Use of bacteriophage in the treatment of experimental animal bacteremia from imipenem-resistant Pseudomonas aeruginosa

Abstract

Abstract. The emergence of antibiotic-resistant bacterial strains still remains a significant problem for antimicrobial chemotherapy in the clinic. Bacterial viruses (bacteriophages or phages) have been suggested to be used as alternative therapeutic agents for bacterial infections. However, the efficacy of phage therapy in treating drug-resistant infections in humans is uncertain. Therefore in the present study, we examined the effectiveness of phages in the treatment of imipenem-resistant Pseudomonas aeruginosa (IMPR-Pa) infection in an experimental mouse model. Twenty-nine strains of phage were isolated from our hospital sewage, and phage ØA392 was representatively used for all testing because it has lytic activity against a wide range of clinical isolates of IMPR-Pa. We found that intraperitoneal (i.p.) injections of one IMPR-Pa strain (3x10 7 CFU) caused bacteremia and all mice died within 24 h. A single i.p. inoculation of the phage strain (MOI ≥0.01) at up to 60 min after the bacterial challenge was sufficient to rescue 100% of the animals. This lifesaving effect coincided with the rapid appearance of ØA392 in the circulation (within 2 h after i.p. injection), which remained at substantially higher levels for up to 48 h until the bacteria were eradicated. However, the survival rates of the mice dropped to approximately 50% and 20% when the same dose of this purified phage preparation was administered at 180 min and 360 min, respectively, after IMPR-Pa infections. In addition, we demonstrated that the ability of this phage to rescue bacteremic animals was due to the functional capabilities of the phage and not to a nonspecific immune effect. The protection from death occurred only in animals inoculated with bacteria-specific virulent phage strains. When the heat-inactivated phages were used, the survival rate of the infected mice was dramatically reduced to 20% or lower. Moreover, the levels of the antibody against the phage were not significantly changed at the time when the bacteremic animals were protected by the active phages. Finally, our observations revealed that the inoculation of the mice with high-doses of ØA392 alone produced no adverse effects attributable to the phage. These data indicate that phages can save animals from pernicious P. aeruginosa infections and suggest that phage therapy may be potentially used as a stand-alone therapy for patients with IMPR-Pa infections.

Antibacterial Efficacy of R-Type Pyocins towards Pseudomonas aeruginosa in a Murine Peritonitis Model

“…Phages have recently been used to treat murine peritonitis and bacteremia (7,32,33). Watanabe et al (33) had limited success using lytic bacteriophages to treat peritonitis, whereas Hagens et al (7) showed better efficacy using a lysis-deficient, nonreplicating phage.…”

“…The latter might be predicted based on the ability of bacteriophages to enter the circulating blood rapidly after i.p. administration (5,20,32).…”

Bacteriophages and Their Derivatives as Biotherapeutic Agents in Disease Prevention and Treatment

“…The phage was shown to overcome a high-dose, systemic bacterial infection as well as wound infection in mice. Thus, the study demonstrated that the therapeutic efficacy of the phages was independent of the administration routes, but overall, the timing of administration is very important [57]. Another study focused on the details of multiplicity of infection (MOI) of phage against multidrug-resistant uropathogenic E. coli (UPEC).…”

“…[49], vancomycin-resistant Enterococci [50][51][52], antibiotic-resistant Staphylococci [53,54], multidrugresistant Klebsiella pneumonia [55], imipenem-resistant [56,57] and multidrug-resistant Pseudomonas aeruginosa [58,59], antibiotic-resistant strains of Escherichia coli [60], and methicillin-resistant Staphylococcus aureus [61]. Today, there are several different antibacterial strategies derived from phages including enzybiotics (cloned host-specific, phageencoded lytic enzymes introduced to combat bacteria without the whole phage) and whole-phage therapy (introducing whole, viable phage to attack the infecting bacteria) [8,[62][63][64].…”

Experimental Phage Therapy in Treating Klebsiella pneumoniae -Mediated Liver Abscesses and Bacteremia in Mice

“…Treatment with bacteriophage is associated with numerous advantages over chemotherapy: (i) it is economic and effective against multidrug-resistant bacteria because the mechanisms by which it induces bacteriolysis differ completely from those of antibiotics, (ii) it is safe because it has high specificity for its target and neither disturbs the microflora of the body nor affects eukaryotic cells, and (iii) administration requires only a single dose of treatment, owing to its selfreplicating nature (1,37). Although bacteriophage therapy has been successfully used to treat various diseases in both animals (4,8,10,11,25,32,40,41,44) and humans (1,5,17,37,42), there is no report associated with phage therapy of K. pneumoniae-induced liver abscesses. In the present study, the therapeutic effect of a newly isolated phage (NK5) with lytic activity for K. pneumoniae was evaluated against K. pneumoniae infection.…”