Hybrid antibiotics punch through bacterial biofilms

On their own, bacteria aren’t too hard to kill. The problem is, the crafty bugs tend to build colonies behind barriers known as biofilms, which are hard for antibiotics to penetrate. Now, researchers at the Queensland University of Technology (QUT) have developed a hybrid antibiotic that can punch through some biofilms.

Biofilms pose a particular problem in places exposed to bacteria for extended periods, including medical tools like catheters or implants. That makes it harder for drugs or antibacterial chemicals to break through and do their job, leading to antibiotic resistance and possibly recurring infections. But the researchers on the current study say they’ve developed a new method to bust the door down.

“Biofilms are a sticky, slimy coating that often prevents conventional antibiotics from accessing bacterial cells,” says Anthony Verderosa, co-lead author of the study. “We have developed a new breed of antibiotic that tricks biofilms into releasing their protected cells allowing access through the protective slimy coating of the biofilm. This allows for the biofilms to be eradicated.”

This “new breed” is a combination of a widely-used antibiotic known as ciprofloxacin, along with compounds called nitroxides. The latter were recently found to be effective at blasting away biofilms, letting the ciprofloxacin get in and kill off the bacteria.

The team tested the mix on biofilms made by golden staph (Staphylococcus aureus) bacteria. The antibiotic hybrids were found to effectively penetrate the biofilms and eradicate the bacteria, and better yet, it took a smaller amount of ciprofloxacin than usual to do the job. They saw no sign of toxicity to healthy human cells either.