In Vitro Synergistic Inhibition and Eradication of Pathogenic Bacterial Biofilms by Bacillus subtilis-derived...

Biofilm formation is a crucial virulent attribute of pathogens that promotes their resistance to antibiotics and contributes to chronic illnesses in humans. Traditional antibiotic therapies have proven ineffective in eliminating sessile microbial populations within biofilms, necessitating the development of novel therapeutic strategies. In this study, the in vitro efficacy of the anti-biofilm enzymes derived from Bacillus subtilis was evaluated against biofilm-forming human clinical pathogens.

An in vitro impact of combined anti-biofilm enzymes obtained from Bacillus subtilis C5W on the inhibition and eradication of biofilms of A. baumannii, E. aerogenes, and E.coli was monitored using a spectrophotometric microtiter plate assay.

Among seven clinical pathogens, three pathogens were found to be strong biofilm producers as they formed biofilm at an incubation time of 48 hours. The anti-biofilm enzymes significantly inhibited the biofilm formation of A. baumannii and E. aerogenes at an incubation time of 48 hours, with inhibition rates of 62.51% and 57.91%, respectively. In contrast, the maximum inhibition of biofilm formation in E. coli was observed at 24 hours, with an inhibition rate of 76.69%. The biofilm eradication rates were recorded to be 30.17% (A. baumannii), 46.29% (E. aerogenes), and 53.02% (E. coli) after a 24-hour incubation time. The SEM images confirmed the disruption of adhered biofilm on the glass surface and aggregation of microcolonies.

The study highlighted that Bacillus subtilis-derived enzyme combinations showed a synergistic inhibitory effect against biofilms formed by human clinical pathogens under in vitro conditions. The combined enzymatic treatment not only disrupted established biofilms but also suppressed their formation, indicating an enhanced anti-biofilm potential.

These findings demonstrated the multi-enzyme approach as a promising and effective alternative to conventional antimicrobial approaches for managing biofilm-associated infections.