Siphoviridae bacteriophage treatment to reduce abundance and antibiotic resistance of Pseudomonas aeruginosa in wastewater

Wastewater contaminated with the antibiotic-resistant bacteria, Pseudomonas aeruginosa, can contribute to human community-acquired infections when released into receiving waters. This study outlines a novel process of phage application that can reduce the reservoir of P. aeruginosa in both primary wastewater (PWW) and secondary wastewater (SWW). The phage PA25 was first successfully isolated from SWW and is a double-stranded DNA phage, classified as a Siphoviridae family as defined by plaque morphology, electron microscopy and host range. Bacteria such as Pseudomonas are the natural host of this virus; the addition of Siphoviridae PA25 has resulted in the greatest reduction of bacteria from unsterilized PWW compared to unsterilized SWW. Experimental results showed a bacterial reduction of 5ULog discharge in PWW compared only 3ULog in SWW. The addition of PA25 to wastewater can also eliminate streptomycin resistance in P. aeruginosa ATCC strain 27853. Infected P. aeruginosa showed decreased resistance to the antibiotics gentamicin and rifampicin.