Blast from the Past: Antibiotics Past and Present

Caroline Ayinon
By Caroline Ayinon August 17, 2016 18:37

Blast from the Past: Antibiotics Past and Present

With antibiotic resistance on the rise, researchers are frantically searching for ways to counter new bacterial “superbugs.” Instead of looking for new state-of-the-art solutions, researchers might have more success dusting off ancient medieval texts. Just last summer, scientists discovered that a one-thousand-year-old garlic and onion remedy for eye infections may hold the key to treating certain antibiotic-resistant infections.

 

A team led by Freya Harrison and Steven Diggle at the University of Nottingham tested the remedy, found in a 10th century Anglo-Saxon manuscript, against methicillin-resistant staphylococcus aureus (MRSA). While the individual ingredients were known to hold limited antibacterial potency, when combined, they were able to consistently kill up to ninety percent of MRSA bacteria. “The fact that the whole recipe—all the ingredients and the specific preparation instructions—is required to make the mixture work is fascinating,” said Harrison. “It suggests that there might have been some empirical method present in at least some of the medical treatments that early medieval people developed.”

 

Prior to this study, experts considered the efficacy of other medical interventions from antiquity, but few quantitative studies had empirically proved their abilities. Harrison and Diggle’s work has demonstrated that further exploration of seemingly outdated therapies may help to improve current medical treatments. According to Diggle, they are still looking into other historical texts for effective medicines. “Our ancestors have done experiments for us and so these books are an extremely useful starting point,” said Diggle.

 

Bacteriophages attach to their target cell to destroy it. Image courtesy of Graham Beards.

Bacteriophages attach to their target cell to destroy it. Image courtesy of Graham Beards.

Medieval potions are not the only promising historical treatment: A look into the more recent past has led scientists to consider bacteriophage therapy as a tool for fighting infections. Bacteriophages are viruses that infect and kill bacterial cells. However, bacteriophages are unable to infect human cells and so were used to treat a variety of infections in the 1920s and 1930s. Although physicians of the time did not fully understand how bacteriophages functioned—and therefore did not always design the most effective treatments—bacteriophage therapy was an important tool to fight infections prior to the emergence of antibiotics.

 

Since the advent of antibiotics, their use has skyrocketed. Today, antibiotics are often used in excess to treat patient infections or to increase agricultural productivity. (2) Consequently they drive the evolution of antibiotic-resistant strains of microbes, like MRSA. Antibiotic resistance affects millions of people who cannot obtain drugs to effectively treat their infections. It is a serious threat to medicine, and researchers are now exploring alternative treatments, like bacteriophage therapy, for infectious diseases.

 

Bacteriophage technology is currently used to target foodborne illness, which affects approximately 9.4 million people in the United States each year. One biotechnology company, Intralytic Inc., has been designing medical interventions against pathogenic bacteria since 1998. The company recently created two products—ListShieldTM and EcoShieldTM—that combine bacteriophages targeting the same bacterium. Both of these products are designed to kill bacteria during food processing. ListShield is now an FDA approved food additive, and it targets Listeria monocytogenes, an infection-causing bacterium found on dairy products, meats, and raw produce. This bacteriophage “cocktail” kills pathogens after it is sprayed directly onto food or other areas of a food processing plant that may harbor the bacteria, like drains or floors. EcoShield is similar to ListShield, but it targets Escherichia coli, a bacterium responsible for 62,000 cases of foodborne illnesses every year. Both products are harmless to everything except the bacteria they were engineered to target.

 

Another newly emerging bacteriophage technology relies on the isolation of enzymes called lysins. When bacteriophage target a bacterial cell, they produce lysins that cause bacterial cells to rupture. Scientists recently discovered that lysins effectively fight certain bacteria independently, without other components of the bacteriophage. Bruce Seal, a researcher for the US Department of Agriculture, has successfully used lysins to kill strains of Clostridium perfringens, a bacterium that causes food poisoning in humans and necrotic enteritis in poultry—a disease that devastates the poultry.

 

From medieval eye remedies to bacteriophage technology, history may offer us the tools needed to help fight modern disease. Despite recent innovations, a blast from the past may be needed to solve some of today’s most challenging puzzles in medicine.

Caroline Ayinon
By Caroline Ayinon August 17, 2016 18:37