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"Morley, Katy"
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Evidence that faecal carriage of resistant Escherichia coli by 16-week-old dogs in the United Kingdom is associated with raw feeding
2021
We report a survey (August 2017 to March 2018) and risk factor analysis of faecal carriage of antibacterial-resistant (ABR) Escherichia coli in 223 sixteen-week-old dogs in the United Kingdom. Raw feeding was associated with the presence of E. coli resistant to fluoroquinolones, tetracycline, amoxicillin, and streptomycin, but not to cefalexin or cefotaxime. Whole genome sequencing of 30 fluoroquinolone-resistant (FQ-R), 22 cefotaxime-resistant (CTX-R) and seven dual FQ-R/CTX-R E. coli isolates showed a wide range of sequence types (STs), an approximately 50:50 split of CTX-M:AmpC-mediated CTX-R, and almost exclusively mutational FQ-R dominated by ST744 and ST162. Comparisons between E. coli isolates from puppies known to be located within a 50 x 50 km region with those isolated from human urinary tract and bloodstream infections (isolated in parallel in the same region) identified a clone of ST963 E. coli carrying chromosomal blaCMY-2 in two puppies and causing two urinary tract infections and one bloodstream infection. Furthermore, an ST744 FQ-R clone was carried by one puppy and caused one urinary tract infection. Accordingly, we conclude that raw feeding is associated with carriage of ABR E. coli in dogs even at sixteen weeks of age and that bacteria carried by these dogs are shared with humans and cause serious opportunistic infections. We therefore suggest that those who feed their dogs raw meat seriously consider the potential ABR-transmission threat their pet may become as a result and deploy appropriate hygiene practices in mitigation. Competing Interest Statement The authors have declared no competing interest.
Molecular epidemiology of Escherichia coli producing CTX-M and plasmid AmpC-type β-lactamases from dairy farms identifies a dominant plasmid encoding CTX-M-32 but no evidence for transmission to humans in the same geographical region
2020
Third-generation cephalosporin resistance (3GC-R) in Escherichia coli is a rising problem in human and farmed animal populations. We conducted whole genome sequencing analysis of 138 representative 3GC-R isolates previously collected from dairy farms in South West England and confirmed by PCR to carry acquired 3GC-R genes. This analysis identified blaCTX-M (131 isolates: encoding CTX-M-1, −14, −15, −32 and the novel variant, CTX-M-214), blaCMY-2 (6 isolates) and blaDHA-1 (one isolate). A highly conserved plasmid was identified in 73 isolates, representing 27 E. coli sequence types. This novel ~220 kb IncHI2 plasmid carrying blaCTX-M-32 was sequenced to closure and designated pMOO-32. It was found experimentally to be stable in cattle and human transconjugant E. coli even in the absence of selective pressure and was found by multiplex PCR to be present on 26 study farms representing a remarkable range of transmission over 1500 square kilometres. However, the plasmid was not found amongst human urinary E. coli we have recently characterised from people living in the same geographical location, collected in parallel with farm sampling. There were close relatives of two blaCTX-M plasmids circulating amongst eight human and two cattle isolates, and a closely related blaCMY-2 plasmid found in one cattle and one human isolate. However, phylogenetic evidence of recent sharing of 3GC-R strains between farms and humans in the same region was not found.
Third-generation cephalosporins (3GCs) are critically important antibacterials and 3GC-resistance (3GC-R) threatens human health, particularly in the context of opportunistic pathogens such as Escherichia coli. There is some evidence for zoonotic transmission of 3GC-R E. coli through food, but little work has been done examining possible transmission (e.g. via interaction of people with the local near-farm environment). We characterised acquired 3GC-R E. coli found on dairy farms in a geographically restricted region of the United Kingdom and compared these with E. coli from people living in the same region, collected in parallel. Whilst there is strong evidence for recent farm-to-farm transmission of 3GC-R strains and plasmids – including one epidemic plasmid that has a remarkable capacity to transmit – there was no evidence that 3GC-R found on study farms had a significant impact on circulating 3GC-R E. coli strains or plasmids in the local human population.
