Novel Lytic Phages Protect Cells and Mice against Pseudomonas aeruginosa Infection

Abstract

With the fast emergence of serious antibiotic resistance and the lagged discovery of novel antibacterial drugs, phage therapy for pathogenic bacterial infections has acquired great attention in the clinics. However, development of therapeutic phages also faces tough challenges, such as laborious screening and time to generate effective phage drugs since each phage may only lyse a narrow scope of bacterial strains. Identifying highly effective phages with broad host ranges is crucial for improving phage therapy. Here, we isolated and characterized several lytic phages from various environments specific for Pseudomonas aeruginosa by testing their growth, invasion, host ranges, and potential for killing targeted bacteria. Importantly, we identified several therapeutic phages (HX1, PPY9, and TH15) with broad host ranges to lyse laboratory strains and clinical isolates of P. aeruginosa with multi-drug resistance (MDR) both in vitro and in mouse models. In addition, we analyzed critical genetic traits related to the high-level broad host coverages by genome sequencing and subsequent computational analysis against known phages. Collectively, our findings establish that these novel phages may have potential for further development as therapeutic options for patients who fail to respond to conventional treatments. IMPORTANCE Novel lytic phages isolated from various environmental settings were systematically characterized for their critical genetic traits, morphology structures, host ranges against laboratory strains and clinical multi-drug resistant (MDR) Pseudomonas aeruginosa, and antibacterial capacity both in vitro and in mouse models. First, we characterized the genetic traits and compared with other existing phages. Furthermore, we utilized acute pneumonia induced by laboratorial strain PAO1, and W19, an MDR clinical isolate and chronic pneumonia by agar beads laden with FDR1, a mucoid phenotype strain isolated from the sputum of a cystic fibrosis (CF) patient. Consequently, we found that these phages not only suppress bacteria in vitro but also significantly reduce the infection symptom and disease progression in vivo, including lowered bug burdens, inflammatory responses and lung injury in mice, suggesting that they may be further developed as therapeutic agents against MDR P. aeruginosa.

Evaluation of Phage Therapy for Pulmonary Infection of Mouse by Liquid Aerosol-Exposure Pseudomonas aeruginosa

“…The mixture was incubated at 37°C for 6 h. The OD600 values were measured at 20 min intervals. 36 Temperature stability of vB_PaeP_PA01EW was tested at 4 °C, 25 °C, 37 °C, 50 °C, 60 °C, 70 °C and 80 °C (pH 7.0) for 120 min. The phage titers were tested by the double-layer agar method.…”

Phage-resistant Pseudomonas aeruginosa against a novel lytic phage JJ01 exhibits hypersensitivity to colistin and reduces biofilm production

“…Phages have the ability to penetrate through biofilms, which are the drug-resistant mechanisms of P. aeruginosa , and kill persistent cells ( Loc-Carrillo and Abedon, 2011 ). Phage therapies using Pseudomonas phages against P. aeruginosa infections have been proven to be successful in many cases worldwide, such as in the treatment of mouse models that were infected with the pathogen in multi-infection sites including lungs ( Debarbieux et al, 2010 ; Morello et al, 2011 ; Chen et al, 2021 ; Yang et al, 2021 ), burn wounds ( McVay et al, 2007 ), cornea ( Fukuda et al, 2012 ), gut ( Watanabe et al, 2007 ), and blood ( Watanabe et al, 2007 ; Yang et al, 2021 ). Phage therapies for P. aeruginosa infection in humans have also been reported ( Wright et al, 2009 ; Khawaldeh et al, 2011 ; Chan et al, 2018 ; Maddocks et al, 2019 ).…”

Clinical Pharmacology of Bacteriophage Therapy: A Focus on Multidrug-Resistant Pseudomonas aeruginosa Infections

“…Though phages are expected to be diluted and available in the body after administration, researchers have found that different routes of administration can lead to variable penetration in the blood (98.5% injection, 66.7% inhalation, 50% topical, and 41.1% oral) [95] due to phage filtration or potential phagocytosis. Gram-negative phage phagocytosis (Escherichia coli T2 phage) and the disintegration of phage virions [18,19,96] have been found to cause immediate reductions of phage counts in the blood after injection, as has been observed in animal models (averaging about 100-fold) [11,89,[96][97][98][99][100].…”

“…Phage therapy is primarily practiced today in parts of Eastern and Western Europe, with a research facility dedicated to phage therapeutics, the Eliava Institute, located in Tbilisi, Georgia [9]. The success of phage therapy for the treatment of P. aeruginosa infections in animals and humans has been validated in several case reports, as well as in small clinical and preclinical trials [10][11][12][13][14][15][16][17]. However, there remains much to be discovered in terms of the pharmacokinetics and pharmacodynamics (PK/PD) of phage therapy, specifically in the context of clinical applications and their role as combination therapy with antibiotics.…”