Design of a Broad-Range Bacteriophage Cocktail That Reduces Pseudomonas aeruginosa Biofilms and Treats Acute Infections in Two Animal Models

Abstract

The alarming diffusion of multidrug-resistant (MDR) bacterial strains requires investigations on nonantibiotic therapies. Among such therapies, the use of bacteriophages (phages) as antimicrobial agents, namely, phage therapy, is a promising treatment strategy supported by the findings of recent successful compassionate treatments in Europe and the United States. In this work, we combined host range and genomic information to design a 6-phage cocktail killing several clinical strains of Pseudomonas aeruginosa, including those collected from Italian cystic fibrosis (CF) patients, and analyzed the cocktail performance. We demonstrated that the cocktail composed of four novel phages (PYO2, DEV, E215 and E217) and two previously characterized phages (PAK_P1 and PAK_P4) was able to lyse P. aeruginosa both in planktonic liquid cultures and in biofilms. In addition, we showed that the phage cocktail could cure acute respiratory infection in mice and treat bacteremia in wax moth (Galleria mellonella) larvae. Furthermore, administration of the cocktail to larvae prior to bacterial infection provided prophylaxis. In this regard, the efficiency of the phage cocktail was found to be unaffected by the MDR or mucoid phenotype of the pseudomonal strain. The cocktail was found to be superior to the individual phages in destroying biofilms and providing a faster treatment in mice. We also found the Galleria larva model to be cost-effective for testing the susceptibility of clinical strains to phages, suggesting that it could be implemented in the frame of developing personalized phage therapies.

Development of a Bacteriophage Cocktail to Constrain the Emergence of Phage-Resistant Pseudomonas aeruginosa

“…For example, a 6-phage cocktail formulated against a broad host range of P. aeruginosa initially killed with great efficiency. As expected, phage-resistant mutants grew to a high density in vitro after only overnight incubation (Forti et al, 2018). However, in the mice and larvae infection model, the phage cocktail resistant mutants are not observed (Forti et al, 2018).…”

“…Moreover, P. aeruginosa strains are frequently resistant to multiple classes of antibiotics (Lopez-Causape et al, 2018), and P. aeruginosa is a member of the ESKAPE pathogens (Boucher et al, 2009), which include six pathogens with well-recognized abilities to develop antibiotic resistance and cause deadly clinical outbreaks. With the emergence of multidrug-resistant isolates of P. aeruginosa (Sun et al, 2013;Lopez-Causape et al, 2018), phage therapy has received renewed attention (Forde and Hill, 2018;Jault et al, 2018;Kortright et al, 2019), and is a promising alternative approach for treating recalcitrant P. aeruginosa infections (Roach et al, 2017;Waters et al, 2017;Forti et al, 2018;Jault et al, 2018).…”

“…The host range of a phage treatment can be expanded by incorporating several phages with different host-range specificities within a cocktail. The host range and killing efficiency of phage cocktails targeting P. aeruginosa have been studied in vitro and in vivo (Roach et al, 2017;Forti et al, 2018). Phage resistance is a somewhat more difficult problem to address, as bacteria have evolved a number of different mechanisms to defend themselves against bacteriophages, including prevention of phage adsorption and DNA injection, restriction enzymes, and CRISPR/Cas systems (Hyman and Abedon, 2010).…”

Pseudomonas aeruginosa PA5oct jumbo phage impacts planktonic and biofilm population and reduces its host virulence

“…Finding a solution to the antibiotic resistance problem is one of the greatest challenges of modern science and medicine, and the search for alternative strategies to antibacterial therapy has led to a renewed appreciation of bacteriophages (Wittebole et al , 2014). Phage therapy efficacy studies (Galtier et al , 2017; Roach et al , 2017; Forti et al , 2018) and recent advances in the regulatory frame, in which phage therapy can be adopted as part of ‘Magistral preparations’ (Pirnay et al , 2018) have shifted the focus from proving the efficacy of phage therapy to its operational implementation, while expanding the number of phage isolates available the design of therapeutic cocktails.…”

Optimizing the Timing and Composition of Therapeutic Phage Cocktails: A Control-theoretic Approach

“…bials, including phage [Kortright et al, 2019, Chan et al, 2013, Kutter et al, 2015, Young and Gill, 2015, Merril et al, 2003, Chan et al, 2016, Schooley et al, 2017, Forti et al, 2018, Dufour et al, 2019. Phage has been applied in compassionate use scenarios, for example, to successfully cure patients both in the USA and in Europe [McCallin et al, 2019, Dedrick et al, 2019, Chan et al, 2018, Schooley et al, 2017, Jennes et al, 2017, catalyzing the 2018 launch of the first North American phage therapy center based at UCSD (IPATH).…”