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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Increase in Antimicrobial Resistance in Bacteria Isolated from Stranded Marine Mammals of the Northwest Atlantic
Courtney C. Wallace,Courtney C. Wallace,Philip O. Yund,Timothy E. Ford,Keith Matassa,Keith Matassa,Anna L. Bass +6 more
TL;DR: There is an increase in resistance among common bacterial pathogens of marine mammals over a time span of 6 years, with a significant increase in multiple antimicrobial resistance in cultures from untreated animals.
Journal ArticleDOI
Antimicrobial resistance (AMR) nanomachines-mechanisms for fluoroquinolone and glycopeptide recognition, efflux and/or deactivation.
TL;DR: In this paper, the authors discuss mechanisms of resistance identified in bacterial agents Staphylococcus aureus and the enterococci towards two priority classes of antibiotics (the fluoroquinolones and the glycopeptides).
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Fitness Cost of Fluoroquinolone Resistance in Clinical Isolates of Pseudomonas aeruginosa Differs by Type III Secretion Genotype.
TL;DR: This first investigation into potential differences in fitness costs of FQ-resistance that are linked to the virulence genotype of P. aeruginosa found that exoU strains may be able to compensate for the fitness costs associated with the mutation through better regulation of supercoiling compared to the exoS strains.
Journal ArticleDOI
Cointegration as a mechanism for the evolution of a KPC-producing multidrug resistance plasmid in Proteus mirabilis
Xiaoting Hua,Linyue Zhang,Robert A Moran,Qingye Xu,Long Sun,Willem van Schaik,Yunsong Yu,Yunsong Yu +7 more
TL;DR: The importance of cointegrate plasmids in the dissemination of antibiotic resistance genes between pathogenic bacterial species is highlighted, and the importance of sub-inhibitory concentrations of antibiotics to the persistence of such plasmid-carrying cells is highlighted.
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Bacterial adaptation to sublethal antibiotic gradients can change the ecological properties of multitrophic microbial communities
TL;DR: The results show that the presence of natural enemies can modify and even reverse the effects of antibiotics on bacteria, and that antibiotic selection can change the ecological properties of multitrophic microbial communities by having indirect effects on species not directly affected by antibiotics.
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