That antibiotic use fuels the rise of resistance in bacterial populations is well understood. What is less well understood is where the antibiotic resistant genes come from in the first place. Some have argued that modern antibiotic resistant traits have evolved when bacterial populations come under intense selective pressure from drugs. Others have argued that antibiotic resistant traits have always been present in wild bacterial populations and that as human use of drugs has increased this has driven the distribution of these traits to dramatically rise. Now the discovery of a worryingly resistant bacterium from Antarctica is providing strong support for the argument that resistant traits have always been around.
Antibiotic contamination in Antarctica is almost nothing. Yes, it is possible that a bacterium from a more antibiotic contaminated region of the world could migrate there through the sea, the rain or human activity but this is widely viewed as unlikely. It is for this reason that the discovery of an unstoppable bacterium on the frozen continent is so surprising.
The species that has been found belongs to the genus Pseudomonas, the group that contains the highly troublesome Pseudomonas aeruginosa that routinely causes lethal resistant infections in nursing homes and hospitals. Yet, while P. aeruginosa is found all over the developed world and has had ample exposure to antibiotics over the years, the new species, creatively named 6A1, has never been seen by science before and appears to only occur in Antarctica.
If 6A1 was only resistant to one or two antibiotics, that would not be particularly noteworthy but this is not the case. The bug is resistant to a lot of antibiotics and extremely resistant to a number of the best drugs on the market today. I won't get into all the details here, but its resistance to the common antibiotics amoxicillin and cefoxitin was far greater than that seen in P. aeruginosa. Resistance to erythromycin was ten times greater than that seen in P. aeruginosa. Worse, against ertapenem, a state of the art last resort antibiotic, the new species proved 180 times more resistant than P. aeruginosa.
Let us all hope that 6A1 remains sequestered in Antarctica for a very very long time.
This research published online in Polar Biology and, while I could not weave it into the science section of The Economist, you can view the original peer reviewed paper here.