Phages of Pseudomonas aeruginosa: response to environmental factors and in vitro ability to inhibit bacterial growth and biofilm formation

Abstract

To examine effects of various environmental factors on adsorption and inactivation of Pseudomonas aeruginosa-specific phages: δ (family Podoviridae), J-1, σ-1 and 001A (family Siphoviridae) and their ability to inhibit bacterial growth and biofilm formation. The phages examined in the study were clonally different, as revealed by RFLP. The temperature in the range 7-44°C had no influence on the adsorption of Podoviridae, but did affect Siphoviridae adsorption, particularly 001A. All phages were significantly stable at pH 5-9, and phages δ and 001A even at pH 3. Most of the examined carbohydrates and exopolysaccharides of the original host efficiently inactivated phage δ, while phages σ-1 and J-1 were inactivated considerably only by the amino acid alanine. Silver nitrate efficiently inactivated all the phages, while Siphoviridae were more resistant to povidone-iodine. Serum of nonimmunized rats had no influence on phage inactivation and adsorption. Only phage δ showed ability to effectively inhibit in vitro bacterial growth and biofilm formation. The examined environmental parameters can significantly influence the adsorption and viability of Ps. aeruginosa-specific phages. The phage δ is a good candidate for biocontrol of Ps. aeruginosa. The study provides important data on Ps. aeruginosa-specific phage adsorption, inactivation and in vitro lytic efficacy.