Nav: Home

Antibiotic resistance persists in bacteria, even absent selection pressure from antibiotics

August 01, 2016

Washington, DC - August 1, 2016 - Plasmids are pieces of independent DNA that often carry multiple antibiotic resistance genes. Plasmids can jump from one bacterium to another, spreading that resistance. A team of French investigators now shows that bacteria that acquire plasmids containing resistance genes rarely lose them. The research is published in Antimicrobial Agents and Chemotherapy, a journal of the American Society for Microbiology.

In the study, the investigators focused on plasmids carrying resistance to extended spectrum cephalosporins. "Cephalosporins are antimicrobials that are critical to human health, as they are used to treat urinary tract, and other infections," said corresponding author Isabelle Kempf, D.V.M., head of the Mycoplasmology-Bacteriology Unit, the Agence Nationale de Securité Sanitaire, Université de Bretagne Loire, Ploufragan, France. The gene for resistance to extended spectrum cephalosporins is frequently carried on plasmids, often along with multiple genes for resistance to other antimicrobials.

The investigators inoculated pigs with an extended spectrum cephalosporin-resistant, non-pathogenic strain of Escherichia coli, and placed the pigs in pens with non-inoculated pigs. A plasmid in the E. coli carried the gene for extended spectrum cephalosporin resistance, as well as four other resistance genes. The investigators collected fecal samples from the pigs, at different time points following inoculation. From these, they grew 353 isolates of E. coli.

During the experiment, the pigs did not receive extended spectrum cephalosporin antibiotics. That meant that there was no selection pressure that might have favored the persistence of extended spectrum cephalosporin resistance in the bacterial populations. Nonetheless, all but three of the 353 isolates carried the resistance gene.

"Our results show that once a plasmid encoding resistance genes is transferred to a bacterial host, the probability that the bacteria will lose the encoded resistances is quite low, even absent a selective pressure," said Kempf

"Plasmids have developed sophisticated mechanisms to ensure their transmission to daughter cells during cell division," Kempf explained. "A better knowledge of these mechanisms and development of innovative tools to counteract them could result in new strategies to combat antimicrobial resistance."
-end-
The American Society for Microbiology is the largest single life science society, composed of over 47,000 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:

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?
Detecting bacteria in space
A new genomic approach provides a glimpse into the diverse bacterial ecosystem on the International Space Station.
Hopping bacteria
Scientists have long known that key models of bacterial movement in real-world conditions are flawed.
Bacteria uses viral weapon against other bacteria
Bacterial cells use both a virus -- traditionally thought to be an enemy -- and a prehistoric viral protein to kill other bacteria that competes with it for food according to an international team of researchers who believe this has potential implications for future infectious disease treatment.
Drug diversity in bacteria
Bacteria produce a cocktail of various bioactive natural products in order to survive in hostile environments with competing (micro)organisms.
Bacteria walk (a bit) like we do
EPFL biophysicists have been able to directly study the way bacteria move on surfaces, revealing a molecular machinery reminiscent of motor reflexes.
Using bacteria to create a water filter that kills bacteria
Engineers have created a bacteria-filtering membrane using graphene oxide and bacterial nanocellulose.
Probiotics are not always 'good bacteria'
Researchers from the Cockrell School of Engineering were able to shed light on a part of the human body - the digestive system -- where many questions remain unanswered.
More Bacteria News and Bacteria Current Events

Top Science Podcasts

We have hand picked the top science podcasts of 2019.
Now Playing: TED Radio Hour

Risk
Why do we revere risk-takers, even when their actions terrify us? Why are some better at taking risks than others? This hour, TED speakers explore the alluring, dangerous, and calculated sides of risk. Guests include professional rock climber Alex Honnold, economist Mariana Mazzucato, psychology researcher Kashfia Rahman, structural engineer and bridge designer Ian Firth, and risk intelligence expert Dylan Evans.
Now Playing: Science for the People

#540 Specialize? Or Generalize?
Ever been called a "jack of all trades, master of none"? The world loves to elevate specialists, people who drill deep into a single topic. Those people are great. But there's a place for generalists too, argues David Epstein. Jacks of all trades are often more successful than specialists. And he's got science to back it up. We talk with Epstein about his latest book, "Range: Why Generalists Triumph in a Specialized World".
Now Playing: Radiolab

Dolly Parton's America: Neon Moss
Today on Radiolab, we're bringing you the fourth episode of Jad's special series, Dolly Parton's America. In this episode, Jad goes back up the mountain to visit Dolly's actual Tennessee mountain home, where she tells stories about her first trips out of the holler. Back on the mountaintop, standing under the rain by the Little Pigeon River, the trip triggers memories of Jad's first visit to his father's childhood home, and opens the gateway to dizzying stories of music and migration. Support Radiolab today at Radiolab.org/donate.