WASHINGTON — The word “superbug” may elicit comic book-style images of a bulging green monster that terrorizes fictional cities and keeps children from falling asleep at night.
The real thing is much more terrifying.
A superbug is a strain of bacteria that has become resistant to antibiotic drugs — the Centers for Disease Control and Prevention calls it “one of our most serious health threats.”
That’s because every year, drug-resistant bacteria infect more than 2 million Americans and kill at least 23,000, the CDC reports.
Bacterial infections are commonly treated with antibiotics, but over the past 75 years, more strains of bacteria have developed resistance to the drugs due to the overuse and misuse of antibiotics, the spread of resistant strains of bacteria from person to person, and environmental and food sources.
And while antibiotic-resistant bacteria are everywhere, they’re most dangerous in hospitals and clinics, since patients in a medical setting are already vulnerable to infection due to weakened immune systems.
“Because a lot of these patients are immunocompromised, they tend to get sick more easily,” says Rodney Donlan, a research microbiologist in the division of Healthcare Quality Promotion at the CDC.
But a team of researchers led by Garry Laverty, a lecturer and pharmaceutical scientist at the School of Pharmacy at Queens University in Belfast, Ireland, may have a way to combat infections from resistant bacteria, including Pseudomonas aeruginosa, staphylococci and E.coli. The solution is a gel that prevents these bacteria from becoming resistant to treatment.
“A bacteria will want to attach to a surface, and it can be any surface at all,” says Laverty, who worked on the research for two years in conjunction with Brandeis University’s Department of Chemistry.
“But when a bacteria attaches to a surface, they can form a jelly-like substance, called a biofilm — and this makes the bacteria very resistant to standard antibiotic treatments, because this jelly-like substance actually stops the penetration of the drugs to the bacteria that’s encased within this biofilm.”
In hospitals, bacteria are especially problematic when they attach to medical devices — such as hip implants, catheters, heart valves and pacemakers that are placed in a patient’s body — and then don’t respond to routine antibiotic treatment, Laverty says.
“These devices have been shown to become colonized by different microorganisms, and when the microorganisms colonize in the patient, they tend to form microbial biofilms, and with that comes a lot of issues,” says the CDC’s Donlan, who leads a research group investigating microbial biofilms and their role in healthcare-associated infections.
One of the biggest issues with biofilms is the bacteria’s resistance or tolerance to treatment. This happens due to a number of reasons, Donlan says.
“There’s just something about the biofilm that prevents [the bacteria] from being susceptible to different types of drugs,” he says.
The gel Laverty and his team developed is made of peptides — “molecules that are the building blocks of natural proteins and natural tissues,” he explains. The peptide gel protects the surface of a medical device and “acts like an antimicrobial force field,” preventing the bacteria from attaching and forming its film resistance. At the same time, the gel leaves the body’s healthy cells unharmed, the research says.
“The patient benefits because there’s a lot of suffering involved with these medical-device infections; there’s a lot of money that’s spent to try to tackle these infections. If the infection actually develops, treatment is likely to fail; therefore, something like a hip replacement has to be removed, and that causes more pain for the patient and more days off work,” Laverty says.
The CDC says that in the U.S., antibiotic-resistant infections add considerable and avoidable costs to the healthcare system, often requiring prolonged and costlier treatments and extended hospital stays. Antibiotic resistance is estimated to cause $20 billion a year in excess direct healthcare costs and $35 billion a year for lost societal productivity, the CDC says.
Currently, if an antibiotic resistant bacteria infection occurs in a patient with an implanted medical device, physicians might try a combination of antibiotics (CDC’s Donlan explains sometimes a combination of a few is better than one) or an antimicrobial lock therapy, which uses drugs to try to disperse the biofilm.
Donlan says there’s a lot of laboratory research being done in the area of biofilms and antibiotic resistance, and some studies have been performed on animal models.
“Where we need to go with all of that, of course, is to do clinical studies to validate these kinds of approaches,” he says.
Laverty says he hopes the research will interest and engage the pharmaceutical industry and that it will one day be used in a hospital setting to prevent infections and save lives. His research will be published in the journal Biomacromolecules next month.