This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: The bacterium Acinetobacter baumannii poses a substantial threat in health care settings, readily forming biofilms on wounds and medical surfaces and 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) 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 cows' diets. The work is published in npj Biofilms and Microbiomes.
"Polysaccharides are one of the major components [of bacterial biofilms], constituting 45% to 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 Ph.D. student in IPC and first author of the study. A specific enzyme that the team named CRhAB (Cow rumen hydrolase against A. baumannii) was highly effective against the bacterium's biofilms as well as those of 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 pathogens in the ESKAPE 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.
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