Superbugs set to meet their match

McMaster researchers find drug combo that might tackle antibiotic-resistant infections

McMaster University researchers believe they have discovered a combination of drugs that can be used to treat antibiotic-resistant superbugs.

When used with other antibiotics, antifungal medication Pentamidine appears to be able to tackle drug-resistant infections, including two recently named the most “critical” priorities by the World Health Organization (WHO) — Acinetobacter baumannii and Enterobacteriaceae.

The possible breakthrough was published Monday in the journal Nature Microbiology.

“Infections by these organisms are just simply infections where there are sometimes no alternatives,” said Dr. Eric Brown, senior author of the paper and a scientist at the Michael G. DeGroote Institute for Infectious Disease Research.

“This is potentially a therapy of very last resort and, at the very least, perhaps another alternative … for the worst and most stubborn of infections.”

Brown’s research team focused on targeting Gram-negative bacteria — bugs that are the most difficult to treat because their tough outer shells are impenetrable by antibiotics, including “last-resort drugs” like colistin.

This type of bacteria can lead to pneumonia, blood infections and meningitis, infections that can be deadly, particularly in hospital settings, he said.

“These are sick patients,” Brown said. “We’re really looking at the most difficult to treat and grievous medical conditions, as far as infection goes.”

Using combination therapy, researchers were able to “open a door” on the surface of the bacteria to let antibiotics in, he said.

This is significant because there are no drugs that target the outer shell of this type of bacteria to treat the infections they can cause, Brown said.

For three to four years, the project in Brown’s lab has involved testing on mice.

Next steps for the researchers include seeing if they can find a way to make the combo therapy more effective on the WHO’s third most “critical” priority — Pseudomonas aeruginosa, another type of Gram-negative bacteria — and working to offset potential side effects of the drug.

As for testing in humans, Brown said that’s not really his “forte,” but the researchers would be happy to work with an infectious disease clinician interested in doing a clinical trial to see if their combination therapy works.

Because Pentamidine already exists in hospitals, “it’s conceivable that a gutsy infectious disease clinician could prescribe it off-label,” he added.

The study was funded by grants from organizations including the Canadian Institutes of Health Research, the National Sciences and Engineering Research Council and Cystic Fibrosis Canada.

Perhaps another alternative ... for the worst and most stubborn of infections. DR. ERIC BROWN SCIENTIST AT MICHAEL G. DEGROOTE INSITUTE FOR INFECTIOUS DISEASE RESEARCH