | 0/0 |
Schwarzengrund | 0/6 | 0/1 | 0/5 | 0/0 |
Typhimurium | 110/3 | 101/3 | 12/0 | 13/0 |
Total | 221/13 | 194/7 | 27/5 | 19/0 |
19.
In a declining sugar maple (SM) stand, we tested the hypothesis that an increasing relative abundance of American beech (AB)
and yellow birch (YB) would improve litter quality by providing a higher proportion of litterfall richer in base cations and
lower in acidity. From 1989 to 2006, SM leaf fall diminished from 59% (1,718 kg ha−1 year−1) to 36% (915 kg ha−1 year−1) of the total leaf fall biomass. Overall, the increase in AB and YB litterfall compensated for the SM decrease, resulting
in constant annual leaf litterfall fluxes (2,803 kg ha−1 year−1) over the period studied. However, because the leaf litter for AB and YB had Ca and Mg concentrations 2–3 times higher than
did SM, Ca and Mg concentrations and fluxes in leaf litterfall significantly increased between 1989 and 2006. Leaf litterfall
of AB and YB also has a higher base/acid ratio than SM. Consequently, changes in forest composition following SM decline led
to a clear improvement in litterfall quality in terms of base cations content and fluxes and acid–base properties. 相似文献
20.
《FEMS microbiology letters》1998,162(2):219-226
An Aroclor 1260 (polychlorinated biphenyl, PCB)-laden soil and one heavily contaminated with polycyclic aromatic hydrocarbons (PAHs) from a secure, engineered landfill site in Québec were analyzed for microbial diversity using a clone library of the 16S rDNA sequences. Phylogenetic analysis revealed that three phyla and their major subdivisions of the domain Bacteria were highly represented in these samples despite the high pollution, particularly by PAHs. None of the 16S rDNA sequences obtained matched known sequences from cultivated bacterial species or from 16S rDNA sequences amplified directly from other environmental samples. 相似文献