Limited Phylogenetic Overlap Between Fluoroquinolone-Resistant Escherichia coli Isolated on Dairy Farms and those Causing Bacteriuria in Humans Living in the Same Geographical Region
2021
Our primary aim was to test whether cattle-associated fluoroquinolone-resistant (FQ-R) Escherichia coli found on dairy farms were a significant cause of bacteriuria in humans living in the same 50 × 50 km geographical region located in South West England. Another aim was to identify risk factors for the presence of FQ-R E. coli on dairy farms.
FQ-R E. coli were isolated during 2017-18 from 42 dairy farms and from community urine samples. Forty-two cattle and 489 human urinary isolates were subjected to WGS, allowing phylogenetic comparisons. Risk factors were identified using a Bayesian regularisation approach.
Of 489 FQ-R human isolates, 255 were also 3rd generation cephalosporin-resistant (3GC-R), with strong genetic linkage between aac(6’)Ib-cr and blaCTX-M-15. We identified possible farm-to-human sharing for pairs of ST744 and ST162 isolates, but core genome SNP distances (71 and 63, respectively) were smaller in pairs of ST744 and ST162 isolates from different farms (7 and 3 SNPs, respectively). Total farm fluoroquinolone use showed a positive association with the odds of isolating FQ-R E. coli while total dry cow therapy use showed a negative association.
This work suggests that FQ-R E. coli found on dairy farms have a limited impact on community bacteriuria within the local human population, however, this appears greater than observed for 3GC-R E. coli when studied in parallel. Reducing fluoroquinolone use may reduce the on-farm prevalence of FQ-R E. coli, and this reduction may be greater when dry cow therapy is targeted to the ecology of resistant E. coli on the farm.
Reduced antibacterial drug resistance and blaCTX-M β-lactamase gene carriage in cattle-associated Escherichia coli at low temperatures, at sites dominated by older animals and on pastureland: implications for surveillance
2020
Little is known about the drivers of critically important antibacterial resistance in species with zoonotic potential present on farms (e.g. CTX-M □-lactamase-positive Escherichia coli). Here, we collected samples, monthly over a two-year period, on 53 dairy farms in the South West of England, and data for 610 variables concerning antimicrobial usage, management practices and meteorological factors. We detected E. coli resistant to amoxicillin, ciprofloxacin streptomycin and tetracycline, respectively, in 2754/4145 (66%), 263/4145 (6%), 1475/4145 (36%) and 2874/4145 (69%) of all samples from faecally contaminated sites. E. coli positive for blaCTX-M were detected in 224/4145 (5.4%) of samples. Multilevel, multivariable logistic regression showed antibiotic dry cow therapeutic choice (including use of cefquinome or framycetin) to be associated with increased odds of blaCTX-M positivity. Low temperature was associated with reduced odds of blaCTX-M E. coli positivity in samples and to reduced odds of finding E. coli resistant to each of the four test antibacterials. This was additional to the effect of temperature on total E. coli density. Furthermore, samples collected close to calves had increased odds of having E. coli resistance to each antibacterial or positive for blaCTX-M. Samples collected on pastureland had reduced odds of having E. coli resistant to amoxicillin or tetracycline, and being positive for blaCTX-M.
Antibacterial resistance poses a significant threat to human and animal health and global food security. Surveillance for resistance on farms is important for many reasons, including to track the impacts of interventions aimed at reducing the prevalence of resistance. In this epidemiological survey of dairy farm antibacterial resistance, we show that local temperature, as it changes over the course of a year, is associated with the prevalence of antibacterial resistant E. coli. Also, that prevalence of resistant E. coli is higher in indoor environments and in environments inhabited by young animals. These findings have profound implications for routine surveillance and for surveys carried out for research. They provide important evidence that sampling at a single time-point and/or single location on a farm is unlikely to be adequate to accurately determine the status of the farm with regard to the presence or number of resistant E. coli.
