P. MATHIVADANA*, G. SANGEETHA1 AND S. RAJYOGANANDH VIJAYARAMAN
Department of Microbiology, Vels Institute of Science Technology & Advanced Studies, Chennai-6000117 (Tamil Nadu), India
*(e-mail: vadana.prabhu@gmail.com; Mobile: 98404 02563)
(Received: April 15, 2024; Accepted: June 4, 2024)
ABSTRACT
This study aimed at isolating and characterizing multidrug-resistant Klebsiella pneumoniae and Staphylococcus aureus from sewage samples, and to investigate the stability and release kinetics of encapsulated bacteriophages targeting these pathogens. Sewage samples were collected, processed and subjected to serial dilution and bacterial isolation on selective media. Isolates were identified via gram staining, biochemical tests and 16S rRNA sequencing. The Kirby-Bauer disc diffusion method was employed to determine the antibiotic resistance profiles of the bacterial isolates, while the plaque assay method was used to quantify phage activity.Antibiotic sensitivity assays confirmed multidrug resistance in both bacteria. Bacteriophages were isolated from sewage and encapsulated using chitosan-alginate beads, with and without alum as an adjuvant. Encapsulated and non-encapsulated phage were tested for stability and release under simulated intestinal and thermal conditions. Results indicated that encapsulation significantly improved phage stability and controlled release, particularly in simulated intestinal environments. Encapsulation with alum further enhanced release kinetics. Thermal stability assays at 37 and 80°C showed variable phage stability, with encapsulated phage exhibiting better resilience compared to non-encapsulated ones. Statistical analyses (t-tests and ANOVA) confirmed significant differences in release behaviours between different encapsulation conditions. These findings suggest that the encapsulation, especially with adjuvant, enhances phage stability and release, offers a promising strategy for phage therapy applications targeting gastrointestinal infections. Further research into optimizing encapsulation methods could improve the therapeutic efficacy of bacteriophage treatments.
Key words: Bacteriophages, encapsulation, chitosan-alginate, stability, release kinetics, antibiotic resistance, Klebsiella pneumoniae, Staphylococcus aureus