The New Future of Antibiotic Therapy
by Olivia Parks
On September 28, 1928 in St. Mary’s Hospital in Paddington, London, Bacteriologist Dr. Alexander Fleming made a seemingly trivial observation. One of his Petri dishes has an unusual mold-like substance growing on it. Fleming thinks nothing of it at first. However, by chance, his mucus drips into one of these mold-infested plates as he places them to the side of his lab bench. He plans to soak the Petri dishes in Lysol the next day to eliminate the mysterious mold. Upon returning to his lab the next morning, Fleming sees that the bacteria from his mucus is growing on the Petri dish but the white, fluffy mold has killed the bacteria in several areas.
Dr. Alexander Fleming has just made one of the most important discoveries in the history of medicine: the first antibiotic, penicillin.
Today, there is a family of 16 different antibiotics in the penicillin family, including ampicillin (commonly used to treat ear and bladder infections), amoxicillin (which treats strep throat infections), oxacillin (a stronger antibiotic used for staph infections) and cloxacillin (an antibiotic that treats numerous types of infections).
For decades, the explosion of the antibiotic drug industry has saved thousands of lives, limbs and livelihoods. However, a growing problem in twenty-first century medicine is that these bacteria, which were once so easily killed by antibiotics, have become drug-resistant. As bacteria change their genetic sequence, they are able to survive in the presence of these antibiotics. Many bacteria have life spans of only days or weeks, meaning that they can undergo evolution much faster than humans can develop and test new drugs.
Figure 1 illustrates this phenomenon. The Petri dish on the left displays white circles of paper soaked in different antibiotics. The bacteria, growing in a white film on the surface of the Petri dish, are unable to grow close to the paper circles since the antibiotic kills the bacteria. However, the Petri dish on the right shows bacteria that has become drug-resistant to the antibiotics and is able to grow all around the paper circles.
The unanswered questions remain: How do we fight these bacteria? What happens when our strongest antibiotics no longer stop an infection from spreading?
Biology professors, Kim Lewis and Slava Epstein, might have an answer. Teixobactin, a drug recently discovered by Lewis, Epstein and their team of researchers at Northeastern University in Boston, was developed using a new technique to study the effects of this drug on bacteria. After nearly a decade of research, iChip, a technology used to formulate and study antibiotics such as Teixobactin, was created.
A small sample of soil, which contains millions of different bacteria and fungi, is diluted and poured onto the iChip machine. The iChip apparatus is composed of hundreds of small holes. Since the soil is diluted and run through the holes, the goal is to have one bacterium caught in each of the holes at a time. Once the microbes have been captured, membranes are arranged around the iChip and the whole structure is placed back into the sample of soil. The membranes are selectively permeable. This means that nutrients and water from the soil can pass through the membrane and reach the microbe inside the hole, but the microbe is unable to pass through the membrane and leave the enclosure.
In this way, Lewis and Epstein were able to study a single bacterium’s consumption of nutrients as well as the exact process of asexual reproduction. Learning the bacterium’s reproductive pattern was essential for Lewis and Epstein’s research as they were able to analyze the “mutations gained by the bacteria during the process.” Through this process, they could successfully isolate the antibiotics the bacterium itself had produced as part of their natural chemical defense mechanism.
The bacterium Eleftheria terrae was studied in the iChip. Lewis and Epstein first isolated the antibiotic that the bacterium produced using the iChip. Consequently, they found that when this antibiotic was used against the bacteria, it successfully eliminated the entire population of E. terrae. This antibiotic became known as Teixobactin.
Since its discovery, scientists learned that the antibiotic only kills Gram-positive bacteria. Gram-positive bacteria have a specific cellular composition that distinguishes them from their Gram-negative counterpart. Gram-positive bacteria cause infections such as diphtheria and tetanus while Gram-negative bacteria cause urinary tract infections, wound infections (which can lead to gangrene) and gonorrhea. While Teixobactin has been proven to treat disorders via animal studies, it is by no means a cure for all infections. Perhaps the more important breakthrough here was how scientists approach the creation of new drugs: exploiting naturally occurring cellular defenses.
Lewis is now working with NovoBiotic Pharmaceuticals to set up the first clinical trials for Teixobactin. While it is difficult to predict when clinical trials will begin, Lewis predicts that this drug could be distributed for widespread use in the next 10 years.
Further research and implementation of iChip methods are seemingly endless. “Rarely is a discovery made that improves the health of human beings around the globe,” said Joseph E. Aoun, President of Northeastern University. “Professor Kim Lewis and his team have made history with their discovery in a field that has not seen a breakthrough in nearly three decades.”