Nav: Home

Are amoebae safe harbors for plague?

January 16, 2018

Amoebae, single-celled organisms common in soil, water and grade-school science classrooms, may play a key role in the survival and spread of deadly plague bacteria.

New Colorado State University research shows that plague bacteria, Yersinia pestis, not only survive, but thrive and replicate once ingested by an amoeba. The discovery could help scientists understand why plague outbreaks can smolder, stay dormant for years, and re-emerge with a vengeance.

The study in Emerging Infectious Diseases was led by David Markman, a Vice President for Research Fellow and Department of Biology graduate student working with Professor Michael Antolin. A former government researcher for malaria vaccines, Markman is investigating whether plague bacteria use amoebae as unwitting hosts to evade detection and multiply.

The research is part of a larger effort led by Mary Jackson, professor in the Department of Microbiology, Immunology and Pathology, to investigate various infectious diseases' interactions with amoebae, including bovine tuberculosis and melioidosis. The studies have been supported by a Vice President for Research initiative called One Health.

Plague, most famous for the Black Death of the 14th century, is alive today and is experiencing a re-emergence particularly in Sub-Saharan Africa, according to the Centers for Disease Control and Prevention. In Colorado, animals including prairie dogs and black-footed ferrets carry fleas that host the bacteria. Outbreaks can wipe out whole prairie dog colonies, and humans or pets can also become infected.

Plague, unlike many other infectious diseases, seems to go dormant after an outbreak and re-emerge via the same strains of bacteria, indicating that the bacteria have lain quiet, rather than mutating. Where they go during this quiet period has eluded scientists. Markman's study provides new support for the theory that amoebae are the answer.

Ubiquitous in soil and water, amoebae may be ideal hosts for plague bacteria when they leach into the ground from, say, a recently deceased prairie dog. To test the theory, Markman and teammates donned protective suits and took soil samples near plague outbreaks in prairie dog colonies. The researchers isolated different species of amoebae and tested whether the bacteria survived ingestion by the various amoebae.

In the lab, the plague bacteria lived for up to 48 hours inside the amoeba, and could possibly survive for longer, Markman said. A species of amoeba called Dictyostelium discoideum seemed to make the best home for plague.

"The bacteria were not just hanging out, but they were surviving and actually quite happy inside the amoebae, and replicating," Markman said. "By contrast, most bacteria get digested by amoebae and are decimated in under an hour."

Markman's hope is to help prevent human cases of plague by being able to identify how the disease persists. He's currently supported by a Department of Defense fellowship, which is aimed at identifying whether such amoeba-resistant plague could be used as bioterrorism agents.

The scientists' next step is to further probe not only how long plague can survive in amoebae, but also whether plague-filled amoebae can develop into a resilient, cystic phase, and re-animate years later.

"If [our lab] can show that the bacteria can stay in the cysts for years, it could explain outbreaks followed by two years of dormancy and re-emergence seemingly out of nowhere," Markman said.
-end-
For his work on amoebae and plague, Markman won the Young Investigator Award at the annual meeting of the American Society of Tropical Medicine and Hygiene (ASTMH) last month in Baltimore, Maryland.

Link to paper: https://wwwnc.cdc.gov/eid/article/24/2/17-1065_article

Colorado State University

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

Warped Reality
False information on the internet makes it harder and harder to know what's true, and the consequences have been devastating. This hour, TED speakers explore ideas around technology and deception. Guests include law professor Danielle Citron, journalist Andrew Marantz, and computer scientist Joy Buolamwini.
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

How to Win Friends and Influence Baboons
Baboon troops. We all know they're hierarchical. There's the big brutish alpha male who rules with a hairy iron fist, and then there's everybody else. Which is what Meg Crofoot thought too, before she used GPS collars to track the movements of a troop of baboons for a whole month. What she and her team learned from this data gave them a whole new understanding of baboon troop dynamics, and, moment to moment, who really has the power.  This episode was reported and produced by Annie McEwen. Support Radiolab by becoming a member today at Radiolab.org/donate.