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- Duse, Anna, et al.
(författare)
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Occurrence and Spread of Quinolone-Resistant Escherichia coli on Dairy Farms
- 2016
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Ingår i: Applied and Environmental Microbiology. - 0099-2240 .- 1098-5336. ; 82, s. 3765-3773
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Tidskriftsartikel (refereegranskat)abstract
- Quinolone-resistant Escherichia coli (QREC) is common in feces from young calves, but the prevalence and genetic diversity of QREC in groups of cattle of other ages and the farm environment are unknown. The aims of the study were to obtain knowledge about the occurrence of QREC on dairy farms, the genetic diversity of QREC within and between farms, and how these relate to the number of purchased animals and geographic distances between farms. We analyzed the within-sample prevalence of QREC in individual fecal samples from preweaned dairy calves and postpartum cows and in environmental samples from 23 Swedish dairy farms. The genetic diversity of the QREC isolates on 10 of these farms was assessed. In general, QREC was more prevalent in the dairy farm environment and in postpartum cows if QREC was commonly found in calves than if QREC was rare in calves. In particular, we found more QREC organisms in feed and water troughs and in environments that may come into contact with young calves. Thus, the results suggest that QREC circulates between cattle and the farm environment and that calves are important for the maintenance of QREC. Some genotypes of QREC were widespread both within and between farms, indicating that QREC has spread within the farms and likely also between farms, possibly through purchased animals. Farms that had purchased many animals over the years had greater within-farm diversity than farms with more closed animal populations. Finally, animals on more closely located farms were more likely to share the same genotype than animals on farms located far apart.
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| 2. |
- Duse, Anna, et al.
(författare)
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Risk factors for antimicrobial resistance in fecal Escherichia coli from preweaned dairy calves
- 2015
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Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 98, s. 500-516
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Tidskriftsartikel (refereegranskat)abstract
- The primary objective of this study was to investigate calf and farm factors associated with antimicrobial-resistant Escherichia coli in the feces of preweaned dairy calves in Sweden. In particular, we investigated the effects of feeding calves colostrum and milk from cows treated with antimicrobials. The secondary objective was to describe the prevalence of resistant E. coli in feces of preweaned dairy calves in Sweden. Fecal samples from 3 calves, aged 7 to 28 d, from 243 farms were analyzed for the within-sample prevalence of E. coli resistant to nalidixic acid, streptomycin, and cefotaxime using selective agars supplemented with antimicrobials. In addition, resistance to 12 antimicrobials was tested in one randomly selected E. coli isolate per calf. Information was collected from the farmers via questionnaires regarding the use of colostrum and milk from cows treated with antimicrobials as calf feed and other uses of antimicrobials in the herd. Multivariable zero-inflated negative binomial and logistic regression models were used to assess the effect of various risk factors for shedding of resistant E. coli. Escherichia coli resistant to streptomycin, nalidixic acid, or cefotaxime were isolated from 90, 49, and 11% of the calves, respectively. Resistance to at least one antimicrobial was found in a random isolate of E. coli from 48% of the calves. Feeding colostrum from cows treated with antimicrobials at drying off did not affect the prevalence of resistant E. coli. In contrast, feeding milk from cows treated with antimicrobials during lactation resulted in significantly more nalidixic acid- and streptomycin-resistant E. coli than when such milk was discarded; no significant effect was seen for other resistance traits. Furthermore, an interaction was found between feeding milk from cows treated with antimicrobials and use of fluoroquinolones in cows. In general, the prevalence of resistance was lower for older calves and calves on small farms. Other factors that were associated with the shedding of resistant E. coli were administration of oral dihydrostreptomycin to calves, administration of systemic tetracycline and ceftiofur to cows and calves, housing of the calves, predominant breed of the herd, and geographic location of the farm. The presence of resistant E. coli in calves was clearly due to multiple factors, but minimizing the feeding of milk from cows treated with antimicrobials during lactation should lower the prevalence of resistant E. coli in the gastrointestinal tract of the calves.
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| 3. |
- Duse, Anna, et al.
