Antibiotics, first discovered in 1929 by Alexander Fleming, are a class of medications that kill microbes like bacteria, parasites and fungi. The most well known, and first, antibiotic is penicillin which was originally isolated from the fungus Penicillium when Dr. Fleming noticed the fungus could kill disease causing bacteria. Many antibiotics are initially isolated from bacteria and fungi who evolved to produce the compound as a way to defend themselves from other bacteria. Since penicillin was first used around 1940 to treat bacterial infections, deaths from infectious diseases have fallen from around 200 per 100,000 per year to below 50 per 100,000 per year today. This decline was in a large part thanks to antibiotics but also to the introduction of vaccines.
Today, however, we are faced with a problem that is growing rapidly and costing people their lives. The once magic bullet antibiotics are beginning to fail because bacteria and other microorganisms are beginning to develop resistance to them. Diseases like tuberculosis, malaria and staph infections are becoming harder and harder to treat. Resistance to antibiotics or antimicrobials can occur when they are taken as a treatment for which they are not needed; for example, antibiotics will do nothing to treat the common cold or flu but many doctors will prescribe them when met with a patient who demands a treatment for their cold. Similarly, the overuse of antibiotics in agriculture, cleaning products and hospitals allows for the potential generation of resistant microbes. As a result of all this resistance, bacterial and microbial infections are becoming harder and more expensive to treat. As well, new antibiotics are becoming increasingly costly and time consuming to develop.
A group of researchers may have found an answer to helping us treat microbial diseases without the potential risk of developing microbial resistance. The work, published in Nature Biotechnology, centred around the use of liposome’s, basically a bubble made from the same stuff as your cells coating (lipids). They created liposome’s that had a similar composition to that of your cells membrane and found that they could suck up bacterial toxins before they harmed your cells. These bacterial toxins act by poking holes in your cells membrane and allow precious proteins and resources to leak out, think of a balloon with several small holes in it. If these toxins are sucked up by the liposomes, they can’t attack your cells and prevent the damage done by infections. When the researchers treated mice that had been infected with various bacteria with these liposomes, they found that they had increased survival compared to the mice without the liposome’s who usually died with 24 hours. They also found that these liposomes increased the effectiveness of traditional antibiotics meaning the two treatments could be used together to tackle particularly tough infections.
The liposomes are made from different types of fats found within a cells membrane (including cholesterol) and as such have already been shown to be safe for human use. Liposomes are already being investigated for use in more efficient drug delivery for cancer or other diseases. This type of treatment is unlikely to result in the type of resistance we see with other types of antibiotics because it doesn’t directly kills the bacteria, instead it leaves them vulnerable to attack from immune cells that would normally be killed by the toxins. However, there is no guarantee that resistance wont develop and so more research looking into if resistance can develop is needed. It will also be important in knowing whether this treatment can work on already resistant bacteria like MRSA (methicillin-resistant staphylococcus aureus) or VRSA (vancomycin-resistant staphylococcus aureus) or on parasites like malaria. Finally, human trials are a ways off as more safety and efficacy work in animals needs to be done, but if human trials succeed, this may be what we need to help turn the tides against the rising tide of resistant bacteria.