A 'library' of bacteria-killing viruses: Harnessing the power of phages

The human body hosts an estimated 38 trillion bacteria, most of which are harmless, though some can cause illness, particularly when they develop antibiotic resistance. To combat these drug-resistant infections, researchers are turning to bacteriophages, viruses that specifically target bacteria. A team of scientists at the University of Colorado Anschutz School of Medicine has been compiling a library of phages for over a decade, focusing on strains that inhabit the intestines.

Phages have been used for decades to help understand molecular biology, but their potential for treating antibiotic-resistant infections has sparked renewed interest. Unlike human cells, bacteria can be infected by viruses, which contain genetic material and can use host cells to reproduce. Once inside a bacterial cell, a phage can disrupt its function and potentially kill the cell.

To develop their phage library, researchers collect bacteria from untreated wastewater, which contains various bacteria, including those that make up the gut microbiome. They then expose these bacteria to the wastewater and grow them on agar plates, creating a "bacterial lawn." By extracting phages from the round plaques that form within this lawn, they can purify the phage samples and store them for future use.

The team currently has over 30 phages that infect enterococcal bacteria and around 15 to 20 that target Enterobacter and Klebsiella. These phages can be combined with existing antibiotics or delivered orally or intravenously. While phages aren't a universal cure, they offer a promising alternative when standard antibiotics fail.

However, bacteria can develop resistance to phages, just as they can to antibiotics. Despite this, the researchers believe that continued exploration of phage biology will lead to valuable insights about our natural world and the role of phages in maintaining health.