(författare)
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Risk factors for quinolone-resistant Escherichia coli in feces from preweaned dairy calves and postpartum dairy cows
- 2015
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Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 98, s. 6387-6398
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Tidskriftsartikel (refereegranskat)abstract
- Quinolone resistance may emerge in gut bacteria (e.g., in Escherichia coli) of animals. Such bacteria could cause infections in the animal itself or be transmitted to humans via the food chain. Quinolone resistance is also observed in fecal E. coli of healthy dairy cattle, but the prevalence varies between farms, not solely as a result of varying degree of fluoroquinolone exposure. The objective of this study was to identify risk factors for the fecal shedding of quinolone-resistant E. coli (QREC) from dairy calves and postpartum cows. Rectal swabs from 15 preweaned calves and 5 postpartum cows per farm were collected on 23 Swedish dairy farms to determine the prevalence of QREC. Risk factors for the shedding of QREC were investigated using multivariable statistical models. Quinolone-resistant E. coli were found on all but one farm. Factors associated with QREC shedding by calves were being younger than 18 d, being fed milk from cows treated with antimicrobials, recent use of fluoroquinolones in the herd, carriage of QREC by postpartum cows, and using the calving area never or rarely as a sick pen compared with often. Factors associated with QREC shedding by cows were calving in group pens or freestalls compared with single pens or tiestalls, purchasing cattle, sharing animal transports with other farmers, and poor farm hygiene. Proper biosecurity and improved hygiene, as well as minimizing fluoroquinolone exposure and waste milk feeding, may be important factors to reduce the burden of QREC on dairy farms.
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| 4. |
- Fernández-Santoscoy, Maria, et al.
(författare)
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A reduced population of CD103(+)CD11b(+) dendritic cells has a limited impact on oral Salmonella infection
- 2016
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Ingår i: Immunology Letters. - : Elsevier BV. - 0165-2478. ; 176, s. 72-80
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Tidskriftsartikel (refereegranskat)abstract
- CD103(+)CD11b(+) dendritic cells (DC) are the major migratory DC subset in the small intestine lamina propria (siLP) and their survival is dependent on the transcription factor interferon regulatory factor 4 (IRF4). Mice with a DC-specific deletion of irf4 (CD11c-cre.Irf4 mice) have reduced mucosal CD103(+)CD11b(+) DC and altered T cell differentiation to protein antigen. The influence of CD103(+)CD11b(+) DC on oral infection with the gastrointestinal pathogen Salmonella, however, is poorly understood and is investigated here. We show that, despite being infected with Salmonella, CD11c-cre.lrf4 mice (called Cre(+) mice) conserve the reduction in CD103(+)CD11b(+) DC observed in naive Cre(+) mice, particularly in the mesenteric lymph nodes (MLN) but also in the siLP at day 3 post infection. Moreover, Salmonella-infected Cre(+) mice have a similar bacterial burden in intestinal tissues (siLP, MLN and Peyer's patches) as well as the spleen compared to infected Cre-controls. The T cell compartment, including the frequency of IFN-gamma and IL-17-producing T cells, is not altered in intestinal tissues of Salmonella-infected Cre(+) mice relative to infected Cre-controls. In addition, no difference between infected Cre(+) and Cre-mice was observed in either the concentration of IL-6 or IL-17 in whole tissue lysates of siLP, MLN or Peyer's patches or in the serum concentration of Salmonella-specific IgG and IgM. Overall the data suggest that the reduction of CD103(+)CD11b(+) DC in Cre(+) mice has little if any impact on Salmonella burden in infected tissues or eliciting effector functions important in host survival at later stages of the infection. (C) 2016 European Federation of Immunological Societies. Published by Elsevier B.V. All rights reserved.
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| 10. |
- Olofsson, Sara, et al.
(författare)
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Chained Approach vs Contingent Valuation for Estimating the Value of Risk Reduction
- 2016
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- To decide how much resources to spend on reducing mortality risk, governmental agencies in several countries turn to the value of a statistical life (VSL). VSL has been shown to vary depending on the size of the risk reduction, which indicates that WTP does not increase near-proportional in relation to risk reduction as suggested by standard economic theory. Chained approach (CA) is a stated preference method that was designed to deal with this problem. The objective of this study was to compare CA to the more traditional approach contingent valuation (CV). Data was collected from 500 individuals in the Swedish adult general population using two web-based questionnaires, whereof one based on CA and the other on the CV method. Despite the two different ways of deriving the estimates, the methods showed similar results. The CV result showed scale insensitivity with respect to the size of the risk reduction and disease duration and resulted in more zero and protest response. The CA result did also vary depending on the procedure used, but not when chaining on individual estimates. The CA result was also found to be more sensitive to disease duration and severity. This study provides support for the validity of studies of the WTP for a risk reduction. It also shows that CA is associated with encouraging features for the valuation of non-fatal road traffic accidents, but the result does not support the use of one method over the other.
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