Farm-level risk factors for fluoroquinolone resistance in<i>E. coli</i>and thermophilic<i>Campylobacter</i>spp. on finisher pig farms

Taylor, N.M.I.; Clifton-Hadley, F. A.; Wales, Andrew; Ridley, Anne; Davies, RH

doi:10.1017/s0950268808001854

Cited by 29 publications

(62 citation statements)

References 40 publications

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“…Antimicrobial treatment may be necessary in turkey production and this is thought to contribute to the relatively high level of MDR in E. coli from turkeys (Altekruse et al, 2002). Improved biosecurity in itself would contribute to a reduction in the dissemination of resistant organisms (Taylor et al, 2009). …”

Section: Discussionmentioning

confidence: 99%

Ciprofloxacin resistance inE. coliisolated from turkeys in Great Britain

et al. 2012

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Fluoroquinolones are a widely used group of antimicrobials in both human and animal medicine, with ciprofloxacin being a critically important fluoroquinolone for serious human infections. The present study reports on a 1-year survey for the presence of ciprofloxacin-resistant Escherichia coli in turkeys from Great Britain. Boot swabs were taken from 442 turkey flocks comprised of 125 breeding flocks and 317 meat flocks from 337 different farms over a 1-year period (2006 to 2007). CHROMagar ECC containing 1 mg/l ciprofloxacin was used to obtain ciprofloxacin-resistant isolates. Isolates were tested for sensitivity to 16 different antimicrobials. Isolates with ciprofloxacin minimum inhibitory concentrations ]8 mg/l were tested for mutations in gyrA by polymerase chain reaction and DNA sequencing. Selected isolates were tested by multiplex polymerase chain reaction for qnrA, qnrB and qnrS, qepA and aac(6?)-Ib-cr genes. Conjugations were performed to assess the transferability of resistance to quinolones. Ciprofloxacin-resistant E. coli was found in 22.4% of turkey breeding flocks and 60.9% of meat flocks. Two main mutations in gyrA, as well as a range of silent mutations, were identified in resistant isolates. Flocks with transferable resistance genes qnrB, qnrS, and aac(6?)-Ib-cr were found at a low flock prevalence of 4.2%, 1.6% and 1.0%, respectively; however, under laboratory conditions only transfer of qnrS genes could be demonstrated. This work has confirmed the occurrence of ciprofloxacin-resistant E. coli strains throughout turkey breeding and meat flocks, with almost one-third of E. coli isolates being resistant to ciprofloxacin. Of those, more than 87% were also resistant to three or more antimicrobial classes.

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Section: Discussionmentioning

confidence: 99%

Ciprofloxacin resistance inE. coliisolated from turkeys in Great Britain

et al. 2012

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“…Apart from the treatment regimen (flock treatment versus individual treatment), the selection of antibiotic-resistant bacteria is influenced by factors such as the treatment dose (14,15), the number of animals housed together (16), and other management factors (17)(18)(19)(20)(21). Among these factors, mathematical modeling suggests that dose may play a particularly important role in the selection of resistant coliform bacteria following tetracycline treatment (22).…”

Section: Abstract Dose Flock Treatment Nursery Pigs Tetracyclinesmentioning

confidence: 99%

Effect of Tetracycline Dose and Treatment Mode on Selection of Resistant Coliform Bacteria in Nursery Pigs

Græsbøll

Damborg

Mellerup³

et al. 2017

Appl Environ Microbiol

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This study describes the results of a randomized clinical trial investigating the effect of oxytetracycline treatment dose and mode of administration on the selection of antibiotic-resistant coliform bacteria in fecal samples from nursery pigs. Nursery pigs (pigs of 4 to 7 weeks of age) in five pig herds were treated with oxytetracycline for Lawsonia intracellularis-induced diarrhea. Each group was randomly allocated to one of five treatment groups: oral flock treatment with a (i) high (20 mg/kg of body weight), (ii) medium (10 mg/kg), or (iii) low (5 mg/kg) dose, (iv) oral pen-wise (small-group) treatment (10 mg/kg), and (v) individual intramuscular injection treatment (10 mg/kg). All groups were treated once a day for 5 days. In all groups, treatment caused a rise in the numbers and proportions of tetracyclineresistant coliform bacteria right after treatment, followed by a significant drop by the time that the pigs left the nursery unit. The counts and proportions of tetracyclineresistant coliforms did not vary significantly between treatment groups, except immediately after treatment, when the highest treatment dose resulted in the highest number of resistant coliforms. A control group treated with tiamulin did not show significant changes in the numbers or proportions of tetracycline-resistant coliforms. Selection for tetracycline-resistant coliforms was significantly correlated to selection for ampicillin-and sulfonamide-resistant strains but not to selection for cefotaximeresistant strains. In conclusion, the difference in the dose of oxytetracycline and the way in which the drug was applied did not cause significantly different levels of selection of tetracycline-resistant coliform bacteria under the conditions tested.IMPORTANCE Antimicrobial resistance is a global threat to human health. Treatment of livestock with antimicrobials has a direct impact on this problem, and there is a need to improve the ways that we use antimicrobials in livestock production. We hypothesized that antibiotic resistance development following treatment of diarrhea in nursery pigs could be reduced either by lowering the dose of oxytetracycline or by replacing the commonly used practice of flock treatment with individual or smallgroup treatments, since this would reduce the number of pigs treated. However, the study showed no significant difference between treatment groups with respect to the number or proportion of tetracycline-resistant coliforms selected. The most important conclusion is that under practical field conditions, there will be no added value, in terms of lowering resistance development, by exchanging flock treatment for individual or small-group treatment of nursery pigs. The reason for the lack of an

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“…However, in our previous study, QREC was isolated from some farms that did not use fluoroquinolones and, in contrast, was not found on some farms that did use those agents (2). This observation, together with the findings of Taylor et al (7) and Pereira et al (6), indicates that the occurrence of QREC is not solely dependent on the use of fluoroquinolones. It is therefore possible that there are reasons other than fluoroquinolone exposure for the occurrence of QREC on dairy farms, as suggested in our previous study (3).…”

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confidence: 58%

“…Exposure to quinolone drugs is known to select for bacteria that are resistant (2,6,7). However, in our previous study, QREC was isolated from some farms that did not use fluoroquinolones and, in contrast, was not found on some farms that did use those agents (2).…”

mentioning

confidence: 70%

Occurrence and Spread of Quinolone-Resistant Escherichia coli on Dairy Farms

Duse

Waller

Emanuelson

et al. 2016

Appl Environ Microbiol

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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. IMPORTANCEThis study investigates the occurrence of a specific type of antimicrobial-resistant bacterium on dairy farms. It contributes to increased knowledge about the occurrence and spread of these bacteria, and the results pave the way for actions or further studies that could help mitigate the spread of these bacteria on dairy farms and in the community as a whole.

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Farm-level risk factors for fluoroquinolone resistance inE. coliand thermophilicCampylobacterspp. on finisher pig farms

Cited by 29 publications

References 40 publications

Ciprofloxacin resistance inE. coliisolated from turkeys in Great Britain

Ciprofloxacin resistance inE. coliisolated from turkeys in Great Britain

Effect of Tetracycline Dose and Treatment Mode on Selection of Resistant Coliform Bacteria in Nursery Pigs

Occurrence and Spread of Quinolone-Resistant Escherichia coli on Dairy Farms

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