New antibiotic-free method to treat infections

There have been increasing numbers of different types of bacteria that have become resistant to some antibiotics: Tuberculosis, some forms of Staphylococcus aureus, some Enterococci, strains of gonorrhea and others. The “classic” antibiotics that used to kill these organisms, quite quickly and nicely now no longer work.

Sometimes now, combinations of antibiotics need to be used simultaneously, sometimes for weeks at a time. Or perhaps a brand new antibiotic needs to be given.

Formerly, many of the above infections could be treated with oral medications, some minor ones could have been treated with antibiotic creams. Now the antibiotics often have to be given intravenously. Even with all of this technology (combining antibiotics, using newly developed antibiotics, giving them IV), sometimes the bacteria still win and the patient may die.

Researchers in Switzerland have come up with a different approach that sometimes may not even require antibiotic use.

Antibiotics via Shutterstock

Antibiotics via Shutterstock

Some bacteria kill and injure cells by producing toxins that damage human’s cell membranes. Once a hole is produced in the cell membrane, the cell almost always dies. The injured cell has a great deal of difficulty keeping out what should be kept out and reigning in what needs to stay inside. Too much of substance X leaks out, too much water gets in, potassium levels change and the cell expires.

When the bacteria are growing, they release toxins into the environment. A white blood cell coming to the defense of its sister cells has bacteria; toxin stick to it, and is destroyed — much like surrounding tissue cells. So, if we could neutralize the bacterial toxins, they wouldn’t be able to attack the immune cells as those cells close in on the invading bacteria.

What the researchers did was to create tiny vesicles that could attract toxins, just as cell membranes attract toxins. But once the toxins bound to this artificial liposome, there were stuck and couldn’t attack any surrounding human cells. As more liposomes sucked up toxin, there was less available to bind with and destroy healthy cells like white blood cells. The white blood cells could then attack and destroy the invading bacteria and eventually clear up the infection. Many times this would occur in the absence of any antibiotics at all being given.

The liposomes are basically just microscopically-sided droplets of naturally-occurring fats that can attract and bind some bacterial toxins. They act as a “toxin-decoy.” The toxin comes into contact with the liposome, then physically can’t tell if it is a liposome or a part of a cell membrane. It binds there and becomes useless.

The scientists have used this technique in mice. It’s worked against infections with two different types of bacteria: Staphylococcus aureus and Streptococcus pneumoniae. In both cases, experimental infected mice, given the liposomes, survived the infections, even when NOT given antibiotics, while the control mice died.

Perhaps, if necessary, when used in humans the liposomes could be added to antibiotics in very severe, life-threatening infections, if needed. Thereby both attacking the bacteria and attacking one of their weapons at the same time.

So far this technique can only work against certain specific bacteria . They need to be Gram positive and produce cytotoxins that can be inactivated by the liposomes. But the authors are continuing their work to see if it can be applied to other organisms.

The equally amazing news is that, since the liposomes aren’t antibiotics, the bacteria can’t become resistant to them. That has been a major problem with resistance in the past.

These researchers deserve this year’s award for Thinking Outside of the Box.

Mark Thoma, MD, is a physician who did his residency in internal medicine. Mark has a long history of social activism, and was an early technogeek, and science junkie, after evolving through his nerd phase. Favorite quote: “The most exciting phrase to hear in science... is not 'Eureka!' (I found it!) but 'That's funny.'” - Isaac Asimov

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