The evolution of resistant bacteria
A European study investigated the mechanisms by which antibiotic-resistant bacteria evolve. The genetic determinants of this process could have important implications for the spread of microbial resistance.
Bacterial resistance to antibiotics is a major hurdle for fighting many
infections. Numerous research efforts try to address the problem by
identifying novel targets and synthesising new compounds with
antimicrobial function.
Equally important, however, is understanding the evolutionary and
genetic factors that drive the emergence and spread of resistant
pathogens. In this context, the EU-funded 'Specificity of antibiotic
resistance evolution' (SPECRESEVO) project set out to elucidate how
resistance is affected during evolution and in different environments.
Partners isolated resistant bacteria experimentally using
conventional protocols and subjected them to different growth
conditions. Additionally, they isolated bacteria with a different
history of antibiotic exposure to find that the effect of mutations
associated with resistance is largely dependent on the environment and
the genetic background. Therefore, we need to understand these
mechanisms first before we can predict bacterial spread and minimise
antibiotic resistance.
Furthermore, partners studied how resistant bacteria grow in the
absence of antibiotic pressure. Resistant bacteria continued to have an
increased fitness, compared to normal species, without reverting to drug
sensitivity, clearly underscoring the necessity of genetic studies to
identify the implicated loci. This competitive fitness was
mutation-specific and also depended on the genetic background of the
pathogen.
SPECRESEVO work proved the principle that experimental microbial
evolution is a valid approach for determining key aspects related to
antibiotic resistance. Collectively, the generated information sheds
light onto the complex process of resistance-mediated fitness and
suggests avenues to prohibit resistant bacterial spread. Long-term, this
is expected to improve health care and minimise related costs.
published: 2015-02-11