| 1. |
|
|
| 2. |
- Duse, Anna
(författare)
-
Antimicrobial resistant Escherichia coli in faeces from preweaned dairy calves : prevalence, risk factors, and spread
- 2015
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Antimicrobial resistant (AMR) bacteria are increasing threats for human and veterinary medicine. Faecal Escherichia coli (E. coli) from preweaned dairy calves is often resistant to multiple antimicrobials and calves may therefore serve as reservoirs for these bacteria and their resistance genes. This thesis investigated the prevalence, risk factors, and spread of resistant E. coli on Swedish dairy farms, with special emphasis on quinolone resistant E. coli (QREC). Faecal samples from preweaned calves and post-partum cows were analysed for resistant E. coli and set in relation to potential risk factors. The farm environment was sampled to study the occurrence and spread of QREC. The occurrence of faecal resistant E. coli in calves was strongly age-dependent, but was also associated with herd size, milking system, calf housing, and geographic location of the farm. Treatment with some broad-spectrum antimicrobials in cows or calves increased the occurrence of resistant E. coli in calves. Feeding waste milk (WM) from cows treated with antimicrobials during lactation to calves increased the proportion of streptomycin and quinolone resistant E. coli in calves, but feeding waste colostrum from cows treated with antimicrobials at drying off had no effect on AMR E. coli. Feeding such colostrum or milk to calves was a common practice on Swedish dairy farms, in particular on farms in southern Sweden, on non-organic farms, and on farms with tie stall housing. On farms where QREC is common in faeces of calves, these bacteria were also widespread in the farm environment. In particular, the calf feed andwater trough contained QREC. The same QREC genotype was found throughout the same and on different farms, suggesting contagious spread of QREC within and between farms. Fluoroquinolone treatment, WM feeding, group calving, poor farm hygiene, purchasing cattle or shared animal transports were some risk factors for increasing the occurrence of QREC on the farm. Altogether, the results indicate that proper biosecurity and improved hygiene, less exposure to broad-spectrum antimicrobials, and restrictive waste milk feeding may be important factors to reduce the burden of AMR E. coli on dairy farms.
|
|
| 3. |
- Duse, Anna, et al.
(författare)
-
Farming practices in Sweden related to feeding milk and colostrum from cows treated with antimicrobials to dairy calves
- 2013
-
Ingår i: Acta Veterinaria Scandinavica. - : Springer Science and Business Media LLC. - 0044-605X .- 1751-0147. ; 55
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Milk produced by cows in receipt of antimicrobial therapy may contain antimicrobial residues. Such antimicrobial-containing waste milk must be withdrawn from human consumption and is therefore sometimes used as calf feed. Unfortunately, this approach might promote selection of antimicrobial resistant bacteria in the calves' intestinal microbiota. The objectives of this study were therefore to obtain an overview of waste milk feeding practices on Swedish dairy farms and to investigate if these practices were associated with certain farm characteristics. A representative group of 457 Swedish dairy farmers participated in a web-based survey with questions about the use of colostrum and milk from cows treated with antimicrobials at dry off or during lactation, respectively, as calf feed. Results: Colostrum (milk from the first milking after calving) and transition milk (milk from the second milking to the fourth day after calving) from cows treated with antimicrobials at dry off was fed to calves on 89% and 85% of the farms in the study, respectively. When antimicrobial therapy was given to cows during lactation, 56% of the farms fed milk that was produced during the course of treatment to calves, whereas milk that was produced during the subsequent withdrawal period was fed to calves on 79% of the farms. Surveyed farmers were less prone to feed such milk if the antimicrobial therapy was due to mastitis than other infections. In Sweden, a majority of antimicrobial treatments during lactation are systemic administration of benzylpenicillin and thus, the bulk of waste milk in Sweden is likely to contain residues of this drug. Feeding waste milk to calves was more common on non-organic farms, and on farms located in Southern Sweden, and was less common on farms with cows housed in cold free stalls barns. Conclusions: Waste milk that may contain antimicrobial residues is, at least occasionally, used as feed for calves on a majority of surveyed Swedish dairy farms. Future work should focus on the effect of waste milk feeding on the occurrence of antimicrobial resistant bacteria in the calves' intestinal microbiota.
|
|
| 4. |
- Duse, Anna, et al.
