The rise of antibiotic-resistant bacteria is one of the most serious challenges that medicine faces today. Most strategies to combat these superbugs are focused on efforts to develop ever more powerful antibiotics. But a growing number of researchers such as Scott Hultgren and his team at Washington University School of Medicine in St. Louis are taking a very different tack.

Bacteria that cause many urinary tract infections (UTIs) are normally coated in fine hairlike structures known as pili, which both enable the invasion of host cells and help the bacteria to mount a defense against the host’s immune system. Instead of trying to wipe out these bacteria, Hultgren’s team is trying to create drugs that essentially defang the bacteria by preventing them from growing their pili. "We're leaving the bacteria bald but healthy and happy," says Jerome Pinkner, lab manager for Hultgren. "Rather than trying to kill them, we're working to make them non-pathogenic, so that they will be unable to adhere to or invade the bladder tissues and are readily eliminated from the body." The researchers are hoping to begin tests of their most potent pilicides in animal models in about a year.

What it means: According to an April 2006 National Institute of Allergy and Infectious Diseases fact sheet, resistance to at least one antibiotic has been detected in more than 70% of the bacteria that cause hospital-acquired infections. UTIs mainly occur in women and are one of the most common infections, causing around $1.6 billion in medical expenses every year in the United States. Scientists believe 90% of all UTIs, which have been linked to poor hygiene, sexual behavior, and migration of intestinal flora, are caused by the bacterium e. coli.

Scientists hope that the pilicide approach will significantly diminish the bacteria's ability to find ways of evading the new treatments. Pinkner and his colleagues think the bacteria will find it harder to evolve resistance to a treatment that does not directly threaten their survival. "For bacteria to develop resistance to a new antibiotic, which by definition kills bacteria, all you need is for one bacterium among trillions to acquire a genetic mutation that allows it to survive," Pinkner explains. "We think that pilicides will greatly reduce the pressure to develop resistance and have already shown in the lab that they have no effect on E. coli's growth or metabolic state."

From the Archive:

Jun. 26, 2006: Surviving the New Killer Bug
Mar. 17, 2006: Will We Run Out of Antibiotics?