P. MATHIVADANA*, G. SANGEETHA AND RAJYOGANANDH S. VIJAYARAMAN
Department of Microbiology, Vels Institute of Science Technology & Advanced Studies, Chennai-600 117 (Tamil Nadu), India
*(e-mail: vadana.prabhu@gmail.com; Mobile: 98404 02563)
(Received: December 11, 2024; Accepted: January 21, 2025)
ABSTRACT
The emergence of multidrug-resistant (MDR) bacteria, such as Escherichia coli, necessitates alternative strategies to combat infections. This study focused on the isolation, characterization and encapsulation of bacteriophages targeting MDR E. coli. Bacteriophages were isolated from sewage water, purified using plaque assays and stored for subsequent analyses. MDR E. coli isolates were obtained from sewage samples and confirmed using biochemical test. Antibiotic sensitivity testing revealed resistance to multiple antibiotics including amoxicillin and ciprofloxacin, underscoring the critical need for non- antibiotic treatment options. Phages were encapsulated using sodium alginate and chitosan, with and without adjuvants to enhance stability and delivery under harsh conditions. Stability assays demonstrated that encapsulation significantly improved phage survival in acidic, thermal and simulated intestinal conditions, with the addition of an adjuvant by further enhancing stability and release. Lytic activity assays revealed that encapsulated phages, particularly with adjuvants effectively inhibited MDR E. coli growth over 24 h, showing significant improvements compared to non-encapsulated counterparts. Statistical analysis confirmed the superiority of encapsulated phage formulations in stability and efficacy. These findings highlight the potential of encapsulated bacteriophages as a robust alternative to antibiotics for combating MDR pathogens. The study emphasized the importance of environmental sources for discovering effective phages and laid the groundwork for developing phage-based therapies in clinical and environmental applications.
Key words: Bacteriophages, encapsulation, chitosan-alginate, stability, release kinetics, simulated intestinal juice, antibiotic resistance, Escherichia coli, lytic activity