Feb. 20, 2013
http://www.sciencedaily.com/releases/2013/02/130221194045.htm
Summary:
When
bacteria are stressed, they become resistant to antibiotics. Biologists tested and realized that E. Coli
grown in high temperatures become resistant to rifampicin. In the absence of antibiotics, non-resistant
bacteria will out-compete the resistant ones.
Researchers from UC Irvine and Faculté de Médicine Denis Diderot have
discovered that by putting bacteria under stress and by growing them at a high
temperature, the bacteria could spontaneously develop resistance to the
antibiotic rifampicin. After their
studies, scientists concluded that antibiotic resistance can occur even in the
absence of antibiotics and that, depending on the type of bacteria, and growth
conditions, rather than being costly to maintain can be highly beneficial. This discovery would be beneficial to puplic
health. These bacteria provide strong
evidence that the evolution of antibiotic resistance is governed by two
properties of genes; pleiotropy and epistasis.
Pleiotropy describes how the antibiotic resistance mutations affect
other functions, hence their fate in other environments. Epistasis describes
how well different mutations combine in their effect on resistance, and
therefore determines which mutational pathway will be preferred by evolution
when several mutations are needed for full resistance.
Connection:
This is relavent to our previous lesson about the elovlution of antibiotic resistance in bacteria. We learned that antibiotic resistance evolves by natural selection. Those bacteria that are resistant to antibiotics survives while the others die. This evolution of antibiotic resistant bacteria was one of the main problems in public heath. It was very important for doctors to prescribe the right antibiotics. However, with this discovery it might not be too complicated.
What does the antibiotic rifampcin target in bacteria so the pathogen dies?
ReplyDeleteRifampicin targets a bacterial chemical called RNA-polymerase. The pathogen use RNA-polymerase to make essential proteins and to copy their own genetic information (DNA). Without this chemical the bacteria cannot reproduce and they die.
DeleteWhy is it that in the absence of antibiotics, the non-resistant bacteria will out compete the resistant bacteria? What advantages do the non-resistant bacteria have?
ReplyDelete