Isolation and identification of bacteriophage against Escherichia coli ATCC 25922 and their biofilm Inhibition studies

Bacterial biofilm development plays a crucial role in causing serious health concerns in the medical sector. The adhesion of germs on living and non-living surfaces can lead to damage as well as diseases in humans, and other animals. To address this problem, researchers focus exclusively on bacteriophage therapy. In the present study, lytic phage with 10¹⁰ PFU/mL was isolated from hospital sewage samples by targeting Escherichia coli (ATCC 25922). The morphological study of the isolated phage was examined under high-resolution transmission electron microscopy (HR-TEM) by using 2% of uranyl acetate as a negative staining, which revealed that the isolated phage belonged to the Myoviridae family. Bacterial turbidity assay showed reduced optical density (OD) in 0.01 multiplicity of infection (MOI) and no growth in 0.1 and 1.0 MOI phage concentration which was compared with control (without phage-treated E. coli cells). The phage-host interaction was investigated using an HR-TEM after treating the phage for 30 min, which showed the lytic cycle of the phage. Further, the E. coli biofilm was assessed using a microplate reader after 24 and 48 h on 96 titer plates with crystal violet staining to confirm the inhibition efficiency of phage-treated biofilm quantitatively (83%). Then the compound and fluorescence microscopy were used for qualitative measurement of inhibition activity. Further, the biofilm formation of E. coli on a coverslip surface was analysed using scanning electron microscopy, comparing samples treated with 0.1 MOI of phage to untreated controls. About 10% of countable cells only present over the phage-treated surface (90% of biofilm inhibition). The outcome of this study revealed that phage treatment effectively suppressed the E. coli biofilm development, and it can be used as a sustainable and eco-friendly approach for the control of biofilm formation on surfaces specifically in hospital environments.