The Antibiotic That's Not An Antibiotic
A new and promising tool is being developed in the war against bacterial infections that use liposomes to sequester bacterial toxins which minimizes dramatically the possibility of increasing bacterial resistance over time.
The widespread and frequently unwise use of antibiotics the past couple of generations has been incredibly short-sighted and frustrating. The Centers for Disease Control (CDC) has stated that almost half of human antibiotic use is unnecessary and inappropriate making it the most potent cause of increasing antibiotic resistance. The use of antibiotics on animals is a huge problem as well. The most galling example for me is the often fruitful and ridiculous insistence of many people for antibiotics for viral infections. Couple that with other improper use like not finishing a prescribed course of antibiotics and what we have been essentially doing is accelerating the evolution of harmful bacteria. Some infections have become so resistant that doctor’s have to more frequently resort to less effective more toxic alternatives. If they fail the doctors have very powerful last-line-of-defense antibiotics like Carbapenem but even they have begun to fail.
We appear to be inexorably heading then back to a truly terrifying pre-antibiotic era in which most infections could be deadly. Some bacteria in fact are already in this era since there’s nothing left that can defeat them.
The prospect for the future development of new antibiotics doesn’t look rosy either considering that the environment these drugs need to be created in is working against them. American medical researcher Dr. Henry Miller had the following to say about this:
At the same time that bacterial resistance to antibiotics is increasing, the number of drug and biotech companies developing new antibacterials is shrinking. This decline is due to a number of factors, including lack of industry productivity, the low return on investment of antibacterials compared with other therapeutics, difficulty in identifying new compounds with traditional discovery methods, regulatory requirements that require large and complex clinical trials for approval, and initiatives that encourage antibiotics to be used as sparingly as possible (to minimize the spread of resistance).
Yet, it’s not all doom and gloom. Researchers at the University of Bern announced recently that they have created a new approach to dealing with severe bacterial infections that not only looks promising but neatly side-steps the potential of bacterial resistance. They achieved this by engineering nanoparticles to form liposomes which resemble the membranes of cells. In the past, liposomes have been used successfully to deliver specific kinds of medicine into people’s bodies. These liposomes act as decoy cells which make them a potent lure for the bacteria which attach to them once they’re close enough and sequester their exotoxins inside. Depleted of their insidious weapons, the bacteria are then much easier for the body to deal with naturally. The toxins themselves are also safely eliminated without risk to normal healthy cells. Moreover, since the bacteria are not directly attacked, there is no selective pressure for them to evolve resistance.
As promising as this method looks, keep in mind that it’s only been tested in mice so far. The results were very positive but the researchers have a long road ahead them to prove efficacy in humans and then roll it out to the general public. As usual, any number of things could go wrong especially when those masters of Darwinian evolution, bacteria, are involved. Another caveat, many of the most virulent bacteria produce exotoxins but not all do, so using liposomes in this way will not be effective against them all.
And finally, it’s important to stress that this liposome strategy is so different than other methods that’s it’s not even technically an antibiotic. This is exactly the kind of out-of-the-box strategies we need to defeat these buggers and may be the best thing…at least until we create nanite hunter-killers.
Image Credit: http://ianjuby.org/newsletter/?p=194