RESUMEN
Urinary tract infections (UTIs) are mainly caused by uropathogenic Escherichia coli (UPEC), whose impact can be exacerbated by multidrug-resistant (MDR) strains. Effective control strategies are, therefore, urgently needed. Among them, phage therapy represents a suitable alternative. Here, we describe the isolation and characterization of novel phages from wastewater samples, as well as their lytic activity against biofilm and adherence of UPEC to HEp-2 cells. The results demonstrated that phage vB_EcoM-phiEc1 (ÏEc1) belongs to Myoviridae family, whereas vB_EcoS-phiEc3 (ÏEc3) and vB_EcoS-phiEc4 (ÏEc4) belong to Siphoviridae family. Phages showed lytic activity against UPEC and gut commensal strains. Phage ÏEc1 lysed UPEC serogroups, whereas phages ÏEc3 and ÏEc4 lysed only UTI strains with higher prevalence toward the O25 serogroup. Moreover, phages ÏEc1 and ÏEc3 decreased both biofilm formation and adherence, whereas ÏEc4 was able to decrease adherence but not biofilm formation. In conclusion, these novel phages showed the ability to decrease biofilm and bacterial adherence, making them promising candidates for effective adjuvant treatment against UTIs caused by MDR UPEC strains. KEY POINTS: Phage with lytic activity against MDR UPEC strains were isolated and characterized under in vitro conditions. A novel method was proposed to evaluate phage activity against bacterial adherence in HEp-2 cell.. Phages represent a suitable strategy to control infections caused by MDR bacteria.