Year: 2025
Type: article
Abstract: Objectives Pseudomonas aeruginosa is a highly adaptive, nosocomial, and multi-drug-resistant opportunistic bacterium known for the production of extracellular polymeric substances (EPS). The presence of EPS hinders the penetration of antibiotics and other antimicrobial agents and thus poses a significant challenge in healthcare. The interaction between phages and the EPS of P. aeruginosa in terms of carbohydrate hydrolysis and structural changes were studied to assess the potential of phages to overcome the barrier of the EPS. Material and Methods Twenty-six P. aeruginosa isolates, including 18 multidrug-resistant clinical isolates and 8 drug-sensitive environmental isolates, were tested for sensitivity to a panel of 18 non-redundant phage lysates. EPS was extracted from each bacterial culture, and the total carbohydrate content was assayed before and after phage treatment using the phenol-sulfuric acid method. The effect of candidate phage activity on the structure of the EPS was further analysed using Fourier transform infrared spectroscopy (FTIR), comparing EPS that were treated with phages for different time intervals with untreated controls. The combinatorial effect of phages that degraded EPS but could not lyse the host cell, with cell wall and cell membrane targeting antibiotics, was determined. Results Of the 468 phage-host combinations tested, 380 (80%) exhibited host cell lysis, indicating phage sensitivity. However, only 30% of these phage-sensitive instances showed phage-mediated hydrolysis of the extracted EPS. However, it was interesting to note that phage-mediated EPS hydrolysis was observed in 40% of instances where the cultures were resistant to lysis due to phage infection. Phages that do not lyse the bacteria but degrade the EPS are effective in facilitating cell envelope-targeting antibiotics to lyse the bacterial pathogen. Conclusion This study highlights the effectiveness of bacteriophage in overcoming the hurdle of the exopolysaccharides in Pseudomonas aeruginosa in antimicrobial therapy.
Institution: Nitte University
Language: English
Subfield: Ecology
Field: Environmental Science
Domain: Physical Sciences
Open Access status: hybrid
OpenAlex ID: W4411368140