A Method to Determine the Efficacy of a Commercial Phage Preparation against Uropathogens in Urine and Artificial Urine Determined by Isothermal Microcalorimetry

Abstract

Background: Urinary tract infections are commonly encountered and often treated with antibiotics. However, the inappropriate use of the latter has led to the appearance of resistant strains. In this context we investigate the use of calorimetry to rapidly determine if a phage cocktail can be used as alternative to antibiotics. Methods: We used a commercially available phage cocktail from an online pharmacy and tested it against a strain of Escherichia coli and a strain of Proteus mirabilis. We used isothermal microcalorimetry to follow the metabolic activity of the bacterial culture treated with the phage cocktail. Results: Isothermal microcalorimetry was able to follow the dynamic of the bacterial metabolic activity reduction by the phage cocktail. Both pathogens were strongly inhibited; however, some regrowth was observed for E. coli in urine. Conclusions: Isothermal microcalorimetry proved to be a valuable technique when investigating the efficacy of phage cocktails against uropathogens. We foresee that isothermal microcalorimetry could be used to obtain rapid phagograms.

Microcalorimetry: A Novel Application to Measure In Vitro Phage Susceptibility of Staphylococcus aureus in Human Serum

“…In the future, MC could be used to determine phage susceptibility in other media resembling in vivo environments. For example, it has already been shown to be a valuable tool for phage susceptibility determination in urine [ 61 ]. MC might even lead to a novel form of personalized therapy, in which both the infectious strain and the bodily fluids of a patient can be used for bacteriophage selection.…”

“…Microcalorimetry (MC) is used to determine the metabolic activity of bacteria which is depicted as heat flow (in µWatt) over time and can be used as a proxy for bacterial growth [ 61 ]. In contrary to the optical density assay, MC is not affected by aggregation of S. aureus in serum.…”

Biothermodynamics of Viruses from Absolute Zero (1950) To – Virothermodynamics (2022)

“…Finally, reaction calorimetry or isothermal microcalorimetry measures heat released or absorbed during a chemical reaction, usually at constant temperature (without titration like in ITC) [Privalov, 2012;Sarge et al, 2014]. Reaction calorimetry has been applied to study virus multiplication inside host cells [Sigg et al, 2022;Tkhilaishvili et al, 2018a;Guosheng et al, 2003;Morais et al, 2014], phage action against bacterial biofilms [Tkhilaishvili et al, 2020a[Tkhilaishvili et al, , 2020b[Tkhilaishvili et al, , 2018a[Tkhilaishvili et al, , 2018b[Tkhilaishvili et al, , 2018cWang et al, 2020aWang et al, , 2020b, phage-bacteria interactions [Fanaei Pirlar et al, 2022;Wang et al, 2020c], phage transition from lytic into lysogenic cycles [Maskow et al, 2010b], antiviral therapy [Shadrick et al, 2013;Tkhilaishvili, 2022;Gelman et al, 2021], and influence on marine ecosystem metabolism [Djamali et al, 2012]. Thermodynamic properties of viruses can be calculated using biothermodynamic methodology.…”

The SARS-CoV-2 Hydra, a tiny monster from the 21st century: Thermodynamics of the BA.5.2 and BF.7 variants

“…Reaction calorimetry (isothermal microcalorimetry) has been applied to study virus multiplication inside host cells [ Sigg et al, 2022 ; Tkhilaishvili et al, 2018a ; Guosheng et al, 2003 ; Morais et al, 2014 ], phage action against bacterial biofilms [ Tkhilaishvili et al, 2020a , 2020 b, 2018 a, 2018 b, 2018 c; Wang et al, 2020a , 2020 b], phage-bacteria interactions [ Fanaei Pirlar et al, 2022 ; Wang et al, 2020c ], phage transition from lytic into lysogenic cycles [Maskow et al, 2010] , antiviral therapy [ Shadrick et al, 2013 ; Tkhilaishvili, 2022 ; Gelman et al, 2021 ], and influence on marine ecosystem metabolism [Djamali et al, 2012] .…”