Establishment of a Bacteriophages Platform: Alternative Therapeutic Option

Abstract

Background: Pathogenic Escherichia coli, common water contaminant, cause a large number of morbidity and mortality worldwide. Unfortunately, unrestricted use of antibiotics led to the appearance and spread of antibiotic resistant isolates. Regardless of the numerous efforts to overcome antibiotic resistance, this threat to public health is but only increasing. This stresses the need for an alternative therapeutic modality for antibiotics such as bacteriophages. Bacteriophages are bacteria-killing viruses; lytic bacteriophages are one type of phage that drives the direct targeted killing of bacteria. Unlike lysogenic phages that possess an integrase gene, lytic phages do not. The integrase gene gives phages the ability to incorporate their genetic material into the host genome, thus allowing them to remain dormant in the host. Bacteriophage therapy relies on the use of lytic phages as it aims to treat infections as quickly and effectively as possible. Therefore, we decided to isolate phages against E. coli ATCC 25922 from Ain El-Mreiseh and Ramlet El-Bayda sewage samples. Methods: In the current study, two sewage samples were collected from Ain El-Mreiseh and Ramlet El-Bayda sewage sources. Isolation of phage was done by Double Agar Layer Assay method using E. coli ATCC 25922 as host strain. Moreover, phages were characterized on the basis of host range, latent period, burst size, bacteriolytic activity, and biofilm inhibition and elimination capability. Results: Seven distinct phages were isolated against E. coli ATCC 25922 from Ain ElMreiseh and Ramlet El-Bayda sewage samples. Mean phage titer of above seven phage isolates ranged between 1010 and 1015 Plaque Forming Units/ml. AM 02 recorded the widest host range followed by AM 01 while AM 03, AM 04, RB 01, RB 02, and RB 03 displayed the lowest host range. RB 03 was found to have the shortest latent period and the smallest burst size. In addition, all 7 phages showed considerable bacterial killing effect, and a potential role in preventing E. coli ATCC 25922 biofilm formation; and the phages AM 03, AM 04, RB 01, RB 02, and RB 03 were able to significantly eliminate mature biofilm. Conclusion: We successfully isolated and characterized seven bacteriophages. Several phages are potential candidates to be included in our phage library giving there promising bacterial killing effect, and ability in biofilm prevention and elimination.