Bacteria harbor secret weapons against antibiotics

The ability of pathogenic bacteria to evolve resistance to antibiotic drugs poses a growing threat to human health worldwide.

And scientists have now discovered that some of our microscopic enemies may be even craftier than we suspected, using hidden genetic changes to promote rapid evolution under stress and developing antibiotic resistance in more ways than previously thought. The results appear in a new paper in the journal Biomicrofluidics.

In the paper, researchers from Princeton University in New Jersey describe how they observed two similar strains of E.coli bacteria quickly developing similar levels of antibiotic resistance using surprisingly different genetic mutations. Developing different solutions to the same problem shows the bacteria have a diverse arsenal of genetic "weapons" they can develop to fight antibiotics, potentially making them more versatile and difficult to defeat.

"Bacteria are clever – they have hidden ways to respond to stress that involve re-sculpting their genomes," said Robert Austin, a biophysicist at Princeton who led the research team.

Realizing how effectively bacteria can survive drugs is a sobering thought, Austin said. "It teaches us that antibiotics have to be used much more carefully than they have been up to this point," he said.

The team uses a custom-made microfluidic device that contains approximately 1,000 connected microhabitats in which populations of bacteria grow. The device generates complex gradients of food and antibiotic drugs similar to what might be found in natural bacterial habitats like the gut or other compartments inside a human body.