Escherichia coli-associated urinary tract infections (UTIs) are among the most common bacterial infections in humans. UTIs are usually managed with antibiotic therapy, but over the years, antibiotic-resistant strains of uropathogenic E. coli (UPEC) have emerged. The formation of biofilms further complicates the treatment of these infections by making them resistant to killing by the host immune system as well as by antibiotics. This has encouraged research into therapy using bacteriophages (phages) as a supplement or substitute for antibiotics. In this study we characterized 253 UPEC in terms of their biofilm-forming capabilities, serotype, and antimicrobial resistance. Three phages were then isolated (vB_EcoP_ACG-C91, vB_EcoM_ACG-C40 and vB_EcoS_ACG-M12) which were able to lyse 80.5% of a subset (42) of the UPEC strains able to form biofilms. Correlation was established between phage sensitivity and specific serotypes of the UPEC strains. The phages’ genome sequences were determined and resulted in classification of vB_EcoP_ACG-C91 as a SP6likevirus, vB_EcoM_ACG-C40 as a T4likevirus and vB_EcoS_ACG-M12 as T1likevirus. We assessed the ability of the three phages to eradicate the established biofilm of one of the UPEC strains used in the study. All phages significantly reduced the biofilm within 2–12 h of incubation.

Bacteriophages or “phages” are viruses of prokaryotes. At least 5,360 tailed and 179 cubic, filamentous, and pleomorphic bacterial viruses have been examined in the electron microscope since the introduction of negative staining in 1959. Since at least 100 novel bacterial viruses are described every year1, the approximate number of viruses under consideration is over 6,000. Numerically, this makes bacteriophages the largest virus group known. Phages are presently classified in a hierarchical and holistic system with one order and 10 families. Over 96% of phages are tailed and contain dsDNA. The seven families of cubic, filamentous and pleomorphic phages are small and well defined. They contain ds or ss DNA or RNA. The most important developments are reclassifications of the Podoviridae and Myoviridae families of tailed phages.