Maggots eat up resistant bacteria
Creepy crawlies are the latest weapon in the anti-MRSA arsenal.
The drug-resistant bug MRSA has a new adversary — the maggot. Researchers in Manchester, UK, have just won a grant to compare maggots with other more hi-tech treatments for people with diabetes who suffer from infected feet.
A quarter of all people with diabetes are at risk of foot ulcers, because of the reduced blood circulation caused by the damaging effects of high blood glucose. These lesions often become infected. Antibiotic-resistant bacateria such as methicillin-resistant Staphylococcus aureus (MRSA) are becoming increasingly common — and consequently increasingly hard to treat. "MRSA is not just in hospitals, it's everywhere," says team leader Andrew Boulton at Manchester University.
Antibiotics prove useless against these bugs. So Boulton decided to turn his attention to maggots. These creatures have been called into action to chew up infected tissues ever since the American Civil War, and have been used in diabetes clinics for a decade. Boulton wanted to see how they fared against MRSA.
A small initial trial, published this February, showed considerable success1. 'Larval therapy' (the polite term for maggot treatment) was excellent for shifting MRSA infected tissue: in 12 out of 13 patients, their wounds healed after between three and five applications of maggots, each lasting four to five days. "It's primitive but effective," says Boulton.
The charity Diabetes UK has now given Boulton £98,000 (US$195,000) to test maggots versus two other treatments: silver-containing dressings and a biogun — which zaps infection by ionizing molecular oxygen and creating bug-beating superoxide radicals. The trial will involve a total of 65 patients and will begin within a few months. Boulton expects the maggots to fare the best: "We hope that this trial will confirm our findings," he says.
The trial has been temporarily held up because the UK's Medicines and Healthcare products Regulatory Agency claims that the ancient maggot-healing technique is a new therapy that requires a special licence. But Boulton expects to overcome this hurdle within a few weeks.
Boulton is also collaborating with microbiologists to find out how the treatment works. The maggots might secrete an antibacterial goo, or they might be just devouring the infected flesh. Boulton has noticed that the MRSA infection is highly concentrated around the maggots — rather like iron filings around a magnet, he says. But at the moment how and why this happens is a mystery.
- Bowling F. L., Salgami E. V., Boulton A. J. M., et al. Diabetes Care, 30 . 370 - 371 (2007).