|Fig 1: MCR-1 detection in China. Source|
Just a couple of weeks ago, I wrote a blog-post on MCR-1 (Mediated Colistin resistance). The first time demonstration of the gene in plasmid has pulled the attention of Clinical microbiologists worldwide. There was a lot of discussion on what this means. Fig 1, from original paper summarises the surveillance data, the extent of spread in China.
The hope was that this hasn't spread as of yet. A study team from Denmark discovered the presence of the new resistant bacteria by searching for it in a database containing the genetic sequences of about 3,000 E. coli samples. According to the announcement MCR-1 was found in one patient, who suffered from a blood infection in 2015 and in five food samples that have been imported from 2012-2014. The Patient was Danish who hasn't travelled outside and the other 5 samples are from poultry that was imported from Germany. That means there are at least 4 countries where this plasmid gene is sitting- China, Malaysia, Denmark and Germany. Paper yet to be published
Frank Aarestrup, head of the genomic epidemiology group at the National Food Institute, comments, “I was not surprised but I had really sincerely hoped not to see it”. In a statement issued by Antibiotic Resistance Action Centre, Source
The news that the dangerous colistin resistance gene has been found in Denmark is alarming. This newly identified gene, called MCR-1, is on a mobile piece of DNA that can make copies of itself and then jump to from bacterium to bacterium, spreading resistance. History shows that these mobile resistance genes can spread around the world quickly, silently riding in people, animals, and food. The news that MCR-1 has been discovered in Denmark suggests that this scenario is playing out in real time.
In the latest, there is a lot of discussion about surveillance and many different groups have already started to look into evidence of this gene in their colistin resistant strains. Some people are calling it the next NDM and have opinions on the likely global spread already.
Liu, Y., Wang, Y., Walsh, T., Yi, L., Zhang, R., Spencer, J., Doi, Y., Tian, G., Dong, B., Huang, X., Yu, L., Gu, D., Ren, H., Chen, X., Lv, L., He, D., Zhou, H., Liang, Z., Liu, J., & Shen, J. (2015). Emergence of plasmid-mediated colistin resistance mechanism MCR-1 in animals and human beings in China: a microbiological and molecular biological study The Lancet Infectious Diseases DOI: 10.1016/S1473-3099(15)00424-7