Isolation and characterization of two novel phages as a possible therapeutic alternative against multi-drug resistant E. coli

Escherichia coli is one of the most common pathogens around the world, causing a wide range of infections. Most strains are multidrug resistant to antimicrobial therapy, leading to therapeutic options limitation. Because of increasing numbers of antibiotic resistance bacteria and lack of efficient control methods for multidrug resistant bacteria dissemination, phages are one of the promising alternatives that target bacteria specifically and effectively. Their highly specific host ranges and ability to kill only the target pathogenic bacteria selectively characterize phages. However, several challenges and limitations in phage therapy regarding management of multidrug resistant bacteria require more investigation. In this study, two novel lytic phages referred to as AAA1 and AAA2 were isolated from the Tigris River, Baghdad, IRAQ, characterized for their lytic efficiency, functional stability and characteristics against multidrug resistant E. coli host. Phage AAA1 lysed drug resistant E. coli whereas AAA2 showed no lytic activity. The two phages were stable in the temperature range of 4 degrees C to 37 degrees C. The tolerance of AAA1 phage to pH level was higher than AAA2. The AAA1 phage is a promising candidate to treat or control multi-drug resistant (MDR) E. coli strains.