Effects of abiotic factors on the stability and infectivity of polyvalent coliphage

Abstract

Bacteriophage has attracted growing interest as a promising therapeutic agent for pathogenic bacteria, especially for antibiotic-resistant bacteria. However, the various abiotic conditions could impact the stability of phages and further threat host–virus interactions. Here, we investigated the stability and lytic activity of virulent polyvalent coliphage (named PE1) by double-layer plaque assay. PE1 can efficiently infect both the drug-sensitive Escherichia coli K12 and multidrug-resistant E. coli NDM-1 even after prolonged storage at 4 °C for up to two months. Results showed that PE1 exhibits an outstanding stability to infect E. coli strains under a wide range of thermal (4 °C–60 °C) and pH (4–11) conditions, which covers the thermal and pH variations of most wastewater treatment plants. Moreover, PE1 exhibited high resistibility to heavy metals exposure including Cu2+, Cd2+, Co2+, and Cr3+ at the concentrations below 0.5 mM, and an excellent resistant ability to the variation of ionic strength, which still retained strong infectious ability even treated with saturated sodium chloride solution (350 g/L). This work shows that polyvalent phage PE1 has a strong adaptive capacity to various abiotic factors and should be a good candidate of being an antibacterial agent, especially for antibiotic-resistant bacteria control in sewage. HIGHLIGHTS A virulent polyvalent coliphage named PE1 can propagate fast and effectively in both drug sensitive and drug resistant bacteria even after it has been stored for two months.; PE1 exhibited a strong resistant ability to the variations of common environmental factors including thermal, pH, ionic strength and several heavy metals, which could be a good candidate to be used as the antibacterial agent.;

Keywords

• abiotic factor
• antibiotic resistant bacteria
• escherichia coli
• phage stability
• polyvalent bacteriophage