Antibiotic Resistance, Author Interviews, Infections, Science / 04.01.2015
Cholera Bacteria Kills Neighbors To Acquire Antibiotic Resistance Genes
MedicalResearch.com Interview with:
Melanie Blokesch PhD
Assistant Professor (tenure-track)
Laboratory of Molecular Microbiology
Global Health Institute, School of Life Sciences
Swiss Federal Institute of Technology Lausanne (EPFL)
Lausanne Switzerland
Medical Research: What is the background for this study? What are the main findings?
Dr. Blokesch: We have been studying the cholera-causing bacterium Vibrio cholerae for many years in my laboratory. Our main focus has always been on elucidating how this pathogen acquires new genetic material that allows it to evolve. This is often accomplished through a mechanism known as horizontal gene transfer (HGT). There are three main modes of horizontal gene transfer in bacteria and the one we are primarily interested in is called natural competence for transformation. When the bacterium enters the state of natural competence it can take up free genetic material from its surrounding and in case it recombines this new material into its own genome the bacterium is considered to be naturally transformed. Notably, natural competence/transformation was first described in 1928 by Fred Griffith, who showed that transformation can render harmless bacteria pathogenic. These early experiments can be considered a milestone in molecular biology as it later led to the discovery of DNA as the carrier of genetic information.
Medical Research: What are the main findings?
Dr. Blokesch: The main finding of our study is that the pathogen V. cholerae does not solely rely on free DNA floating around but that it actively kills neighbouring bacteria followed by the uptake of their DNA. Indeed, we were able to show that the two processes - killing of other bacteria and DNA uptake - are co-regulated by the same proteins within the bacterial cell. We also used imaging techniques to visualize the killing of other bacteria by V. cholerae, followed by the release of their genetic material, which the predator then pulled into its own cell. We further quantified these HGT events by following the transfer of an antibiotic resistance gene from the killed bacterium to the predatory V. cholerae cell. Notably, the spread of antibiotic resistances is a major health concern and HGT is a major driver of it.
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