(författare)
-
Occurrence and Spread of Quinolone-Resistant Escherichia coli on Dairy Farms
- 2016
-
Ingår i: Applied and Environmental Microbiology. - 0099-2240 .- 1098-5336. ; 82, s. 3765-3773
-
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.
|
|
| 5. |
- Duse, Anna, et al.
(författare)
-
Risk factors for antimicrobial resistance in fecal Escherichia coli from preweaned dairy calves
- 2015
-
Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 98, s. 500-516
-
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.
|
|
| 6. |
- Duse, Anna, et al.
(författare)
-
Risk factors for quinolone-resistant Escherichia coli in feces from preweaned dairy calves and postpartum dairy cows
- 2015
-
Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 98, s. 6387-6398
-
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.
|
|
| 7. |
- Hang, Bui Phan Thu, et al.
(författare)
-
High level of multidrug-resistant Escherichia coli in young dairy calves in southern Vietnam
- 2019
-
Ingår i: Tropical Animal Health and Production. - : Springer. - 0049-4747 .- 1573-7438. ; 51, s. 1405-1411
-
Tidskriftsartikel (refereegranskat)abstract
- This study investigated the occurrence of antimicrobial-resistant Escherichia coli in dairy calves in southern Vietnam. Fecal samples were taken directly from the rectum of 84 calves from 41 smallholder dairy farms, when newborn and at 14 days of age for isolation of E. coli. Escherichia coli strains were isolated from 144 of the 168 fecal samples tested. Of the 144 E. coli isolates, 40% were found to be susceptible to all 12 antimicrobial drugs tested and 53% of the E. coli isolates were resistant to at least three antimicrobials. Calves were colonized with antimicrobial-resistant E. coli already on the day of birth. Resistance to tetracycline was most common, followed by resistance to sulfamethoxazole, ampicillin, trimethoprim, and ciprofloxacin. Four isolates carried a gene encoding for extended-spectrum cephalosporinases (ESC), and these genes belonged to blaCTX-M group 1 (2 isolates), blaCTX-M group 9 (1 isolate), and blaCMY-2 (1 isolate). Thirty-three isolates had a plasmid-mediated quinolone resistance (PMQR) phenotype, and 30 of these carried the qnrS gene. These results are of importance for management routines of dairy cattle to prevent the spread of antimicrobial resistance.
|
|
| 8. |
- Persson Waller, Karin, et al.
(författare)
-
Veterinary treatment strategies for clinical mastitis in dairy cows in Sweden
- 2016
-
Ingår i: Veterinary Record. - : Wiley. - 0042-4900 .- 2042-7670. ; 178
-
Tidskriftsartikel (refereegranskat)abstract
- To evaluate if Swedish veterinary guidelines on use of antimicrobials in cases of clinical mastitis in dairy cows have been adopted by veterinary practitioners, their treatment strategies were evaluated in a cross-sectional study using a web-based questionnaire. Another aim was to study if the strategies differed among veterinarians due to year and country of exam, sex, region, numbers of mastitis cases per month, and postgraduate training in herd health using multivariable logistic regression models. In total, 267 of 741 (36 per cent) veterinarians contacted answered the questionnaire satisfactorily. Most considered bacteriological diagnostics important, but many veterinarians made treatment decisions without collecting information on antimicrobial susceptibility. Moreover, few veterinarians used measuring tape to assess bodyweight before dosing parenteral antimicrobials. Year of exam and postgraduate training were the veterinary demographic factors associated with most treatment routines. The questions associated with most demographic factors were if antimicrobial treatment is affected by knowledge on earlier udder pathogens in the herd, and how often NSAID and follow-up of treatment using milk somatic cell count are used. Overall, the veterinarians followed the Swedish guidelines rather well, but discrepancies in need for improvement were found.
|
|
