Category: Antimicrobial Resistance
The journey of a superbug gene to the Arctic
By Ananya Sen
A straight walk from India to the Arctic is approximately 4,000 miles. The trip includes the hot and humid climate of India, the temperate and dry climate of central Europe, and finally the rugged and frozen tundra of Svalbard in the Arctic Circle. Imagine embarking on this adventure as a gene. Seem unlikely? Yet, a recent study from a team of researchers led by David Graham at Newcastle University describes a gene from a superbug that has made the journey.
Superbugs are bacteria that have developed resistance to most antibiotics; they remain unaffected by the antibiotics that have been designed to kill them. Bacteria that produce carbapenemases are commonly referred to as “superbugs” since carbapenems are drugs that are used as a last resort after all other options have been exhausted. Bacteria evolve to resist the overused antibiotics and can spread the mechanism of resistance to other bacteria, generating several different types of superbugs. Unfortunately, the more we overuse or misuse antibiotics, the more opportunities pathogens have to become superbugs. Increased geographical mobility of these bacteria will only make things worse. (more…)
Plasmid Addiction Systems Are Behind Bacteria’s Toxic Addiction to DNA
For bacteria, addiction to DNA can be a life or death situation. Lose that DNA and the bacterium suffers an unfortunate toxic death.
Many bacteria easily transfer DNA amongst themselves in the forms of plasmid DNA. Plasmids are mobile genetic elements that replicate independently of the chromosome. These small circular pieces of DNA often contain genes that provide its carrier a survival advantage under specific environmental conditions. For example, if a bacterium contains a plasmid with an antibiotic resistance gene, it can survive antibiotic treatment. But, the plasmid is not beneficial to its host cell in all situations and poses a metabolic burden for the host. So why do these plasmids exist and remain in bacteria? (more…)
Eaten alive from the inside: predatory bacteria kill pathogenic bacteria from the inside out
When it comes to predators, we naturally think of large, agile, and powerful animals on the prowl. But we often don’t think about the most abundant predators on our planet, predators of the microscopic world. In the depths of the microbial universe, predatory bacteria (those that feast upon other bacteria) have emerged. These bacteria are now ubiquitous in terrestrial and marine environments. Predatory bacteria penetrate the outer membrane of bacterial prey and ingest their prized nutrients, killing the prey. (more…)
Solving the plasmid paradox: evolutionary advantages of multicopy plasmids
Today marks the end of 2016's World Antibiotic Awareness Week, aimed to increase awareness of antibiotic resistance and to advocate for the prudent use of these drugs.
One of the key drivers of antibiotic resistance is how rapidly bacteria acquire DNA from the environment or from other bacteria. Resistance elements are often carried on mobile elements, DNA that can move around the genome or be transferred to other genomes. The almost universal rapid assimilation of DNA by bacteria leads to the acquisition of multiple antibiotic resistance genes in a variety of bacterial species. One such example of a DNA mobile element is the plasmid, small circular DNA that replicates independently of the chromosome and can be transferred from bacterium to bacterium during cell division, transformation, and conjugation. (more…)