In vitro efficacy of bacteriophages against Extended-spectrum β-Lactamase producing Escherichia coli Isolated from Patients with Urinary Tract Infections

Abstract

Background: Escherichia coli, a gram-negative bacterial pathogen, which harbors extended spectrum β-lactamase enzymes (ESBLs) is the major cause of UTIs. The wide spread emergence and expansion of ESBL producing E. coli among patients with UTIs poses a serious health challenge in the management of UTIs. The current treatment involving use of carbapenems is expensive, therefore there is need to explore the use of other alternative antimicrobial agents such as bacteriophages. Bacteriophages are viruses that infect and lyse bacteria. They have been suggested as an alternative in fighting UTIs resistant to known antibiotics. In this study, we will determine efficacy of lytic bacteriophages against ESBL producing E. coli isolates originally isolated from Urinary tract infections. In addition, the association between phage activity against E. coli and the selected underlying ESBL genes will be determined. Methods: This was a cross sectional study. Study sites included; Mulago Referral Hospital, MBN clinical laboratories and the Microbiology research laboratory at the College of Veterinary Medicine. Archived ESBL E. coli isolates were used. Antimicrobial susceptibility testing was performed by Disk diffusion method. Double disc synergy test was used to confirm the isolates as ESBL producers. E. coli bacteriophages were isolated by Phage enrichment and their efficacy evaluated using Spot lysis assay and Double layer agar technique. Genomic DNA extraction and PCR were carried out to amplify selected ESBL genes. Correlation between the phage sensitivity and presence of the selected ESBL genes was analyzed. Results: We isolated 6 bacteriophages with a broad host range of at least 63.3%. Phage Eco 4 had the highest host range of 74.2%. The in vitro lytic efficacy showed that bacteriophages at MOI of 10 are more effective than MO1 of 0.01 as shown by the reduction in the cfum/ml of the bacterial culture. In this study we had hypothesized that there is an association between phage activity and presence of ESBL genes, however using cross tabulations we conclude at a p value of 0.05 there is no significant difference with the way the phages lyse with or without the ESBL genes. Conclusion: In light of the current challenges to treatment of UTI infections, due to the advent of MDR, E. coli, therapeutic alternatives including use of bacteriophages, have been suggested. This study has shown the potential of bacteriophages to both inhibit and disrupt ESBL E. coli, a major driver of antibiotic resistance.