Study decrypted transmission of drug resistance in bacteria

Bacteria use gene transfer to pass on resistance
The development of resistant bacterial strains is a major problem worldwide. Medicinal treatments lose their effect and previously well-controlled diseases are becoming a deadly danger. The rapid spread of resistance through the exchange of genetic information between the bacteria is made possible. Scientists at the Institute of Molecular Biosciences at Graz University of Applied Sciences worked together with British researchers to find out exactly how it works.

The exchange of genetic information allows bacteria to pass on resistance. The current results of the research team around Prof. dr. According to Ellen Zechner from the Institute of Molecular Biosciences at the University of Graz, the enzyme relaxase plays a crucial role here. In their study, the scientists deciphered the structure of the enzyme, which influences the exchange of DNA between bacteria. With its help, entire populations of pathogens can be resistant in a very short time to various antibiotics, the experts emphasize. The results of the researchers were published in the renowned journal "Cell".

Bacteria can pass on resistance through the exchange of genetic information. A crucial role is played by the enzyme relaxase. (Image: Dr_Kateryna / fotolia.com)

Structure of the key enzyme determined
"The rapidly growing number of bacterial strains that can no longer be attacked by antibiotics poses major challenges for medicine and research," warn the scientists. An essential role in the development of resistance plays the exchange of genetic information among the pathogens. The fact that bacteria can always exchange genetic information has been known since the 1950s, explain the experts. But so far, the exact process of this process has remained largely unclear. "Despite intensive research, we have only now succeeded in determining the structure of the responsible key enzyme," emphasizes Prof. Zechner.

Within minutes, large quantities of DNA are transferred
According to the scientists, gene transfer between bacteria takes place with the help of the enzyme relaxase, which selectively selects genetic information, cuts through the two DNA strands and transports one of them through a tunnel into the neighboring bacterium. The missing strand will be reproduced in a very short time and both bacteria then show the immunity conferred against certain drugs. The resistant can in turn be passed on by both bacteria. In this way "large amounts of DNA are transferred within minutes", which explains why antibiotic resistance spreads so rapidly, reports Prof. Zechner.

Approach to new drugs
The researchers hope that their findings could contribute in the future, "to develop new drugs that prevent the exchange of genes between bacteria." The previous experiments were, inter alia, failed because "we had no detailed picture of the enzyme," said Prof. Zechner. According to the experts, the current study results provide completely new clues to eliminate the relaxase and thus to curb the spread of antibiotic resistance. (Fp)