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allied
academies
Journal of Microbiology: Current Research | Volume 2
November 01-02, 2018 | London, UK
7
th
European
Clinical Microbiology Congress
4
th
International Conference on
Ophthalmology and Eye Disorder
Joint Event
&
Notes:
Evolution of high-level aminoglycoside resistance in
Escherichia coli
under high and low mutation
supply rates
Claudia Ibacache-Quiroga
National Center for Biotechnology, Spain
A
ntibiotic resistance is a major concern in public health
worldwide,generating25,000deathperyearonlyinEurope,
thus there is much interest in characterizing the mutational
pathways through which susceptible bacteria evolve resistance.
Amongmostimportantantibioticsinhumanhealtharethosethat
belong to the aminoglycoside family, whose are effective for the
treatment of infections caused by gram negative pathogens like
Escherichia coli. The usage of experimental evolution to explore
the mutational pathways toward aminoglycoside resistance,
using gentamicin as a model, under low and high mutation
supply rates, allowed to identify that normo and hypermutable
strains of
Escherichia coli
are able to develop resistance to
drug dosages > 1,000 fold higher than the minimal inhibitory
concentration for their ancestors. In this approach, this level of
resistance has been associated with changes in susceptibility
to other antibiotics. Whole-genome sequencing of gentamicin-
resistant strains revealed that all resistant derivatives presented
diverse mutations in five common genetic elements: fhuA, fusA
and the atpIBEFHAGDC, cyoABCDE and potABCD operons. In
contrast to recent studies, in this study themutation supply rate
mainly affected the speed (tempo) but not the pattern (mode)
of evolution: Both backgrounds acquired the mutations in the
same order, although the hypermutator strain did it faster.
This observation is compatible with the adaptive landscape
for high-level gentamicin resistance being relatively smooth,
with few local maxima; which might be a common feature
among antibiotics for which resistance involves multiple loci.
e:
claudia.ibacache@uv.clClinical Microbiology and Eye 2018, Volume 2
DOI: 10.4066/2591-8036-C1-003