Chinese researchers found a gene in Escherichia coli (E. coli) that protects the bacteria against colistin – an antibiotic which is considered to be a last resort, since the bacteria have evolved to be very resistant to antibiotics.
Jian-Hua Liu, a professor at South China Agricultural University in Guangzhou, said that the results of the study are extremely worrying, especially because that specific gene can be easily transferred from one microbial species to the other.
If the bacteria were to become resistant even to the last-resort antibiotics, humans would be left vulnerable to possible epidemics that doctors could not treat.
In the study – published November 18 in the journal The Lancet Infectious Diseases – the researchers discovered the mcr-1 gene in samples of Escherichia coli that were taken from pork products, pigs, and people infected with the bacterium.
They found that mcr-1 protects E. coli against the colistin antibiotic. According to the researchers, the mcr-1 gene was most prevalent in samples taken from pigs, rather than humans, suggesting that it may have first developed in livestock.
Dr. William Schaffner, professor of preventive medicine and an infectious disease specialist at Vanderbilt University Medical Center in Nashville, Tennessee, said that after its discovery in 1947, colistin was widely used through the 1960s. However, because of its toxic effects on the nervous system and on the kidneys, the doctors stopped using colistin and turned to safer antibiotics.
Because colistin was not used for so many years, the bacteria did not have the opportunity to become resistant to the antibiotic, Dr. Schaffner stated. Thus colistin could have been one last reliable antibiotic to fight against bacterial infection, he added. Unfortunately, the new study has found a colistin-resistant gene in E. coli.
Antibiotics can only fight bacterial infections, which is why people should not take them when they are not needed, because it give the bacteria a chance to become resistant to them, Dr. Schaffner stressed.
Currently, the drug-resistant bacteria have only been found in China, but researchers warned that the gene could spread, which is why close internal monitoring of the gene is needed. Good hand hygiene is now more important than even to prevent bacterial infections, the researchers advised.
Dr. Amesh A. Adalja, an infectious disease specialist and senior associate at the University of Pittsburgh Medical Center’s Center for Health Security, said that the use of antibiotics will always encourage bacteria to evolve and survive, something that they have been doing for more than three billion years.
Image Source: c1.staticflickr
Share this:
