Journal: Scientific Reports
Article Title: Isolation, functional characterization and antibiofilm properties of a lytic Enterococcus phage RG1 against multidrug resistant E. faecium
doi: 10.1038/s41598-025-21701-3
Figure Lengend Snippet: Antibacterial and antibiofilm activity of the phage RG1 against E. faecium ATCC 35667. ( A ) Antibacterial activity of the phage RG1 was monitored by studying growth kinetics of E. faecium without and with bacteriophage at different MOIs (0.01, 0.1, 1, and 10). The optical density (600 nm) was measured at every 20 min up to 4 h in a sterile microtiter plate at 37 ℃. Three technical replicates were used to calculate Mean ± SD, and plotted. ( B ) Growth rate (% per hour) at each MOI was calculated from the data of Fig. A using formula (Nt = N0 * (1 + r)t) where Nt is absorbance at time t, N0 is absorbance at start of the growth, r is growth rate, and t is time passed. ( C ) Bacteriophage was co-incubated (CI) for 24 h with host bacterium as well as post-infected (PI) for 2 h and 4 h on pre-existing 24 h old biofilm at MOIs of 0.1 and 1. Antibiofilm activity of the phage RG1 against E. faecium was investigated using the crystal violet assay as described in the method. Four technical replicates were taken to calculate Mean ± SD, and analysed by t -test using GraphPad Prism (version 5.01). The p values less than 0.05, 0.01 and 0.001 were indicated as (*), (**) and (***), respectively.
Article Snippet: Fig. 1 Isolation and characterization of the phage RG1. ( A ) Formation of plaques with a diameter of 2.1 ± 0.3 mm on Enterococcus faecium ATCC 35667 lawn by the phage RG1 using the double agar method. ( B ) Host Range analysis of phage RG1 against (a) E. faecium ATCC 35667 (b) E. faecalis (c) Pseudomonas aeruginosa (d) Klebsiella oxytoca (e) Burkholderia cepacia (f) Deinococcus radiodurans (g) Proteus mirabilis (h) Staphylococcus aureus. ( C ) Transmission Electron Microscopy-based morphological analysis of the phage RG1 showing an icosahedral head with a diameter of 53.96 ± 1.56 nm and a non-contractile tail with a length of 196.0 ± 6.86 nm. ( D ) Effect of different temperatures (for 1 h), ( E ) pH (for 1 h) and ( F ) chloroform concentrations (for 10 min) on the stability and viability of the phage RG1 was measured using 0.1 ml of ~ 10 8 PFU/ml of phage in double agar method.
Techniques: Activity Assay, Sterility, Incubation, Infection, Crystal Violet Assay