A Novel N4-Like Bacteriophage Isolated from a Wastewater Source in South India with Activity against Several Multidrug-Resistant Clinical Pseudomonas aeruginosa Isolates

Abstract

Multidrug-resistant community-acquired infections caused by the opportunistic human pathogen <i>Pseudomonas aeruginosa</i> are increasingly reported in India and other locations globally. Since this organism is ubiquitous in the environment, samples such as sewage and wastewater are rich reservoirs of <i>P. aeruginosa</i> bacteriophages. In this study, we report the isolation and characterization of a novel <i>P. aeruginosa</i> N4-like lytic bacteriophage, vB_Pae_AM.P2 (AM.P2), from wastewater in Kerala, India. AM.P2 is a double-stranded DNA podovirus that efficiently lyses the model strain, PAO1, at a multiplicity of infection as low as 0.1 phage per bacterium and resistance frequency of 6.59 × 10^-4 Synergy in bactericidal activity was observed between AM.P2 and subinhibitory concentrations of the antibiotic ciprofloxacin. Genome sequencing of AM.P2 revealed features similar to those of the N4-like <i>P. aeruginosa</i> phages LUZ7 and KPP21. As judged by two independent assay methods, spot tests and growth inhibition, AM.P2 successfully inhibited the growth of almost 30% of strains from a contemporary collection of multidrug-resistant <i>P. aeruginosa</i> clinical isolates from South India. Thus, AM.P2 may represent an intriguing candidate for inclusion in bacteriophage cocktails developed for various applications, including water decontamination and clinical bacteriophage therapy.<b>IMPORTANCE</b> In India, multidrug resistance determinants are much more abundant in community-associated bacterial pathogens due to the improper treatment of domestic and industrial effluents. In particular, a high bacterial load of the opportunistic pathogen <i>P. aeruginosa</i> in sewage and water bodies in India is well documented. The isolation and characterization of bacteriophages that could target emerging <i>P. aeruginosa</i> strains, representing possible epicenters for community-acquired infections, could serve as a useful alternative tool for various applications, such as phage therapy and environmental treatment. Continuing to supplement the repertoire of broad-spectrum bacteriophages is an essential tool in confronting this problem.