When battling multiple antibiotic resistant infections, what
should we do when our last line of defense fails us? We may be frantically
searching for an answer a bit sooner than we’d hoped: New research published
just a few weeks ago shows that plasmid-mediated resistance to colistin has
been discovered amongst livestock in China. Uhh…Colistin? Well, there’s
probably a reason you’ve never heard of it. Colistin belongs to a very strong
class of polymyxin antibiotics, which have cationic polypeptide structure, and
are reserved for only the most serious infectious disease cases. Notably,
colistin is not a new antibiotic, but side effects like kidney damage and
bleeding discouraged widespread use since its discovery in 1959. Unfortunately,
it has been more widely used in livestock, particularly in developing countries
like China. (Side note: 8 out of 10 of the largest world colistin producers are
Chinese.) Some of the most serious livestock infections are the result of
carbapenemase-producing Enterobacteriaceae, treatable only with colistin. Up
until now, colistin resistance was due to chromosomal mutations, but the huge
rise in resistance in China has recently been determined to be
plasmid-mediated. What’s the big deal with that? Plasmid transmission allows
the easy spread of the resistance gene from cell to cell and even across species.
The resistance gene mcr-1 has been transferred
in plasmid pHNSHP45 between strains of E.
coli, K. pneumoniae, and P. aeruginosa, and researchers have even found the resistance gene present in human samples collected at an inpatient
facility in Guangdong, China.
This brings us to the paradox of using antibiotics: if we
use them, are we fated to eventually create more dangerous strains of
antibiotic-resistant bacteria? Does using antibiotics at the rate we do ensure
that we find ourselves in a pre-antibiotic era?
Very interesting article. The concept of antibiotic resistant bacteria certainly isn't a new one, but the fact that it is now developing against rarely used drugs for the most serious infections is particularly concerning. The antibiotic-resistance epidemic is one that I don't think a lot of the general public is aware of, and one that stems from many causes, meaning a complex solution. I think a lot of it is from over-prescription of antibiotics by doctors, and failure of people to properly take them allowing the bacteria to develop resistance. But I think a lot, as your article mentioned, is from all of the antibiotics that are added to animal feed, and can then make the jump across species. But, coming from a very rural agricultural background, I can tell you it is going to be hard to get livestock producers to stop feeding their animals this antibiotic-laced feed when it means more healthy animals and in turn, a bigger profit. I think a lot more funding needs to be done to get farmers more educated and aware of the problems feeding their livestock this feed causes, otherwise, like you said, we might end up in a time where no antibiotic proves effective.
ReplyDeleteIsabel,
ReplyDeleteI find the "antibiotic paradox" you mentioned here to be an incredibly fascinating one. As Travis mentioned above, it seems as though the extensive use of antibiotics in agriculture is a pattern that doesn't show signs of changing any time in the near future. Consequently, the inevitable emergence of antibiotic resistance bacteria will seemingly have to be battled through the development of new antibiotics. Considering the extensive laboratory and clinical testing that is required for the development of a new drug, this is an incredibly difficult feat on its own; unfortunately an episode of "Vice" that I recently saw demonstrated how that task might become even more difficult. The episode points out that developing new drugs relies on the discovery of naturally occurring substances that have developed in organisms to fight off bacteria over millions of years of evolution. Importantly, the Indonesian rain forests are some of our most valuable resources for these naturally occurring substances, and that's where things get worse. Deforestation of rain forest is a huge problem in Indonesia due to the high demand for Palm Plantations. This rampant deforestation is rapidly depleting the resources for our super-bug fighting antibiotics. The sad truth that follows: it appears as though we might indeed be on our way to a post-antibiotic era as long as antibiotic use rises and our natural resources fade away.
This is a really interesting episode, here's the link: http://hbowatch.com/vice-the-post-antibiotic-world-indonesias-palm-bomb/