Bacterial biofilms, highly resistant to the conventional antimicrobial therapy, remain an unresolved challenge pressing the medical community to investigate new and alternative strategies to fight chronic implant-associated infections. Recently, strictly lytic bacteriophages have been revalued as powerful agents to kill antibiotic-resistant bacteria even in biofilm. Here, the interaction of T3 bacteriophage and planktonic and biofilm Escherichia coli TG1, respectively, was evaluated using isothermal microcalorimetry. Microcalorimetry is a non-invasive and highly sensitive technique measuring growth-related heat production of microorganisms in real-time. Planktonic and biofilm E. coli TG1 were exposed to different titers of T3 bacteriophage, ranging from 102 to 107 PFU/ml. The incubation of T3 with E. coli TG1 showed a strong inhibition of heat production both in planktonic and biofilm already at lower bacteriophage titers (103 PFU/ml). This method could be used to screen and evaluate the antimicrobial potential of different bacteriophages, alone and in combination with antibiotics in order to improve the treatment success of biofilm-associated infections.
Keywords: Antimicrobials; Bacterial biofilm; Calorimetry; Lytic activity; Phage therapy; Phage-host interplay.
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