Multidrug-resistant bacteria may be here to stay. The common wisdom that superbugs with antibiotic resistance are outcompeted by their non-super neighbours in the absence of antibiotics has been turned on its head. Bacterial antibiotic resistance is a major concern because it can lead to the appearance of dangerous and difficult-to-treat infections in humans. Resistance generally occurs in one of two ways: either through mutations in the bacterial DNA or, more commonly, through the acquisition of resistant genes from other organisms through horizontal gene transfer. In both cases, previous studies had found that the superbugs lose their competitive advantage once the antibiotics are no longer present. For instance, a voluntary ban by Danish farmers on the use of antibiotic growth promoters in chicken and pigs cut antibiotic resistance in the bacteria within the animals by over 90 per cent.
