Researchers presented findings on the prevalence of the mcr-1 gene, a transferable genetic mechanism of antimicrobial-resistance to colistin - the last resort antibiotic in a number of circumstances. At a session dedicated to late-breaking abstracts on colistin resistance, researchers presented evidence on the prevalence of the gene in bacteria (including Enterobacteriaceae such as Escherichia coli,Salmonella or Klebsiella). Scientists also presented evaluations of treatment and management options, as well as new diagnostic methods and assays to help identify mcr-1. The late-breaking data was released at ECCMID 2016 – the annual meeting of the European Society of Clinical Microbiology and Infectious Disease (ESCMID).
The mcr-1 gene is particularly significant as it can be carried by plasmids, small DNA molecules, which can be transferred between single-celled organisms, such as bacteria, through so-called horizontal gene transfer. These genes can then be transferred sideways to other strains or species, not just vertically down to the offspring by replication. Horizontal gene transfer is the primary reason for antibiotic resistance.
The mechanism, first discovered in an E. coli strain from a pig in China in November 2015, has over the past months been identified in bacterial samples across the world. The increased prevalence of plasmid-mediated resistance is causing major concern among infectious disease specialists, because it threatens to reduce options to treat infections and is creating new resistant bacterial strains.