The bacterium Acinetobacter baumannii poses a substantial threat in healthcare settings, readily forming biofilms on wounds and medical surfaces, contributing to persistent infections and delayed healing. Its growing antimicrobial resistance (AMR) and status as a WHO critical priority pathogen underscore the urgent need for new wound management strategies. However, many current treatments are ineffective against its biofilms.
Biofilms are communities of bacteria encased in a matrix made up largely of polysaccharides, proteins, lipids, and extracellular DNA. They form a physical barrier that reduces the penetration and efficacy of antimicrobials and host immune cells.
In a new study, researchers at the Indian Institute of Science (IISc) have identified specific enzymes from bovine rumen (cow gut) that can break down the polysaccharide components of these biofilms. They used genomic data from rumen microbes to identify enzymes capable of digesting cellulose – a polysaccharide also abundant in the cow diet.
“Polysaccharides are one of the major components [of bacterial biofilms], constituting between 45% and 95%,” says Debasis Das, Associate Professor at the Department of Inorganic and Physical Chemistry (IPC), IISc and co-corresponding author. These polysaccharides enhance biofilm strength and structural stability by cross-linking with each other.
“Matrix inhibition or disruption makes A. baumannii more vulnerable. Instead of directly killing the bacteria, it weakens their defenses, potentially restoring the effectiveness of existing antibiotics while reducing the selective pressure that drives antibiotic resistance,” adds Reshma Ramakrishnan, former PhD student in IPC and first author of the study.
A specific enzyme that the team has named CRhAB (Cow rumen hydrolase against A. baumannii ) was highly effective against the bacterium’s biofilms as well as those of the bacterium Klebsiella pneumoniae . The enzyme drastically reduced biofilm formation and substantially suppressed the expression of key biofilm-related genes in the bacteria.
“Both A. baumannii and K. pneumoniae are among the most notorious of the ESKAPE pathogen group, and thankfully, this enzyme acts against both. It’s a dual bacterial strategy with one enzyme,” says Dipshikha Chakravortty, Professor at the Department of Microbiology and Cell Biology (MCB), IISc, and co-corresponding author. This dual activity is particularly important because well-developed biofilms are highly resistant to antibiotics and are a major cause of persistent infections.
To manage wound infections, the team also developed a gauze with the enzyme imbibed in it. A key challenge was establishing a reliable mouse wound infection model, says Ramakrishnan. “Maintaining the enzyme-immobilised gauze over the wound throughout the study was particularly difficult because the mice naturally tried to remove the dressing. We had to optimise the experimental setup to ensure that the gauze remained in place while minimising stress to the animals,” she explains.
The researchers are also working on a patch-like wound dressing to treat challenging infections such as diabetic foot infections. In addition, they are investigating delivery systems for respiratory infections, including those caused by K. pneumoniae , and the possibility of combining multiple enzymes to target a broader range of pathogenic biofilms.
“A long-term goal is to develop an inhalable or nebulisable CRhAB formulation that delivers the enzyme directly to the lungs, thereby preventing biofilm formation and disrupting established biofilms. Such a localised, non-invasive approach could offer a promising new treatment for chronic A. baumannii respiratory infections,” Ramakrishnan adds.
npj Biofilms and Microbiomes
A matrix-targeting enzyme and an engineered bioactive gauze enable resistance-agnostic antibiofilm wound care
31-Jul-2026