Antibiotic resistance has many people scared, and with good reason. We've forgotten what it's like to live in a world where most bacterial infections can't be cured easily, and where even simple surgery is very dangerous. Most work on the topic, understandably, involves finding new antibiotics bacteria have not yet evolved resistance to, but one team is offering a very different solution. They have found that applying a weak electric field to bandages prevents biofilms forming, and reduces the risk of infection.
Bacteria turn wounds septic, interfering with recovery and often proving fatal. Biofilms are congregations of microorganisms on surfaces that protect their component bacteria against antibiotics and the immune system. When microbiologists realized biofilms use electrostatic interactions to grip onto surfaces, they wondered if it might be possible to disrupt this process using weak electric fields.
This possibility was first demonstrated in 1992, but it has taken 25 years to move from proving the principle on glass to creating and testing a bandage to treat real wounds. Dr Chandan Sen, of Ohio State University, realized that having bandages connected to a power supply, or even a battery, would create a lot of practical difficulties. Therefore, he searched for a way to create small amounts of electricity in situ.
In Annals of Surgery, Sen and colleagues announced the success of what he calls a “wireless electroceutical dressing” (WED) printed with silver and zinc particles. When wet, WED produces a small electric field. It was applied to pigs and worked much better than a placebo both on fresh wounds (two hours after injury) and seven days after infection when a biofilm had had a chance to become established. In both cases, wounds were more likely to close with WED than a conventional bandage – counts of bacteria were lower, and molecules known to interfere with healing were reduced.
"Since it relies on electrical principles, it's not subject to the mechanisms that may promote drug resistance,” Sen said in a statement. Trials on human burns victims start soon.
As useful as WED might be for external infections, it's little help if bacteria take hold of your lungs or bloodstream. These are the more frightening faces of antibiotic resistance, but there's good news on that front too, although it's much further from being applied than Sen's work.
Teixobactin is a natural antibiotic that binds to bacteria using enduracididine, a rare amino acid. Unfortunately, enduracididine isn't easy to synthesize, which has held back teixobactin's application. However, Dr Ishwar Singh of the University of Lincoln and colleagues have revealed in Chemical Science that it's possible to replace enduracididine with two alternative amino acids, without losing potency, making it easier to synthesize teixobactin in quantities suitable for widespread use.