The threat of antibiotic resistance is nothing to scoff at: The World Health Organization predicts (pdf) that some diseases, including malaria, tuberculosis, and pneumonia, could have “no effective therapies within the next 10 years.” Indeed, 70 percent of hospital-acquired bacterial infections in the United States—which kill 90,000 Americans a year—are resistant to at least one drug, according to the Centers for Disease Control and Prevention. But scientists are working hard to find more potent antibiotics, and they are uncovering them in the strangest of places, from alligators’ veins to cholesterol drugs.
1 Gator Blood Alligators fight off infections far better than humans do, perhaps due to an adaptation that promotes rapid wound healing. Recent lab tests show that tiny amounts of alligator blood extract—some scientists call it alligacin—kill many microbes, including Methicillin-resistant Staphylococcus aureus (MRSA), and help fight HIV.
2 Frog Skin Last year Italian scientists isolated short proteins called antimicrobial peptides from frog skin and tested them on strains of multidrug-resistant bacteria. The peptides not only killed bacteria directly, but also ramped up the host immune system to help clear infections more quickly.
The peptides are so fragile that they rapidly break down in blood; the researchers nevertheless found one that killed five bacterial species in the presence of blood. Among the affected microorganisms were three that commonly cause deadly hospital-acquired infections, including Staphylococcus aureus and two emerging bacterial pathogens, Stenotrophomonas maltophilia and Acinetobacter baumannii, that are a growing cause of infections in hospital intensive-care units.
3 Synthetic Molecules Researchers at Northwestern University recently engineered versions of antimicrobial peptides to make them more resilient. Called peptoids, these synthetic molecules are stronger than natural peptides, last longer in the body, and are cheaper to produce. When the scientists added them to cultures of six bacteria known to cause food poisoning, pneumonia, hospital-acquired infections, and ear and heart infections, the peptoids wiped them all out.
4 Focused phages If bacteria evolve to become drug resistant, why not subject them to bacteria-fighting microbes, called phages, that evolve along with them? When ingested or topically applied, phages cure infections but leave the rest of the body and “good” bacteria alone. So-called phage therapy is widely used in Eastern Europe and is currently undergoing one U.S. clinical trial. Since phages have evolved with their bacterial targets for billions of years, they could solve the problem of antibiotic resistance for good; the downside is that each bacterial strain requires its own tailored phage cocktail, so it could be many years before doctors have a suitably broad range of phages at their disposal.
5 Cholesterol Drugs MRSA bacteria produce an antioxidant that helps destroy toxic free radicals generated in the infection-fighting process. The antioxidant, scientists found, is produced through a process similar to one used by humans to manufacture cholesterol. Thus, researchers wonder whether cholesterol-lowering compounds might act as a new sort of antibiotic. Mice given the drug and then infected with MRSA had 98 percent less bacteria than mice not given the drug.