Bacterial infections, including so-called superbugs, or antibiotic-resistant bacteria, may ultimately be addressed by viruses, or at least that’s the hope indicated by a study recently published in the journal Nature. It may sound like the plot of a cartoon or video game, but researchers at Tufts University School of Medicine found the first evidence that bacteriophages can “hijack” the host bacteria’s immune system and use it to destroy that host. Bacteriophages (or phages, for short) are viruses that prey on specific bacteria. The study followed a phage that is a viral predator of Vibrio cholera, the bacterium that causes human cholera epidemics, and verified the results by infecting the same strain of cholera bacteria with phage that lacked the adaptive immune system.
Most bacteria are vulnerable to phages, and have immune mechanisms to protect themselves. About half of known bacteria use an adaptive system, CRISPR/Cas (Clustered Regularly Interspaced Short Palindromic Repeats) that can rapidly respond to a wide variety of attacks. Phages were previously believed to be primitive DNA or RNA particles. This is the first evidence that something as complex as an adaptive immune system can be transferred from a bacteria to a virus. Once it’s transferred, that immune system adapts and turns on its former owner, and then the virus can replicate and destroy more bacteria.
With this knowledge, phage therapy, using phages to treat bacterial diseases, moves a little closer to becoming a reality. The research team is currently studying the mechanism by which the phage immune system disables the cholera bacteria’s defenses, a step towards the design of a phage therapy for cholera in humans. Hopefully, phage therapy for other superbugs will follow.
Holding out such hope is especially important in light of the recent report from the Centers for Disease Control and Prevention about the rise of carbapenem-resistant Enterobacteriaceae (CRE). Those CRE germs are resistant to nearly all current antibiotics, and what’s worse, are able to spread that resistance to other bacteria.
Until phages or other solutions are available, a multifaceted approach to getting superbugs under control is essential. We have to focus on reducing the risk of infection in addition to detecting and treating existing infections. Superior environmental hygiene practices are a critical part of that process, but are often dependent upon the vagaries of human behavior. While proper hand hygiene is the keystone of effective infection prevention systems, compliance is always lacking. So, healthcare leaders need to adopt technologies that continuously reduce bioburden on hospital surfaces around the clock – independent of human intervention.