Researchers at the University of Medicine and Dentistry of New Jersey have identified two predator microbes that can kill off dangerous bacteria that cause eye infections resistant to antibiotics.

The findings, published in the journal PLoS ONE, highlight how effective bacteria can be used to fight off infections.

Two antibiotic-resistant ocular pathogens (bad bacteria), Pseudomonas aeruginosa and Serratia marcescens, were found to be susceptible to good, non-infectious bacteria called Micavibrio aeruginosavorusand Bdellovibrio baceriovorus.

In order to find out whether M. aeruginosavorus and B. baceriovorus could be used to fight off eye infections and not damage the human eye, the researchers exposed them to human corneal-limbic epithelial cells. They found that the good predator bacteria didn’t cause any inflammation or toxicity in those cells.

The scientists then injected the good bacteria into a species of worm called Galleria mellonella, which has always served as a good model when examining the toxicity of microbes.

When the worms were injected with the pathogen P. aeruginosa all of them died, however, when they were injected with the two good predator microbes they had an 11-day survival rate of between 93 to 100 percent.

This means that the “good” bacteria were not toxic to the worms and didn’t provoke any aggressive immune responses.

The lead author of the study, Daniel Kadouri, PhD, an assistant professor of oral biology at the University of Medicine and Dentistry of New Jersey – New Jersey Dental School, said:

“Taken together, our findings leave us confident that, in isolation, pathogenic bacteria are susceptible to successful attack by predator bacteria, predator bacteria do not appear inherently harmful to ocular cells when applied topically, and a live organism can tolerate the predator bacteria well.

The time to test all three phenomena simultaneously in the eye tissue of a live organism may now be at hand.”

A previous study, also published in PLoS ONE, similarly used “good” bacteria to fight off 12 strains of dangerous multi-drug resistant (MDR) bacteria.

The results revealed that the MDR strains which are resistant to all current antibiotics have no defenses against the good predator bacteria.

In conclusion, these findings suggest that predatory bacteria could be used to kill off MDR bacteria where conventional therapy has failed to work. It is still uncertain whether the good bacteria will have the same effect on MDR in the human body as in the lab. However, Kadouri’s research is very promising.

Mark Spigelman, professor at the Hebrew University of Jerusalem’s Faculty of Medicine, previously stressed that antiseptics and antibiotics in hospitals are actually putting patients at a greater risk of suffering fatal bacterial infections that are resistant to medication.

They believe that it would be good to allow the harmless or “good” bacteria to live in the hospital environment, creating a kind of natural protection against the deadlier strains.

Another major finding which could help treat drug resistant infections was published in the online edition of the Proceedings of the National Academy of Sciences. Researchers in the US found a way to target and kill antibiotic resistant bacteria using Bisphosphates, which are already approved as a treatment for bone loss.

Written by Joseph Nordqvist