Isolation and characterization of lytic bacteriophage against Extensively-Drug Resistant (XDR) Escherichia coli

Background and Aim : According to the reports of World Health Organization, increased use of antibiotics and bacterial resistance has become a global problem. Using alternative methods instead of antibiotic therapy would help to solve this problem. Phage therapy can be an appropriate method because the phages are completely safe and do not damage eukaryotic cells. The aims of this study were the isolation and characterization of specific bacteriophage against Extensively-Drug Resistant (XDR) Escherichia coli.Methods : Thirty-one XDR E. coli isolates collected from Vali-Asr hospital, Arak, Iran. A lytic phage against E. coli was isolated by standard method and its host range (against ۳۱ XDR E. coli, and some strains of Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii, Lactococcus lactis) as well as its thermal and pH stability in ۴۰-۸۰oC and pH ۱-۱۲ were determined.Results : Of ۳۱ E. coli isolates, ۲۰ isolates (۶۴.۵%) were lysed by bacteriophage suspension. The bacteriophage was completely specific against E. coli and the other strains were no susceptible to it. After one-hour incubation of bacteriophage suspension at ۴۰-۷۰oC, the titers of phage were completely preserved. But at ۸۰oC the titer was reduced from ۱۰۱۲ to ۱۰۱۰. Phage titers were completely preserved after incubation of phage suspension (۳۷oC, ۱h) at pH ۴-۱۰, but at pH ۱, ۲, ۳, ۹, ۱۰, ۱۱, ۱۲ the phage titer was reduced from ۱۰۱۲ to ۱۰۹ respectively.Conclusion : Temperature and pH tolerance of this phage was appropriate and it also specifically lysed E. coli. It also had great potential for lysing the XDR E. coli. According to the results, this phage has a good potential for wound phage therapy, food preservation and biocontrol of the environment.

کلیدواژه ها:

bacteriophage ، phage therapy ، XDR ، E. coli