By Will Howell
Antibiotic resistant bacteria is a growing concern for public health. Due to many factors, such as over-prescription, failure to finish courses, and uses in animal agriculture, antibiotic resistant bacteria are steadily increasing. This is a serious concern, as antibiotics have long been the first line of defence against bacterial infections. For example, the Centers for Disease Control and Prevention estimate more than 2.8 million antibiotic-resistant infections occur in the U.S. each year, and more than 35,000 people die.
However, a group of researchers at McMaster University have discovered two new antibiotics, corbomycin and complestatin, that might give cause for optimism. Traditional antibiotics, such as penicillin, kill bacteria by breaking down the cell wall that surrounds them. These novel antibiotics work in a completely different manner, by blocking the breaking down of the cell wall. As bacteria reproduce by duplicating and dividing, a process known as binary fission, preventing the cell wall from breaking down inhibits the bacteria’s ability to reproduce.
Beth Culp, a PhD candidate at McMaster University and first author of the study that published the findings, explains that “Bacteria have a wall around the outside of their cells that gives them shape and is a source of strength. Antibiotics like penicillin kill bacteria by preventing building of the wall, but the antibiotics that we found actually work by doing the opposite — they prevent the wall from being broken down. This is critical for cell to divide.
“In order for a cell to grow, it has to divide and expand. If you completely block the breakdown of the wall, it is like it is trapped in a prison, and can’t expand or grow.”
These new antibiotics come from the family known as glycopeptides, a group of anti-bacterial compounds found in soil. They are often used to treat Methicillin-resistant Staphylococcus aureus (MRSA). Corbomycin and complestatin have been shown to block infections in mice caused by MRSA, a promising advance in the fight against drug resistant bacteria.
“We hypothesised that if the genes that made these antibiotics were different, maybe the way they killed the bacteria was also different.
“This approach can be applied to other antibiotics and help us discover new ones with different mechanisms of action. We found one completely new antibiotic in this study, but since then, we’ve found a few others in the same family that have this same new mechanism” explained Culp.
While it is still early days, these are promising developments in the field of pathology and can provide important new tools in the fight against antibiotic resistant bacteria.