We’ve already been warned: By 2050, the rise of superbugs — those evolved strains of bacteria that have developed resistance to our most powerful antibiotic drugs — can potentially result in 10 million human fatalities, if we are unable to do anything to curb the worsening threat. Fortunately, it looks like the tide may soon turn in our favor as scientists may have discovered a way to make a superbug turn back into a regular bug, one that we can defend ourselves against.
According to Oregon State University researchers led by Bruce Geller, they have developed a molecule that can neutralize bacteria’s resistance to antibiotics. It’s called peptide-conjugated phosphorodiamidate morpholino oligomer — PPMO for short — and it has demonstrated the ability to prevent the expression of an enzyme known as New Delhi Metallo-beta-lactamase — or NDM-1 — the culprit that turns ordinary bacteria into superbugs.
As the team explained, many commonly used antibiotics have now been rendered useless because everything is already resistant to them. This prompted efforts to develop new and more powerful drugs, but this proved futile. And so a different strategy was used — modifications on existing antibiotics was done instead. This however, made the situation worse because the bugs simply mutated, which consequently made them resistant to the chemically modified antibiotics. This then paved the way for the invention of carbapenems, supposedly the strongest and most advanced penicillin drugs, also referred to as the ‘last resort drugs’.
To cut a long story short, NDM-1 is a serious problem because it makes bacteria resistant to carbapenems. In other words, if carbapenems won’t work, then nothing will. And that is exactly the predicament we are in, but one we hope is about to change.
In vitro, the research team was able to show that the modified PPMO restored the ability of meropenem — a drug of the carbapenem class — to fight three different strains of NDM-1 expressing bacteria. Moreover, the team was able to treat mice infected with NDM-1 positive E. coli bacteria by using a combination of PPMO and meropenem.
The results suggest that by combining PPMO with other existing antibiotics, it might be possible to make bacteria become vulnerable once again.
As Geller said, “A PPMO can restore susceptibility to antibiotics that have already been approved, so we can get a PPMO approved and then go back and use these antibiotics that had become useless.”
While tests on mice have been successful, there’s no reason to think (yet) that testing on humans will yield the same positive result. The team is quite conservative with their expectations, saying that they ‘might’ be ready for clinical trials in about three years. We just hope though they will be able to come up with positive results sooner rather than later.
The results of the study have been published in the Journal of Antimicrobial Chemotherapy.