My watch list
my.bionity.com  
Login  

Bacteria acquire resistance from competitors

02-Jan-2018

Biozentrum of the University of Basel

Bacteria not only develop resistance to antibiotics, they also can pick it up from their rivals. In a recent publication in "Cell Reports", Researchers from the Biozentrum of the University of Basel have demonstrated that some bacteria inject a toxic cocktail into their competitors causing cell lysis and death. Then, by integrating the released genetic material, which may also carry drug resistance genes, the predator cell can acquire antibiotic resistance.

The frequent and sometimes careless use of antibiotics leads to an increasingly rapid spread of resistance. Hospitals are a particular hot spot for this. Patients not only introduce a wide variety of pathogens, which may already be resistant but also, due to the use of antibiotics to combat infections, hospitals may be a place where anti-microbial resistance can develop and be transferred from pathogen to pathogen. One of these typical hospital germs is the bacterium Acinetobacter baumannii. It is also known as the "Iraq bug" because multidrug-resistant bacteria of this species caused severe wound infections in American soldiers during the Iraq war.

Multidrug-resistant bacteria due to gene exchange

The emergence and spread of multidrug resistance could be attributed, among other things, to the special skills of certain bacteria: Firstly, they combat their competitors by injecting them with a cocktail of toxic proteins, so-called effectors, using the type VI secretion system (T6SS), a poison syringe. And secondly, they are able to uptake and reuse the released genetic material. In the model organism Acinetobacter baylyi, a close relative of the Iraq bug, Prof. Marek Basler's team at the Biozentrum of the University of Basel, has now identified five differently acting effectors. "Some of these toxic proteins kill the bacterial competition very effectively, but do not destroy the cells," explains Basler. "Others severely damage the cell envelope, which leads to lysis of the attacked bacterium and hence the release of its genetic material." 

The predator bacteria take up the released DNA fragments. If these fragments carry certain drug resistance genes, the specific resistance can be conferred upon the new owner. As a result, the antibiotic is no longer effective and the bacterium can reproduce largely undisturbed.

Pathogens with such abilities are a major problem in hospitals, as through contact with other resistant bacteria they may accumulate resistance to many antibiotics - the bacteria become multidrug-resistant. In the worst case, antibiotic treatments are no longer effective, thus nosocomial infections with multidrug-resistant pathogens become a deadly threat to patients. 

Toxic proteins and antitoxins

"The T6SS, as well as a set of different effectors, can also be found in other pathogens such as those which cause pneumonia or cholera," says Basler. Interestingly, not all effectors are sufficient to kill the target cell, as many bacteria have developed or acquired antitoxins - so-called immunity proteins. "We have also been able to identify the corresponding immunity proteins of the five toxic effectors in the predator cells. For the bacteria it makes absolute sense to produce not only a single toxin, but a cocktail of various toxins with different effects," says Basler. “This increases the likelihood that the rivals can be successfully eliminated and in some cases also lysed to release their DNA.”

Conquest of new environmental niches

Antibiotics and anti-microbial resistance have existed for a long time. They developed through the coexistence of microorganisms and enabled bacteria to defend themselves against enemies or to eliminate competitors. This is one of the ways in which bacteria can conquer and colonize new environmental niches. With the use of antibiotics in medicine, however, the natural ability to develop resistance has become a problem. This faces researchers with the challenge of continually developing new antibiotics and slowing down the spread of drug resistance.

Facts, background information, dossiers
More about Universität Basel
  • News

    How does Parkinson's disease develop?

    Parkinson's disease was first described by a British doctor more than 200 years ago. The exact causes of this neurodegenerative disease are still unknown. In a study recently published in eLife, a team of researchers led by Prof. Henning Stahlberg from the Biozentrum of the University of Ba ... more

    How to track and trace a protein: Nanosensors monitor intracellular deliveries

    Researchers at the University of Basel’s Biozentrum have developed a method for tracing the movement of proteins within the cell. They tagged proteins with tiny nanosensors, so-called nanobodies, which enable the scientists to live track and trace the proteins' pathway through the cell. The ... more

    Enigma of fatty acid metabolism solved

    Fats are essential for our body. The core components of all fats are fatty acids. Their production is initiated by the enzyme ACC. Researchers at the University of Basel’s Biozentrum have now demonstrated how ACC assembles into distinct filaments. As the researchers report in “Nature,” the ... more

  • Videos

    Virtual Reality in Medicine: New Opportunities for Diagnostics and Surgical Planning

    Before an operation, surgeons have to obtain the most precise image possible of the anatomical structures of the part of the body undergoing surgery. University of Basel researchers have now developed a technology that uses computed tomography data to generate a three-dimensional image in r ... more

    Nuclear Pores Captured on Film

    Zooming into a nuclear pore complex using a high-speed atomic force microscope reveals the selectivity barrier that filters the traffic of molecules passing between the cytoplasm and nucleus in eukaryotic cells. This is comprised of intrinsically disordered proteins known as FG Nucleoporins ... more

  • Universities

    Universität Basel

    Tradition - The city of Basel is home to the oldest university in Switzerland. Founded upon the initiative of local citizens in 1460, the University of Basel is a modern and attractive centre of teaching, learning, and research situated in the heart of the historic old town. Self - managed ... more

Your browser is not current. Microsoft Internet Explorer 6.0 does not support some functions on Chemie.DE