Fig 1.
Schematic representation of the overall method from sample processing up to phage purification.
Table 1.
Summary of phages isolated against TASP18 and TASP92 using spot assay.
Table 2.
Summary of phages isolated against TASP18 and TASP92 using plaque assay.
Table 3.
The titer of isolated phages.
Table 4.
Host range analysis result of selected eight phages.
Fig 2.
Representative images during spot isolation.
Fig 3.
Illustrative images showing quality control results for experimental conditions.
“A” Filtrate control: no growth was observed on the media spotted with sample filtrate prepared without host bacteria, indicating that the filtered samples were free from bacterial contamination confirming that the filtration process was sufficient and that any observed effects in experimental samples can be attributed to the phages. “B” Media control: no growth was observed on the bottom agar lawn with soft agar, confirming the sterility of the media used in the experiments. This suggests that the growth of bacteria in the experimental plate can be attributed to the host lawn. “C” Host control: there was no lysis in the host control, which was made up of soft agar with bottom agar and host bacteria validating the lack of lytic activity from any contaminants, making certain that any lysis seen in test samples is exclusively related to the samples being examined. “D/E” Experimental results: showing growth of host bacteria and presence of lytic phages against the tested host.
Fig 4.
Illustrative images during host range analysis.
“A” Lysis zones observed on K. pneumoniae ®ATCC 700603 during host range assessment by spot assay by four phages. The labeling written on the plate as A, B, C, and D indicates the replica spot of the corresponding phage.
Fig 5.
Phage efficiency against various bacterial strains.
EOP values were categorized as Low productive (0.001 < EOP < 0.1), medium productive 0.1 < EOP < 0.1), highly productive (EOP ≥ 0.5), and inefficient (≤0.001) a value 1 indicates isolation host. The red color in the heat map indicates “NA” not applicable; indicating the phage did not lyse the corresponding bacteria.
Fig 6.
Illustrative images during EOP.
Plaque of phage GKMs-TASP18 on K. pneumoniae ®ATCC 700603 during EOP. Optimum Multiplicity of infection (MOI) of selected phages.
Table 5.
Optimal multiplicity of infection of eight phages.
Fig 7.
Single-step growth curve experiment of isolated phages.
The data points represent the average Log (PFU/mL) at each incubation time, with standard deviation (SD) indicated by vertical lines on the Y-axis. The data were analyzed using a one-way ANOVA followed by Tukey’s HSD test (***P < 0.0059).
Fig 8.
Phage stability under different pH gradients.
The bar represents the titer of eight phages at five different pH values 3, 5, 7, 9, and 11. The data point indicates the mean titer in PFU/mL. SD is indicated using vertical lines on the Y-axis. The data were analyzed using a one-way ANOVA, followed by Tukey’s HSD test (**P < 0.003).
Fig 9.
Phage viability across a temperature gradient.
The data points represent the average titer. Standard deviation is indicated using vertical lines on the Y-axis. The data were analyzed using a one-way ANOVA, followed by Tukey’s post hoc test (**P < 0.04).