A new paper in the February 17th edition of the journal Molecular Cell describes how exposure to low levels of antibiotics increases mutations in E. coli and Staphylococcus bacteria hundreds of times more than normal, making the creation of drug-resistant strains more likely.
This finding adds to concerns about antibiotic resistance brought on by poor prescription practices among doctors, patients who don't take all their medicine and even low doses of antibiotics given to animals to help them grow faster.
The researchers found that while low levels of antibiotics may not be enough to kill off the bacteria, they still stress them. That stress causes the bacteria to produce free radicals, says James Collins, a biomedical engineer at Boston University and one of the paper's authors. Basically, if the antibiotic dose isn't high enough to kill every bacterium in sight, "you could be creating a zoo with a wide range of mutations," says Collins.
"Upping the antibiotic dosage may be a viable solution but not the ultimate one," says Bozena Korczak, Vice President Drug Development at Radnor, PA-based PolyMedix Inc. Driven by science conducted at the University of Pennsylvania, PolyMedix is investigating a novel class of antibiotic drugs that imitate natural human immunity and mimic the activity of host defense proteins, creating a lower risk for developing bacterial resistance. Host defense proteins are the oldest and most effective antimicrobial defense system in virtually all living creatures. Even with hundreds of millions of years of evolution, the host defense proteins have not developed widespread bacterial resistance, validating PolyMedix's approach for its new antibiotic drugs.