Features | Partner Sites | Information | LinkXpress
Sign In
GLOBETECH PUBLISHING LLC
GLOBETECH PUBLISHING LLC
GLOBETECH MEDIA

Bacterial Populations Rapidly Evolve a Time-linked Tolerance to Antibiotics

By BiotechDaily International staff writers
Posted on 14 Jul 2014
A team of molecular microbiologists has found that some types of bacteria develop tolerance towards antibiotic treatment by "learning" how to time the length of exposure to the drug and evolving an extended period of dormancy that protects the organisms from the effects of the antibiotic.

Investigators at the Hebrew University of Jerusalem (Israel) followed the evolution of bacterial populations under intermittent exposure to the high concentrations of antibiotics used in the clinic and characterized the evolved strains in terms of both resistance (growth of microorganisms in the constant presence of an antibiotic, provided that the concentration of the antibiotic is not too high) and tolerance (survival of microorganisms during antibiotic treatment, even at high antibiotic concentrations, as long as the duration of the treatment is limited).

Initially bacterial populations were treated with antibiotics for three hours each day. Exposure times were later increased to five and eight hours per day.

By monitoring the phenotypic changes at the population and single-cell levels, the investigators found that after only 10 days the first adaptive change to antibiotic stress became apparent. This was the development of tolerance towards the antibiotic through a major adjustment in the single-cell lag-time distribution, without a change in resistance. They also found that the lag time of bacteria before regrowth was optimized to match the duration of the antibiotic-exposure interval. All bacterial strains adapted by specific genetic mutations, which became fixed in the evolved populations.

The investigators also reported that whole genome sequencing of the evolved strains and restoration of the wild-type alleles allowed the identification of target genes involved in this antibiotic-driven phenotype, which they called "tolerance by lag" (tbl).

The results of this study, which was published in the June 25, 2014, online edition of the journal Nature, demonstrated that bacteria can evolve within days. The investigators expect that better understanding of lag-time evolution as a key determinant of the survival of bacterial populations under high antibiotic concentrations will lead to new approaches to preventing the evolution of antibiotic resistance.

Related Links:

Hebrew University of Jerusalem



Channels

Biochemistry

view channel

Possible New Target Found for Treating Brain Inflammation

Scientists have identified an enzyme that produces a class of inflammatory lipid molecules in the brain. Abnormally high levels of these molecules appear to cause a rare inherited eurodegenerative disorder, and that disorder now may be treatable if researchers can develop suitable drug candidates that suppress this enzyme.... Read more

Therapeutics

view channel
Image: Cancer cells infected with tumor-targeted oncolytic virus (red). Green indicates alpha-tubulin, a cell skeleton protein. Blue is DNA in the cancer cell nuclei (Photo courtesy of Dr. Rathi Gangeswaran, Bart’s Cancer Institute).

Innovative “Viro-Immunotherapy” Designed to Kill Breast Cancer Cells

A leading scientist has devised a new treatment that employs viruses to kill breast cancer cells. The research could lead to a promising “viro-immunotherapy” for patients with triple-negative breast cancer,... Read more

Lab Technologies

view channel
Image: MIT researchers have designed a microfluidic device that allows them to precisely trap pairs of cells (one red, one green) and observe how they interact over time (Photo courtesy of Burak Dura, MIT).

New Device Designed to See Communication between Immune Cells

The immune system is a complicated network of many different cells working together to defend against invaders. Effectively combating an infection depends on the interactions between these cells.... Read more

Business

view channel

Program Designed to Provide High-Performance Computing Cluster Systems for Bioinformatics Research

Dedicated Computing (Waukesha, WI, USA), a global technology company, reported that it will be participating in the Intel Cluster Ready program to deliver integrated high-performance computing cluster solutions to the life sciences market. Powered by Intel Xeon processors, Dedicated Computing is providing a range of... Read more
 
Copyright © 2000-2015 Globetech Media. All rights reserved.