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Self-Sterilizing Plastics Kill Drug-Resistant Bacteria

A biotech company is developing polymers and medicines that attack microorganisms



Courtesy of iStockphoto; Copyright: Konstantin Inozemtsev

Despite the proliferation of antibiotics and assorted antibacterial hand lotions and wipes, bacteria remain a moving target for hospitals and clinics seeking to protect their patients from infections. One approach gaining traction in the effort to banish bacteria is to mimic the way the human body attacks these microorganisms by punching holes in bacterial cell membranes and hobbling their ability to morph into antibiotic-resistant pathogens.

Bacteria are becoming increasingly resistant to antibiotics due to a combination of their overuse (which allows bacterial cells to become familiar with these drugs and purge them before they can do their work) and the pathogens' ability to quickly adapt to new conditions. Bacteria divides every 20 minutes, speeding evolution and creating the equivalent of a changing keyhole for makers of antibiotics, says Nicholas Landekic, CEO and founder of PolyMedix, Inc., a Radnor, Pa., biotech firm. "Seventy percent of bacterial infections are resistant," he says, "which is a big problem."

Indeed, bacterial infections are now the fourth leading cause of death in the U.S., killing about 100,000 people each year, according to the U.S. Centers for Disease Control. Ironically, one of the best places to get an infection is the hospital—more than two million cases of hospital-acquired infections are reported in the U.S. annually, according to a paper published recently in The Society of Chemical Industry's journal, Polymer International.

PolyMedix is, with the help of scientists at the University of Pennsylvania, developing drugs and polymers that behave much like the body's own defenses. Among those in the works: medications that can kill bacteria without the need to actually enter the cells themselves as well as new polymers that the company hopes will be used in paints, plastics and textiles to create self-sterilizing products and surfaces. The polymer is not a coating like silver, ammonium salts or phenols, which Landekic says dissolve over time and lose their effectiveness. "Our compounds become part of the surface," he says, and can kill bacteria in a matter of seconds. "If you make the antibiotic part of the material, the effect is long lasting."

The company has no time frame for delivering the antibacterial polymer to store shelves because it is focusing its resources primarily on getting its antibiotic drug to market. The company would need approval from the U.S. Environmental Protection Agency—a process that takes up to 16 months once an application is filed—to include its antibacterial polymer in bedding, carpeting, countertops and towels.

"We've developed a lot of different prototype materials and proven [the polymer] works when added to different materials"—as long as the surface is clean, Landekic says. "The polymers are self-sterilizing, not self-cleaning," he adds. "You have to allow them to interact with the bacteria."

He says the antimicrobial polymers may also be successful in wiping out Stachybotrys chartarum, or "black mold," in residential and commercial buildings, a fungus that can cause lung disease and exacerbate allergies. The polymers also may prove significant in the war on terrorism, which explains why the U.S. Department of Defense handed the company more than $1.6 million to develop drug compounds and polymers able to combat biowarfare pathogens that cause infectious diseases such as anthrax, plague and tularemia. The company received another $3 million for research and development from the U.S. Department of Health and Human Services.

PolyMedix needs the approval of the Food and Drug Administration before it can test meds in development that may one day supplant antibiotics. This new crop of microorganism fighter would, much like the polymers, kill bacteria by punching their membranes full of holes. PolyMedix recently announced that the Health Canada—the country's national health care watchdog—has given the company the green light to begin a human clinical trial to assess the safety and effectiveness of a synthetic compound dubbed PMX-30063, designed to treat systemic infections while avoiding the pitfalls of normal antibiotics no longer effective against bacteria.

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