Researchers harness phages to combat drug-resistant bacteria with novel treatment methods 

Bacterial infections pose significant challenges to agriculture and medicine, especially as cases of antibiotic-resistant bacteria continue to rise. In response, scientists at Texas A&M AgriLife Research are elucidating the ways that bacteria-infecting viruses disarm these pathogens and ushering in the possibility of novel treatment methods.   

In their recent study published in Science, Dr. Junjie Zhang and Dr. Lanying Zeng, professors in the Texas A&M College of Agriculture and Life Sciences Department of Biochemistry and Biophysics, and four colleagues detailed a precise mechanism by which phages disable bacteria. 

Pseudomonas aeruginosa is a type of bacteria that can cause infections in the blood, lungs and occasionally other parts of the body. These infections are especially common in healthcare settings, which often encounter drug-resistant bacteria.  

The prevalence of antibiotic-resistant Pseudomonas infections makes them a practical focus for phage therapy, a type of treatment method using bacteriophages, or phages, to target and kill specific bacteria to treat infections.  

In their study, the researchers studied this process by using fluorescence microscopy, cryogenic-electron microscopy and computational modeling. They observed how a phage called PP7 infects P. aeruginosa by attaching to the pilus, structures that extend from the surface of bacteria, which then retracts and pulls the phage to the cell surface.  

At the point of entry for the virus, the pilus bends and snaps off, and the loss of the pilus makes P. aeruginosa much less capable of infecting its own host.  

The study on Pseudomonas is part of the researcher’s recent suite of studies. Last month, they published findings in Nature Communications on the interaction between another genus of bacteria, Acinetobacter, and a phage that infects it. Another study, expected to be published next month, will cover a third genus of bacteria and additional phage.   

The implications of this ongoing research could prove to be important in treating antimicrobial infections. Zhang said doctors wouldn’t need to use phages to kill the bacteria — as is done in phage therapy — but could simply allow the viruses to disarm the bacteria, which may give the immune system the chance to fight the infection on its own or allow doctors to treat patients with lower doses of antibiotics.