A new lead for disarming antibiotic-resistant bacteria

November 02, 2020

A virus can stop bacteria from sharing genes for antibiotic resistance among themselves, Texas A&M AgriLife researchers have discovered. The results hint at new ways to treat infections and describe a new feature of a highly diverse, largely unexplored part of the biosphere.

The study, published recently in Proceedings of the National Academy of Sciences, was led by Lanying Zeng, Ph.D., associate professor in the Texas A&M College of Agriculture and Life Sciences Department of Biochemistry and Biophysics.

How some phages infect bacteria

Viruses that only infect bacteria are called bacteriophages, or phages for short. Phages are the most numerous biological entities on Earth. Soil is rife with phages, as is the human gut, and phages that infect and destroy bacteria have found promising uses in combating antibiotic-resistant bacterial infections.

Some phages only infect bacteria whose surface contains cylindrical structures called pili. Named after the Latin word pilus, for spear, pili allow bacteria to transfer genes for advantageous traits, such as drug resistance, and enhance bacteria's ability to move and to attack host cells. Because of pili's link to bacterial virulence, researchers have wondered whether new medications could be created to inactivate this feature. While the ways bacteria benefit from pili are clear, how phages use pili to infect bacteria has remained elusive.

Phage competition

Zeng's team used fluorescence microscopy to delve into how a phage, MS2, enters an E. coli cell. The researchers created MS2 phages that fluoresce and are fully infectious and stable. The phages attach to pili on E. coli cells, making the pili visible through a fluorescence microscope.

Through a series of experiments, Zeng, her graduate student Laith Harb, and the other coauthors obtained a detailed description of what happens when an MS2 phage infects an E. coli.

The team discovered that after a phage attaches to a pilus, the pilus retracts, bringing the phage to the bacterial cell surface. The pilus then breaks off behind the phage. Whereas healthy E. coli replenish broken pili, cells infected by MS2 do not. In this way, other phages are prevented from infecting the same cell. The first phage to reach the cell gains a competitive advantage.

"It's like, 'OK, this cell is mine.' Phages set up their own territory," said Zeng, who is a core faculty member of the Center for Phage Technology, a part of Texas A&M AgriLife Research.

Because the phenomenon gives such a boost to the infecting phage, this occurrence may be widespread among other phage strains that employ pili to infect bacteria, Zeng added.

New ideas for medicine

The results may be of use in medicine, Zeng said. First, using phages to decrease bacterial virulence may give the immune system time to fight off an infection. Second, the results point to a way of dealing with infections that may be gentler for patients than antibiotics or than using phage therapy to destroy bacteria.

"One advantage of our method versus traditional phage therapy is that you do not kill the cell, you just disarm it," Zeng said. "Killing the cell may cause a problem, because inside the cell you may have a toxin that could be released into the host."

Phages that target pili could also reinforce the action of antibiotics. Some bacterial infections only respond to high doses of antibiotics, which can cause side effects. Adding phages to the mix may allow doctors to decrease the needed antibiotic dosage.
-end-


Texas A&M AgriLife Communications

Related Bacteria Articles from Brightsurf:

Siblings can also differ from one another in bacteria
A research team from the University of Tübingen and the German Center for Infection Research (DZIF) is investigating how pathogens influence the immune response of their host with genetic variation.

How bacteria fertilize soya
Soya and clover have their very own fertiliser factories in their roots, where bacteria manufacture ammonium, which is crucial for plant growth.

Bacteria might help other bacteria to tolerate antibiotics better
A new paper by the Dynamical Systems Biology lab at UPF shows that the response by bacteria to antibiotics may depend on other species of bacteria they live with, in such a way that some bacteria may make others more tolerant to antibiotics.

Two-faced bacteria
The gut microbiome, which is a collection of numerous beneficial bacteria species, is key to our overall well-being and good health.

Microcensus in bacteria
Bacillus subtilis can determine proportions of different groups within a mixed population.

Right beneath the skin we all have the same bacteria
In the dermis skin layer, the same bacteria are found across age and gender.

Bacteria must be 'stressed out' to divide
Bacterial cell division is controlled by both enzymatic activity and mechanical forces, which work together to control its timing and location, a new study from EPFL finds.

How bees live with bacteria
More than 90 percent of all bee species are not organized in colonies, but fight their way through life alone.

The bacteria building your baby
Australian researchers have laid to rest a longstanding controversy: is the womb sterile?

Hopping bacteria
Scientists have long known that key models of bacterial movement in real-world conditions are flawed.

Read More: Bacteria News and Bacteria Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.