Fluoroquinolone-Resistant Escherichia coli Originating on Dairy Farms are an Infrequent Cause of Bacteriuria in Humans Living in the Same Geographical Region
by
Schubert, Hannah
,
Bowker, Karen E
,
Williams, Martin
in
Bacteriuria
,
Bayesian analysis
,
Dairy farms
2021
Background: Our primary aim was to test whether cattle-associated fluoroquinolone-resistant (FQ-R) Escherichia coli found on dairy farms were a significant cause of bacteriuria in humans living in the same 50 x 50 km geographical region located in South West England. Another aim was to identify risk factors for the presence of FQ-R E. coli on dairy farms. Methods: FQ-R E. coli were isolated during 2017-18 from 42 dairy farms and from community urine samples. Forty-two cattle and 489 human urinary isolates were subjected to WGS, allowing phylogenetic comparisons. Risk factors were identified using a Bayesian regularisation approach. Results: Of 489 FQ-R human isolates, 255 were also 3rd generation cephalosporin-resistant (3GC-R), with strong genetic linkage between aac(6')Ib-cr and blaCTX-M-15. We identified possible farm-to-human sharing for pairs of ST744 and ST162 isolates, but core genome SNP distances (71 and 63, respectively) were smaller in pairs of ST744 and ST162 isolates from different farms (7 and 3 SNPs, respectively). Total farm fluoroquinolone use showed a positive association with the odds of isolating FQ-R E. coli while total dry cow therapy use showed a negative association. Conclusions: This work suggests that FQ-R E. coli found on dairy farms have a limited impact on community bacteriuria within the local human population, however, this appears greater than observed for 3GC-R E. coli when studied in parallel. Reducing fluoroquinolone use may reduce the on-farm prevalence of FQ-R E. coli, and this reduction may be greater when dry cow therapy is targeted to the ecology of resistant E. coli on the farm. Competing Interest Statement D.C.B. was president of the British Cattle Veterinary Association 2018-19. Otherwise, the authors declare no competing interests. Farming and veterinary businesses who contributed data and permitted access for sample collection were not involved in the design of this study or in data analysis and were not involved in drafting the manuscript for publication.
Molecular epidemiology of cefotaxime-resistant Escherichia coli from dairy farms in South West England identifies a dominant plasmid encoding CTX-M-32
2019
Objectives: The objective of this study was to identify the mechanisms of cefotaxime resistance (CTX-R) in 1226 Escherichia coli from 4581 environmental samples collected on 53 dairy farms over a 2-year period in South West England and to characterise a blaCTX-M-32-producing plasmid, pMOO-32, found to be widely distributed. Methods: CTX-R isolates were identified using MIC breakpoint agar plates. β-lactamase genes of interest (GOIs) were detected by PCR. WGS was performed and analysed using the Center for Genomic Epidemiology platform. A plasmid-specific multiplex PCR was designed to indicate the presence of plasmid pMOO-32. Results: Amongst 1226 CTX-R isolates, PCR identified blaCTX-M group 1 (549 isolates), blaCTX-M group 9 (100 isolates), blaCMY (12 isolates), blaDHA (1 isolate) and no GOI (566 isolates). WGS analysis of 184 representative isolates identified blaCTX-M (131 isolates; encoding CTX-M-1, -14, -15, -32 and the novel variant, CTX-M-214), blaCMY-2 (6 isolates), blaDHA-1 (one isolate) and presumed AmpC-hyperproduction in 46 isolates that were PCR negative for GOIs. A highly conserved plasmid was identified in 73 isolates, representing 27 E. coli STs. This ~220 kb IncHI2 plasmid carrying blaCTX-M-32 was designated pMOO-32, was found to be stable in cattle and human transconjugant E. coli even in the absence of selective pressure, and was found by multiplex PCR to be present on 26/53 study farms. Conclusions: β-lactamases capable of conferring resistance to third generation cephalosporins were evident on 47/53 farms within this study. This was largely because of the widespread dissemination of an IncHI2 plasmid carrying blaCTX-M-32.
