scholarly journals Conyza sumatrensis Resistant to Paraquat, Glyphosate and Chlorimuron: Confirmation and Monitoring the First Case of Multiple Resistance in Paraguay

Agriculture ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 582
Author(s):  
Alfredo Junior Paiola Albrecht ◽  
Guilherme Thomazini ◽  
Leandro Paiola Albrecht ◽  
Afonso Pires ◽  
Juliano Bortoluzzi Lorenzetti ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Herbicide Resistance ◽  
Multiple Drug Resistance ◽  
Population Monitoring ◽  
Multiple Drug ◽  
Multiple Resistance ◽  
Growth Reduction ◽  
Herbicide Application ◽  
Response Curves ◽  
First Case

Conyza sumatrensis was reported to be associated with 20 cases of herbicide resistance worldwide, with a recent report of multiple drug resistance to paraquat, glyphosate, and chlorimuron in Brazil. In Paraguay, there were no reports of cases of resistance for this species; however, in 2017, researchers began identifying biotypes with resistance to paraquat, glyphosate, and chlorimuron, which is the focus of the present study. The goal of this study was to investigate the case of multiple resistance of C. sumatrensis to paraquat, glyphosate, and chlorimuron and to monitor the resistant biotypes in the departments of Canindeyú and Alto Paraná. Seeds were collected from sites where plants survived after herbicide application in the 2017/18 and 2018/19 seasons. After screening, biotypes were selected for the construction of dose–response curves. A resistance factor (RF) of 6.79 was observed for 50% control (C50) and 3.92 for 50% growth reduction (GR50) for the application of paraquat. An RF of 12.32 was found for C50 and 4.15 for GR50 for the application of glyphosate. For the application of chlorimuron, an RF of 11.32 was found for C50 and 10.96 for GR50. This confirms the multiple resistance of the C. sumatrensis biotype to paraquat, glyphosate, and chlorimuron. Population monitoring indicated the presence of C. sumatrensis with multiple resistance in departments of Canindeyú and Alto Paraná, Paraguay.

scholarly journals Diversity of plasmids responsible for multiple resistance in klebsiella serotype K2

1981 ◽  
Vol 86 (2) ◽  
pp. 189-194 ◽  
Author(s):  
Hilary Richards ◽  
Victoria Hughes ◽  
Naomi Datta
Keyword(s):  
Drug Resistance ◽  
Multiple Drug Resistance ◽  
Multiple Drug ◽  
Multiple Resistance ◽  
Capsular Type ◽  
Epidemic Clone ◽  
Resistance Plasmids ◽  
Bacterial Clone ◽  
Serotype K2

SUMMARYKlebsiella of capsular type K2 were investigated to find out whether a single epidemic clone was the source of many outbreaks of infection in different hospitals, in different areas over a period of five years. The klebsiellas studied were found to be very similar; they were of the same biotype, had similar klebecin sensitivity patterns and carried multiple drug-resistance plasmids; however, characterization of these plasmids showed that they were heterogeneous. Thus there was not a single epidemic bacterial clone.

Do Multiple Drug Resistance Transporters Interfere with Cell Functioning under Normal Conditions?

2020 ◽  
Vol 85 (12-13) ◽  
pp. 1560-1569
Author(s):  
D. A. Knorre ◽  
K. V. Galkina ◽  
T. Shirokovskikh ◽  
A. Banerjee ◽  
R. Prasad
Keyword(s):  
Drug Resistance ◽  
Multiple Drug Resistance ◽  
Multiple Drug

scholarly journals Amelioration of the Cost of Conjugative Plasmid Carriage in Eschericha coli K12

Genetics ◽  
2003 ◽  
Vol 165 (4) ◽  
pp. 1641-1649
Author(s):  
Cecilia Dahlberg ◽  
Lin Chao
Keyword(s):  
Drug Resistance ◽  
Multiple Drug Resistance ◽  
Conjugative Plasmid ◽  
Energetic Cost ◽  
Multiple Drug ◽  
Genetic Changes ◽  
Batch Cultures ◽  
Transfer Rates ◽  
Bacterial Plasmid ◽  
The Cost

Abstract Although plasmids can provide beneficial functions to their host bacteria, they might confer a physiological or energetic cost. This study examines how natural selection may reduce the cost of carrying conjugative plasmids with drug-resistance markers in the absence of antibiotic selection. We studied two plasmids, R1 and RP4, both of which carry multiple drug resistance genes and were shown to impose an initial fitness cost on Escherichia coli. To determine if and how the cost could be reduced, we subjected plasmid-containing bacteria to 1100 generations of evolution in batch cultures. Analysis of the evolved populations revealed that plasmid loss never occurred, but that the cost was reduced through genetic changes in both the plasmids and the bacteria. Changes in the plasmids were inferred by the demonstration that evolved plasmids no longer imposed a cost on their hosts when transferred to a plasmid-free clone of the ancestral E. coli. Changes in the bacteria were shown by the lowered cost when the ancestral plasmids were introduced into evolved bacteria that had been cured of their (evolved) plasmids. Additionally, changes in the bacteria were inferred because conjugative transfer rates of evolved R1 plasmids were lower in the evolved host than in the ancestral host. Our results suggest that once a conjugative bacterial plasmid has invaded a bacterial population it will remain even if the original selection is discontinued.

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