Nav: Home

A host's genes likely influence the spread of antibiotic resistance

January 29, 2020

  • Bacteria share the genes responsible for antibiotic resistance through circular pieces of DNA called plasmids, but the process of their transfer in the host is complex.

  • New findings in mSphere suggest that the genetic makeup of the host organism can influence the transfer of plasmids.

  • By identifying the host factors that facilitate or stop plasmid transfer, the researchers hope to identify new ways to stop the spread of antibiotic resistance, which kills tens of thousands of people every year in the United States alone.
Washington, DC - January 29, 2020 - In the gastrointestinal tract of host animals, bacteria can exchange the genes responsible for antibiotic resistance (AR) via small, circular chunks of DNA called plasmids. However, the process in this complex environment isn't completely understood, and AR has become a public health menace. Every year, according to the CDC, more than 2.8 million people are diagnosed with infections resistant to antibiotic treatment, and 35,000 people die.

"The human gut has millions of bacteria," said microbiologist Melha Mellata, Ph.D., at Iowa State University in Ames, Iowa. "If an AR plasmid is introduced into our gut through contaminated food or by another means, it will quickly spread to other gut bacteria, which will generate bacteria resistant to treatments with antibiotics." To stop that from happening, she said, researchers need to know what factors trigger or reduce the transfer of plasmids.

This week in mSphere, an open-access journal of the American Society for Microbiology, Mellata and her colleagues published findings that suggest the genetic background of the host organism itself may play an underappreciated role in the sharing of resistance between bacteria, at least in mice. The researchers analyzed how AR-associated plasmids were transferred from one microbe to another in two genetically different groups of mice. Both groups started with the same population of gut microbes and were fed the same diet in the same environment.

The researchers found that the plasmids transferred successfully in some mice but not in others, which meant that AR didn't spread in the same way in all groups. That observation led the researchers to run further analyses, which suggested that the microbial transactions could be attributed to genetic factors in the mice themselves, as well as the complexity of the gut microbiota.

"There is something in the host's genes that can amplify this transfer," said Mellata, who led the study.

Mellata and her colleagues used a strain of Salmonella known to harbor large plasmids that make the bacterium resistant to treatment with streptomycin and tetracycline, two common antibiotics. Previous studies by other researchers have confirmed that these plasmids can transfer to Escherichia coli.

But those previous experiments were conducted in bacterial cultures. For the new study, Mellata's group studied how the plasmids spread to E. coli in the animals themselves. A better understanding of how resistance spreads requires examining what's going on in the host gastrointestinal tract, she said. "We need to study this issue through the lens of the host's complex environment, since in reality this is how this phenomenon happens."

Mellata's research at Iowa State focuses on understanding large plasmids--which may contain many AR-related genes--and developing vaccines for strains of E. coli that are resistant to antibiotic treatment. Previous work by her group showed that mouse strains with a limited set of known gut microbes are more susceptible to infections than conventional mice. That observation led them to investigate how the genetic background of the animal itself--and not just the microbial community--might have some influence on the transfer of plasmids.

Mellata's group is now following up on the experiment by trying to identify the specific genetic host factors that can trigger the plasmid transfer. She hopes those findings can lead to a new way to stop the spread of antibiotic resistance. "If we can target those specific host factors, we can reduce the plasmid transfer, which will prevent the emergence of new antibiotic-resistant strains," she said.

"People are dying from bacterial infections," she said. "They should not be dying from bacteria like E. coli. The emergence of bacteria resistant to last-resort antibiotics is happening really fast, and we want to discover what's making that happen."
-end-
The American Society for Microbiology is the largest single life science society, composed of more than 30,000 scientists and health professionals. ASM's mission is to promote and advance the microbial sciences.

ASM advances the microbial sciences through conferences, publications, certifications and educational opportunities. It enhances laboratory capacity around the globe through training and resources. It provides a network for scientists in academia, industry and clinical settings. Additionally, ASM promotes a deeper understanding of the microbial sciences to diverse audiences.

American Society for Microbiology

Related Bacteria Articles:

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.
More Bacteria News and Bacteria Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: The Power Of Spaces
How do spaces shape the human experience? In what ways do our rooms, homes, and buildings give us meaning and purpose? This hour, TED speakers explore the power of the spaces we make and inhabit. Guests include architect Michael Murphy, musician David Byrne, artist Es Devlin, and architect Siamak Hariri.
Now Playing: Science for the People

#576 Science Communication in Creative Places
When you think of science communication, you might think of TED talks or museum talks or video talks, or... people giving lectures. It's a lot of people talking. But there's more to sci comm than that. This week host Bethany Brookshire talks to three people who have looked at science communication in places you might not expect it. We'll speak with Mauna Dasari, a graduate student at Notre Dame, about making mammals into a March Madness match. We'll talk with Sarah Garner, director of the Pathologists Assistant Program at Tulane University School of Medicine, who takes pathology instruction out of...
Now Playing: Radiolab

What If?
There's plenty of speculation about what Donald Trump might do in the wake of the election. Would he dispute the results if he loses? Would he simply refuse to leave office, or even try to use the military to maintain control? Last summer, Rosa Brooks got together a team of experts and political operatives from both sides of the aisle to ask a slightly different question. Rather than arguing about whether he'd do those things, they dug into what exactly would happen if he did. Part war game part choose your own adventure, Rosa's Transition Integrity Project doesn't give us any predictions, and it isn't a referendum on Trump. Instead, it's a deeply illuminating stress test on our laws, our institutions, and on the commitment to democracy written into the constitution. This episode was reported by Bethel Habte, with help from Tracie Hunte, and produced by Bethel Habte. Jeremy Bloom provided original music. Support Radiolab by becoming a member today at Radiolab.org/donate.     You can read The Transition Integrity Project's report here.