Evidence for reduced CTX-M carriage in cattle-associated Escherichia coli at low temperatures and on publicly accessible farmland: implications for surveillance and potential for farm-to-human transmission
2019
Little is known about the drivers of critically important antibacterial resistance in species with zoonotic potential present on farms (e.g. CTX-M β-lactamase-positive Escherichia coli). There is also debate about the influence of farms on the circulation of resistance in local human populations. This was a two-year surveillance study on 53 dairy farms. E. coli positive for blaCTX-M were detected in 224/4145 (5.4%) of all samples from faecally-contaminated sites. E. coli positive for blaCTX-M were more prevalent (98/631; 15.5%) in calf samples and less prevalent (12/630; 1.9%) in samples collected from pastureland, including publicly accessible sites. Multilevel, multivariable logistic regression showed antibiotic dry cow therapeutic choice to be associated with risk of blaCTX-M positivity, including use of cefquinome or framycetin; 74% of blaCTX-M-positive E. coli were framycetin-resistant. Low temperature was associated with low risk of blaCTX-M positivity. This was additional to the effect of temperature on total E. coli density, a finding with profound implications for surveillance. There was no evidence that study farms had a significant impact on circulating blaCTX-M plasmids in the local human population: across 296 fully sequenced E. coli isolates, two cattle isolates shared blaCTX-M plasmids with eight urinary isolates collected in parallel.
PICASO 4.0: Clouds and Photochemistry in Climate Models of Brown Dwarfs and Exoplanets
by
Gao, Peter
,
Batalha, Natasha E
,
Chubb, Katy L
in
Atmosphere
,
Atmospheric chemistry
,
Brown dwarf stars
2026
We present a major update to the open-source atmospheric modeling package PICASO, designed for simulating the thermal structure and spectra of hydrogen-rich atmospheres of brown dwarfs and exoplanets. This release, PICASO 4.0, expands upon the existing radiative-convective equilibrium model framework by incorporating several new capabilities. Key additions include the integration of Virga for self-consistent cloud modeling, new flexible treatments for rainout and cold trapping of volatile species, and support for photochemistry. We also introduce a parameterized energy injection scheme to simulate additional external or internal heating processes. These features are motivated by lessons from recent JWST observations that reveal the prevalence of nonequilibrium chemistry and clouds. We benchmark the new functionalities against previously published results in the literature, including the Sonora Diamondback grid, energy injected atmospheres, patchy cloud models, and other photochemical models of WASP-39b. PICASO continues to be actively developed as an open-source package aimed at enabling reproducible, community-driven atmospheric modeling of all substellar objects.
Journal Article
Differentiation of lymphocytic-plasmacytic enteropathy and small cell lymphoma in cats using histology-guided mass spectrometry
2020
Abstract
Background
Differentiation of lymphocytic-plasmacytic enteropathy (LPE) from small cell lymphoma (SCL) in cats can be challenging.
Hypothesis/Objective
Histology-guided mass spectrometry (HGMS) is a suitable method for the differentiation of LPE from SCL in cats.
Animals
Forty-one cats with LPE and 52 cats with SCL.
Methods
This is a retrospective clinicopathologic study. Duodenal tissue samples of 17 cats with LPE and 22 cats with SCL were subjected to HGMS, and the acquired data were used to develop a linear discriminate analysis (LDA) machine learning algorithm. The algorithm was subsequently validated using a separate set of 24 cats with LPE and 30 cats with SCL. Cases were classified as LPE or SCL based on a consensus by an expert panel consisting of 5-7 board-certified veterinary specialists. Histopathology, immunohistochemistry, and clonality testing were available for all cats. The panel consensus classification served as a reference for the calculation of test performance parameters.
Results
Relative sensitivity, specificity, and accuracy of HGMS were 86.7% (95% confidence interval [CI]: 74.5%-98.8%), 91.7% (95% CI: 80.6%-100%), and 88.9% (95% CI: 80.5%-97.3%), respectively. Comparatively, the clonality testing had a sensitivity, specificity, and accuracy of 85.7% (95% CI: 72.8%-98.7%), 33.3% (95% CI: 14.5%-52.2%), and 61.5% (95% CI: 48.3%-74.8%) relative to the panel decision.
Conclusions and Clinical Importance
Histology-guided mass spectrometry was a reliable technique for the differentiation of LPE from SCL in duodenal formalin-fixed paraffin-embedded samples of cats and might have advantages over tests currently considered state of the art.
Journal Article
Jake
2012
At age two, Jake Barnett was diagnosed with autism and his future was unclear. Now at age 13, Jake is a college sophomore and a math and science prodigy. Jake says his autism is key to his success. Morley Safer reports.
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