Copper antimicrobials can drive antibiotic resistance in bacteria, but there’s a fix, scientists say

Copper has become an ally in the battle against bacteria resistant to antibiotics. Copper sulfate liquids, for example, have been used since the 1700s to control fungal infections in vineyards, orchards and many other types of agricultural environments. Copper surfaces are now often used in health care to help keep sterile installations. But too much of a good thing can create the very problem that he tries to solve.

According to new research published in Evolution, medicine and public healthUCLA microbiologists have found that intensive use of copper antimicrobials can also cause antibiotic resistance in bacteria. However, resistance decreases quickly without exposure to copper, which suggests that copper could help reduce antibiotic resistance if they were alternated with other measures.

“Some published research shows that the transition to copper does not necessarily solve the problem of resistance to antibiotics. We wanted to know what would happen to bacteria in environments where the high use of copper, such as copper -based pesticides and agricultural fungicides, would exert evolutionary pressure on bacteria over time,” said the first author of Sada Boyd-Vorsah, who conducted research as a postdoctoral researcher.

“We have found that bacteria that evolve copper resistance also become resistant to antibiotics, perhaps because they use biological routes which help them withstand copper to also resist antibiotics.”

Bacteria strains that cannot be killed by antibiotics represent a serious threat to the ability of medicine to treat infectious diseases. Resistant strains emerge because some individuals in a bacterial population inevitably survive a solid antibiotic course and transmit to the following generations the features which helped them to stay alive. This process, which biologists call natural selection, guarantees that the traits that help individuals to survive and reproduce will become common enough for the population to persist in the face of environmental pressure.

Like antibiotics, everything used to kill microbes, which are organisms such as bacteria, viruses, yeasts and fungi, can create a hostile environment that causes resistance. This may include chemicals, metals, extreme heat and cold.

“In previous research, our laboratory has shown that the path that helps bacteria manage a very old stressor factor, which is an extreme temperature, could be the path with which they treat antibiotics,” said the corresponding author Pamela Yeh, who is a teacher of ecology and evolutionary biology of the UCLA. “Because this path has evolved a long time ago, it is probably common to many types of bacteria.”

Study methodology

The team cultivated colonies of E. Coli in the Petri boxes and exposed them to copper sulfate, which is a common disinfectant and a fungicide. Only 8 of the 50 populations of origin survived, and subsequent generations were cultivated from them and exposed again to copper to develop populations resistant to copper. Then they tested copper -resistant bacteria with a variety of current antibiotics and found that they also resist antibiotics.

Genetic analysis has shown that copper -resistant bacteria had evolved 477 genetic mutations which were not found in the control populations. Some of these mutations were – not surprisingly – on the genes associated with metal resistance, but not with antibiotic resistance. The result supports the previous discovery of Yeh Lab that bacteria use the same ways to cope with several stress factors and indicate that antibiotic resistance can be driven by environmental pressures other than antibiotics alone.

“Even if copper antimicrobians are becoming more and more common, copper-resistant bacteria are not yet common. But it is useful to know that if they become copper resistant, they will probably also be resistant to antibiotics. Copper is always an excellent antimicrobial, but (we) simply have to be aware (our use, because we do not want to end up with a situation Now “who is now a guest assistant professor at the Winston-Salem State University.

To the surprise of researchers, however, bacteria began to lose their resistance after only seven days without exposure to copper. In some populations, the resistance fell but remained high, while in others, it fell to the basic levels, showing that there was a certain genetic variability between the resistant populations.

By alternating the use of copper with other antimicrobials, it should be possible to use them to control the microbes without driving, the researchers said. Although the research was carried out on E. coli, the researchers said that the discovery probably applies to many other types of bacteria.

“I do not see any reason why we would not expect that it is probably a generalizable scheme that could be found in many, perhaps all, species of bacteria because the mechanisms that confer resistance are probably very old evolution,” said Yeh.