University of Wyoming Extension News

UW research one step toward solving antibiotic resistance

Associate Professor Dan Wall

Associate Professor Dan Wall

Pursued by death squads. Assassins at every turn.

It ain’t easy being Myxococcus xanthus – or worse – another bacterium in their path.

Luckily for humans, the soil bacteria hooligans (depending upon which side of the single cell microorganisms you’re on) and scientists at the University of Wyoming could be building steps toward solving antibiotic resistance.

The death rate for patients with serious infections treated in hospitals is about twice that in patients with infections caused by non-resistant bacteria, according to the World Health Organization. Many infectious diseases risk becoming untreatable and uncontrollable.

Antibiotic resistance extends far beyond being unable to control illnesses like pneumonia. Ineffective antibiotics could compromise organ transplants, cancer chemotherapy and major surgery.

Resistance begins with the bacteria version of a very intimate hello and handshake then a complex process of exchanging immunity.

Molecular biologist Dan Wall in the College of Agriculture and Natural Resources and his research group found that myxobacteria recognize related strains and can join outer membranes and exchange cellular material. His research was published in the November PLOSGenetics journal.

           Through that research, Wall, an associate professor in the Department of Molecular Biology, found that membrane fusion can also provide protection from bacteria hit men.

Myxococcus xanthus are unusual in the bacteria world – they are social, said Wall. They interact and form units of cells that exhibit group movement.

“They live in soil, which is a cosmopolitan environment made up of thousands of differentkinds of microbe species, and myxobacteria have the ability to recognize each other and can aggregate in response to starvation and build spectacular fruiting structures that can be seen with the naked eye,” said Wall.

However, different strains or isolates of the same bacteria species do not play nice in the sandbox.

“Frequently, one can find that one strain will kill another strain of the same species,” said Wall, who joined the department in 2007.

These components are typically called bacteriocins – specific peptides or proteins that recognize another closely related bacterium and kills it unless it encodes an immunity protein, said Wall. The cell that produces the bacteriocin also has to make an immunity factor to protect itself from the toxin. Any related neighboring cell that doesn’t have the immunity factor is targeted and killed – a much more violent end than those who lose immunity on that television show “Survivor.”

Wall’s lab determined that a gene necessary for the transfer of outer membrane material acts as a cell surface receptor – the molecular mechanism for recognition between cells.

Wall swapped the ‘receptor’ between two strains that did not belong to the same recognition group, allowing them to exchange outer membrane components, and in these cases,  it provided protection from killing.

“We’ve interpreted this result to mean there is an immunity factor(s) that can be transferred between cells,” he said.

By extension, the exchange process could also play a role in antibiotic resistance, he said.

Wall’s research is also down-to-earth. His discoveries can apply to processes in the bacteria’s home turf.

“Our lab species of myxobacteria are commonly found in soil,” said Wall. “They prey on other bacterial and fungal organisms, including crop pathogens.”

In another study, they found myxobacteria produce different types of broad-spectrum antibiotics, which serve as weapons to neutralize and kill prey bacteria for enzymatic digestion as food.

“And, importantly, myxobacteria do not harm crops, so in a separate project we are exploring the utility of myxobacteria as a biological control agent to protect crops,” said Wall.