Scientists discovered that a specific gene, which was found last year and inducing resistance to the last resort antibiotics has spread further than previously anticipated. The latest findings show the mcr-1 gene that can resist the last resort antibiotics of colistin has spread worldwide.

Since the mcr-1 gene was detected for the first time in 2011, researchers found the presence of this gene in a strain of e-Coli bacteria found in pigs almost two years ago in China. The gene has also been found in many strains of bacteria and promoted a resistance to colistin, dubbed as the last resort antibiotics. Currently, the gene has been found in many strains of bacteria around the world at an alarming rate, as reported in many presentations during the Microbe 2017, an annual meeting for the American Society for Microbiologists in New Orleans from June 1 to 5.

In some places, according to Scientific American, nearly 100 percent of farm animals carries the mcr-1 gene. An antibiotic researcher at the George Washington University, Lance Price said that the spread of mcr-1 has shown how the use of antibiotics on farms can lead to resistance in human infections.

Colistin, known as "last resort antibiotics" or "last ditch antibiotics" was discovered in 1949 and became available for clinical use since 1059. This antibiotic is rarely used to human, while in many countries, colistin was used to promote livestock growth. Unfortunately, such practice has led to the emergence of colistin resistance gene mcr-1 in e-Coli bacteria which was first discovered in 2015.

Afterward, microbiologists found more cases of the mcr-1 gene in other strain of bacterial species. Beside in E-coli strain, mcr-1 was also found in Salmonella enterica, Klebsiella pneumonia, Enterobacter aerogenes and Enterobacter cloacae. The presence of this gene in that bacteria has created an emergence of the superbug, that showed resistance to colistin, the last resort antibiotics.

The mcr-1 is a plasmid-borne gene which was first detected in 2011. Beside its resistance to colistin, mcr-1 is also found to develop resistance to some microbes from the human immune system.