Selection of resistant bacteria at very low antibiotic concentrations.
Erik Gullberg,Sha Cao,Otto G. Berg,Carolina Ilbäck,Linus Sandegren,Diarmaid Hughes,Dan I. Andersson +6 more
TLDR
It is suggested that the low antibiotic concentrations found in many natural environments are important for enrichment and maintenance of resistance in bacterial populations.Abstract:
The widespread use of antibiotics is selecting for a variety of resistance mechanisms that seriously challenge our ability to treat bacterial infections. Resistant bacteria can be selected at the high concentrations of antibiotics used therapeutically, but what role the much lower antibiotic concentrations present in many environments plays in selection remains largely unclear. Here we show using highly sensitive competition experiments that selection of resistant bacteria occurs at extremely low antibiotic concentrations. Thus, for three clinically important antibiotics, drug concentrations up to several hundred-fold below the minimal inhibitory concentration of susceptible bacteria could enrich for resistant bacteria, even when present at a very low initial fraction. We also show that de novo mutants can be selected at sub-MIC concentrations of antibiotics, and we provide a mathematical model predicting how rapidly such mutants would take over in a susceptible population. These results add another dimension to the evolution of resistance and suggest that the low antibiotic concentrations found in many natural environments are important for enrichment and maintenance of resistance in bacterial populations.read more
Citations
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Adaptation at different points along antibiotic concentration gradients.
TL;DR: In this paper, the authors examined the fitness of Escherichia coli at several points along a concentration gradient for three different antibiotics, asking how rapidly resistance evolved and whether populations became specialized to the antibiotic concentration they were selected on.
Journal ArticleDOI
Genetic evaluation of ESBL-producing Escherichia coli urinary isolates in Otago, New Zealand.
Isuri U Hapuarachchi,Rachel F. Hannaway,Tabatha Roman,Ambarish Biswas,Ambarish Biswas,Kristin Dyet,Xochitl C. Morgan,James E. Ussher +7 more
TL;DR: In this article, 65 urinary ESBL-producing Escherichia coli (ESBL-Ec) isolates from the Otago region in 2015 were fully genetically characterized to understand the mechanisms of transmission.
Journal ArticleDOI
Reservoir of Antibiotic Residues and Resistant Coagulase Negative Staphylococci in a Healthy Population in the Greater Accra Region, Ghana
Samuel Oppong Bekoe,Sophie Hane-Weijman,Sofie Louise Trads,Emmanuel Orman,Japheth A. Opintan,Martin Hansen,Niels Frimodt-Møller,Bjarne Styrishave +7 more
TL;DR: Although the volunteers had not knowingly consumed antibiotics two weeks before sampling, antibiotic residues were identified in 22% of urine samples, suggesting healthy individuals could be reservoirs of antibiotic residues and rCoNS at the community level.
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Tackling drug resistant infection outbreaks of global pandemic Escherichia coli ST131 using evolutionary and epidemiological genomics
TL;DR: A multi-faceted approach can enhance assessment of antimicrobial resistance in E. coli ST131 by examining transmission dynamics between hosts to achieve a goal of pre-empting resistance before it emerges by optimising antimicrobial treatment protocols.
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Effect of Exposure to Chlorhexidine Residues at "During Use" Concentrations on Antimicrobial Susceptibility Profile, Efflux, Conjugative Plasmid Transfer, and Metabolism of Escherichia coli.
TL;DR: E. coli phenotype responses to CHX exposure are concentration dependent, with realistic residual CHX concentrations resulting in stable clinical cross-resistance to antibiotics, and the findings to the risk of emerging antimicrobial resistance.
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