For the better part of a century, antibiotics have been the go-to method for wiping out bacterial infections. It works out pretty well until the bacteria — like any other pest — eventually begins to develop a resistance to the stuff that’s trying to kill it. Such bacterial resistance to antibiotics can stump medical professionals and turn otherwise treatable infections into dangerous killers (Pseudomonas aeruginosa, for example, is an antibiotic resistant strain of bacteria that, when infecting patients stricken with compromised immune systems from HIV, cancer, pneumonia, cystic fibrosis, urinary tract infections, and even injuries, boasts a 50 percent fatality rate). It’s hard for the pharmaceutical industry to keep up with the demand for new stuff that can kill these rascally antibiotic resistant bacteria when the old stuff fails. But what if there were a somewhat gentler approach? What if, instead of trying to eradicate antibiotic resistant bacteria, we were able to convince it to simply live and let live?
University of Wisconsin-Milwaukee professor of biological sciences Ching-Hong Yang and Xin Chen, a professor of chemistry at Changzhou University in China, have discovered a way to do just this; a compound can be introduced that turns off the part of the bacteria’s DNA that usually instructs it to infect a host — effectively reprogramming it to be harmless. It bypasses the sticky problem of antibiotic resistance while the outcome enjoyed by the host is effectively the same as it would be if traditional antibiotics happened to be successful: he/she gets to live!
Explains Yang: “We analyzed the genomic defense pathways in plants to identify all the precursors to infection,” says Yang. “Then we used the information to discover a group of novel small molecules that interrupt one channel in the intricate pathway system.”
It’s especially exciting that that this method of fighting (well, convincing, really) antibiotic resistant bacteria should theoretically work for plants, animals, and humans. The compound that the scientists have created targets the type III secretion system (T3SS) in invasive bacteria and diminishes their self-esteem by making them unrecognizable by their host. These bacteria are pretty stupid, right?
“These bacteria are very smart,” says Yang. “They grow a narrow appendage that acts as a ‘needle,’ injecting the virulence factors, such as toxins, into the host cell. The host cell cannot recognize the pathogen’s ‘needle,’ so its defense mechanism is not triggered.”
It’s almost as if the host cell is plugging its ears and shouting, “I’m not listening to you! I’m not listening to you!” (And unlike when you’ve tried it with your pesky little sister, this ploy actually works. Maybe bacteria aren’t as smart as Ching-Hong Yang would have us believe, hmm?)
“T3SS exists in many different kinds of disease-causing bacteria,” says Yang, “so the compounds can target multiple pathogens. That’s the beauty of it.”
The team’s findings have been published online in the recent edition of Antimicrobial Agents and Chemotherapy.