Our problems with the antibiotic-resistant bacteria aren’t new. According to a new study published in the journal Cell, the first antibiotic-resistant “superbugs” emerged about 450 million years ago, even before dinosaurs appeared on the planet. Enterococci bacteria or the superbugs that infect patients and are resistant to drugs have been honing their defensive capabilities for more than 450 million years.
Antibiotic-resistant bacteria infect 70,000 Americans a year
These superbugs are one of the biggest public health concerns. They are spreading rapidly in hospitals. According to the World Health Organization, they infect millions of people every year. Data from the Center for Disease Control and Prevention (CDC) shows that the antibiotic-resistant bacteria infect 70,000 and kill more than 1,000 Americans every year.
Micro-organisms have been adapting to the life in and on animals since the origin of the first multi-cellular organisms about 3.5 billion years ago. Many of them formed a symbiotic relationship with animals, living inside their intestines. But other microbes evolved to become harmful to animals, causing diseases. Genetic analysis revealed that the relatives of modern enterococci have been present in the intestines of animals since the first animal crawled out of the sea onto the land.
Traits developed over millions of years help them survive antibiotics
The earliest enterococci were also capable of surviving extreme conditions such as drought as well as antibiotics and disinfectants. Most bacteria die within minutes after being excreted in the form of feces. But the enterococci can survive both on dry land and in the ocean. Now 450 million years later, their descendants are able to withstand antibiotics and disinfectants that try to destroy their cell walls.
Michael Gilmore, a microbiologist at Harvard University and co-author of the study, said the traits enterococci developed over hundreds of millions of years to survive on land make them so rugged and give them the ability to survive in hospitals. Gilmore and his colleagues wanted to study the evolutionary history of the antibiotic-resistant bacteria, which could help develop better tools to fight them in the modern era.
The superbugs are not only resistant to various types of antibiotics, but they can also pass on the genetic material to other bacteria, helping them develop drug resistance. Researchers analyzed the genomes and behaviors of today’s enterococci as well as fossils records to piece together a picture of how these superbugs evolved into what they are today. Scientists also studied the environmental distribution and biochemical differences.
Identifying targets for the next-gen antibiotics
Ashlee M. Earl of Broad Institute and lead author of the study said understanding how the environment leads the microbes to develop new properties could help researchers predict how the superbugs would adapt to the use of disinfectants, antibiotics, and other products intended to kill germs. Scientists sequenced the DNA of 24 members of the enterococci family.
Gilmore, Earl and their colleagues were able to identify 45 different properties that make microbes resistant to disinfectants and antibiotics in hospitals. Scientists are studying the genes to identify targets for the next generation of antibiotics and disinfectants.
Gilmore said in a press release that the enterococci and thousands of other bacteria live harmlessly in the intestines of almost all animals. In hospitals, patients are given antibiotics to prevent infections. The antibiotics also kill many helpful microbes that keep enterococci under control. In the absence of the microbes that help our body, the superbugs that aren’t killed off develop resistance to the drugs.