New resistant gene found in Canada and health professionals are taking note

It has been confirmed that the antibiotic resistant gene MCR-1 has been identified in Canada.

Whether it is found in people, plants or bacteria, a gene is a little piece of genetic structure — of DNA.

MCR-1 is a gene that has been making headlines recently because it is resistant to treatment using antibiotics, meaning there is no known treatment for the bacterial infections that contain the gene.

 This notable gene can be found in the plasmid, a little piece of DNA that has the ability to jump from one bacterium to another.

So, if one type of bacteria has the MCR-1 plasmid, and if that specific bacteria gets into a different population of bacteria, the recipient bacteria can then acquire the same type of antibiotic resistance. And this transfer or migration can potentially be repeated over and over.

“As long as [MCR-1] stays in normal bacteria that don’t cause disease, then that’s okay. The problem would be if [MCR-1] jumped into a bacteria that does cause disease [making it] resistant to other antibiotics. Then that would be an issue,” said Glen D. Armstrong, professor in the University of Calgary’s department of microbiology, immunology and infectious diseases.

“So far, I don’t think that’s been detected, but you know, that’s the concern.”

Currently, MCR-1 hasn’t been found in any deadly bacterial bugs in humans, only in bacteria that naturally exist in and on our bodies.

Colistin is a “last resort” antibiotic, used to treat very specific bacterial infections. The MCR-1 gene is resistant to this antibiotic. This treatment is regarded as a last resort because of its poisonous affect on the recipient’s kidneys.

“Colistin is one of the last antibiotics that we have available for treating infections where the bacteria have acquired resistance to multiple other antibiotics, also known as superbugs,” Armstrong said.

Antibiotic resistance

Microbiologists have previously seen resistance developed to colistin, the gene mobilizing, however, is recent.

The MCR-1 gene is resistant to antibiotic treatments, much like MRSA, the antibiotic resistant strain of Staphylococcus that is resistant to most antibiotics, shown above in green interacting with human cells.
Creative Commons image courtesy of NIAID.
Antibiotic resistance has been mentioned by authority figures such as United Kingdom Prime Minister David Cameron, who has gone on record to warn of the, “Medical dark ages,” or an age when antibiotics can no longer level the playing field against infections and superbugs.

Armstrong, however, disagrees with this, “Doomsday hypothesis.”

“I think that we have to be careful,” he said. “We know a lot about how microbes become resistant now, and one of the big problems that we’re facing is … antibiotic stewardship. [This means] only prescribing the proper antibiotics when they’re needed, not over prescribing them. One of the other things is not using antibiotics in agriculture as growth promoting drugs, which has been a big problem.”

Antibiotic issues in the global village

The world as a global village is an aspect of antibiotic resistance as well.

Armstrong said that developed countries adopting strong antibiotic stewardship is one thing, and that would certainly start to limit the spread of antibiotic resistance.

Not all countries in the world operate the same way, however. If other areas of the world continue to use antibiotics to promote plant growth in their agriculture, for example, then antibiotic resistance is going to continue to evolve in those regions, he said.

The iChip now allows microbiologists to grow bacteria found in soil that were never able to be grown in a lab environment before.
Creative Commons image courtesy of The Natural Resources Conservation Service (NRCS) Soil Health Education and Awareness Effort.

“Because of the practice of medical tourism, [which is] where people will leave their country and go to, say, India… to have a medical procedure done, and then they bring that bacteria back with them to North America and it gets introduced.

“So, because we’re now a global village, and bacteria [doesn’t] recognize national borders, [they] are quite happy jumping onto a susceptible host— and if that host insists on flying around the world, then the bacteria will spread that way.” Armstrong said.

China, where the MCR-1 gene was originally identified, is struggling with antibiotic resistance as well.

“I think that it’s quite alarming, the number of thousands of metric tonnes of colistin that are used in China’s [agriculture industry]. So that was kind of the reason I think this gene got mobilized and became a problem,” said Armstrong.

“I think the Chinese authorities have recognized this and are doing something to eliminate the use of colistin in the agriculture industry, meanwhile the genie’s a bit out of the bottle.”

Hope on the antibacterial horizon

There is a back-up plan when it comes to bacteria like MCR-1 that are resistant to colistin, and other traditional antibiotics, however.

Teixobactin is a new antibiotic in development that targets gram-positive bacteria, such as Methicillin-resistant Staphylococcus aureus, which is more commonly known as MRSA.

This new antibiotic was discovered using groundbreaking technology called the iChip, which made it possible for microbiologists to grow bacteria that they could not previously grow in labs.

“Basically, microbiologists have become like prospectors. If you can find one promising antibiotic like teixobactin in soil bacteria, there’s billions and billions of different species of soil bacteria, and we’ve only just scratched the surface of being able to grow these bugs. There’s a huge potential there for discovering many other new antibiotics,” said Armstrong.

Alberta government and the plan for MCR-1

In an email, Dr. Martin Lavoie, acting chief medical officer of health of Alberta stated:

“The discovery of MCR-1 in Canada underscores the importance of work underway provincially, nationally and internationally to combat antimicrobial resistance. To date, there has been no screening for MCR-1 in Alberta— or anywhere else in Canada— outside Ontario.

“Further investigation is needed before it can be confirmed whether the gene is present in the province. The Government of Canada is leading national efforts to prevent, limit and control the emergence and spread of antimicrobial resistance.

“In Alberta, Alberta Health provides funding to Alberta Health Services for initiatives such as the Antimicrobial Stewardship Program, which promotes and supports the safe and effective use of antibiotics in the province’s health care system, to help preserve the value of antibiotics.”

Dr. Lavoie also recommends that the public reduce infection risks through proper hand washing and by following guidelines for safe food handling and preparation.

trathgeber@cjournal.ca

The editor responsible for this article is Cheryl Russell, crussell@cjournal.ca