Abstract
Isolates of the fire blight pathogen Erwinia amylovora with high-level resistance to oxytetracycline (minimal inhibitory concentration [MIC] > 100 μg/ml) and to streptomycin (MIC > 100 μg/ml) were recovered from four commercial pear orchards in California between 2018 and 2020. The two representative oxytetracycline- and streptomycin-resistant (OxyTc R -Sm R ) strains 32-10 and 33-1 were as virulent as the antibiotic susceptible strain 13-1 in causing blossom blight of pear and were recovered more than 50% of the time 7 days after co-inoculation to pear flowers with strain 13-1. In the field, inoculation of strain 32-10 to pear flowers that were pretreated with oxytetracycline at 200 μg/ml did not reduce disease compared with an untreated control. Four OxyTc R -Sm R strains were subjected to draft genome sequencing to identify the genetic determinants of antibiotic resistance and their location. A 43.6-kb IncX plasmid, designated pX11-7, was detected in each of the four strains, and this plasmid encoded the tetracycline-resistance gene tetB and the streptomycin-resistance gene pair strAB within a large putatively mobile genetic element consisting of the transposon Tn 10 that had inserted within the streptomycin-resistance transposon Tn 6082. We also determined that pX11-7 was conjugative and was transferred at a rate that was 10 4 to 10 5 higher into an E. amylovora strain isolated in California compared with an E. amylovora strain that was isolated in Michigan. The occurrence of high levels of resistance to both oxytetracycline and streptomycin in E. amylovora strains from commercial pear orchards in California significantly limits the options for blossom blight management in these locations.
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Claims 8
Claim · model-written summary
Resistant E. amylovora isolates occurred in four California pear orchards.
- Taxon
- pear
_Poirier_Fleurs_et_feuilles.jpg?width=60)
Pyrus communise0 - Interactor
- Erwinia amylovora
Erwinia amylovorae0pathogen - Outcome
- high-level resistance to oxytetracyclinee0
- Value
- > 100 μg/mle0
- Setting
- Californiae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_Poirier_Fleurs_et_feuilles.jpg?width=500)
Verbatim
e0“Isolates of the fire blight pathogen Erwinia amylovora with high-level resistance to oxytetracycline (minimal inhibitory concentration [MIC] > 100 μg/ml) and to streptomycin (MIC > 100 μg/ml) were recovered from four commercial pear orchards in California between 2018 and 2020”
Claim · model-written summary
Resistant strains caused pear blossom blight as virulently as susceptible strain 13-1.
- Taxon
- pearPyrus communise0
- Interactor
- strains 32-10 and 33-1e0pathogen
- Outcome
- blossom blighte0
- Direction
- as virulente0
- Comparator
- antibiotic susceptible strain 13-1e0
Not reportedMaterial
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“strains 32-10 and 33-1 were as virulent as the antibiotic susceptible strain 13-1 in causing blossom blight of pear”
Claim · model-written summary
Resistant strains were recovered over half the time after co-inoculation to pear flowers.
- Taxon
- pearPyrus communise0
- Organ / stage
- flowerse0
- Interactor
- strain 13-1e0pathogen
- Outcome
- recoverede0
- Value
- more than 50% of the timee0
- Qualifier
- 7 days after co-inoculatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“were recovered more than 50% of the time 7 days after co-inoculation to pear flowers with strain 13-1”
Claim · model-written summary
Oxytetracycline pretreatment did not reduce blossom disease after resistant strain inoculation.
- Taxon
- pearPyrus communise0
- Organ / stage
- flowerse0
- Treatment
- oxytetracycline at 200 μg/mle0
- Interactor
- strain 32-10e0pathogen
- Outcome
- diseasee0
- Direction
- did not reducee0
- Comparator
- untreated controle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“inoculation of strain 32-10 to pear flowers that were pretreated with oxytetracycline at 200 μg/ml did not reduce disease compared with an untreated control”
Claim · model-written summary
A 43.6-kb IncX plasmid carrying tetracycline and streptomycin resistance genes was found in each resistant strain.
- Taxon
- pearPyrus communist0
- Interactor
- four strainse0pathogen
- Gene
- pX11-7e0
- Outcome
- IncX plasmide0
- Value
- 43.6-kbe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A 43.6-kb IncX plasmid, designated pX11-7, was detected in each of the four strains, and this plasmid encoded the tetracycline-resistance gene tetB and the streptomycin-resistance gene pair strAB”
t0“pear”
Claim · model-written summary
Plasmid pX11-7 was conjugative.
- Taxon
- pearPyrus communist0
- Gene
- pX11-7e0
- Outcome
- conjugativee0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“pX11-7 was conjugative”
t0“pear”
Claim · model-written summary
Plasmid transfer was 10 4 to 10 5 higher to a California than Michigan E. amylovora strain.
- Taxon
- pearPyrus communist0
- Interactor
- E. amylovoraErwinia amylovorae0pathogen
- Outcome
- transferred at a ratee0
- Direction
- highere0
- Value
- 10 4 to 10 5e0
- Comparator
- E. amylovora strain that was isolated in Michigane0
- Setting
- Californiae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“transferred at a rate that was 10 4 to 10 5 higher into an E. amylovora strain isolated in California compared with an E. amylovora strain that was isolated in Michigan”
t0“pear”
Claim · model-written summary
The authors conclude that dual antibiotic resistance limits pear blossom blight management options in California orchards.
- Taxon
- pearPyrus communise0
- Interactor
- E. amylovoraErwinia amylovorae0pathogen
- Outcome
- options for blossom blight managemente0
- Setting
- Californiae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“occurrence of high levels of resistance to both oxytetracycline and streptomycin in E. amylovora strains from commercial pear orchards in California significantly limits the options for blossom blight management in these locations”
The same questions in other papers
oxytetracycline · disease · Pyrus communis (pear)Positive and negative results
2 in the opposite direction
- positive
- positive
Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.