Therapeutic Characterization and Efficacy of Bacteriophage Cocktails Infecting Escherichia coli, Klebsiella pneumoniae, and Enterobacter Species

Abstract

Infections due to antibiotic resistant bacteria are increasing globally and this needs immediate attention. Bacteriophages are considered an effective alternative for the treatment of bacterial infections. The aim of this study was to isolate and characterize the bacteriophages that infect Escherichia coli , Klebsiella pneumoniae , and Enterobacter species. For this, clinical bacterial isolates of the mentioned species were obtained from diagnostic centers located in Chennai, Tamil Nadu, India. The bacteriophages were isolated from sewage water samples collected from Tamil Nadu, India. Phage isolation was performed using enrichment method and agar overlay method was used to confirm the presence of bacteriophages. All the phages were characterized for their life cycle parameters, genome analysis, and in vitro phage cocktail activity. The three bacteriophages exhibited broad host range activity: Escherichia virus myPSH2311 infecting E. coli belonging to six different pathotypes, Klebsiella virus myPSH1235 infecting K. pneumoniae belonging to four different serotypes and Enterobacter virus myPSH1140 infecting four different species of Enterobacter . Morphological observations suggested that the bacteriophages belonged to, Phieco32virus ( Escherichia virus myPSH2311), Podoviridae ( Klebsiella virus myPSH1235), and Myoviridae ( Enterobacter virus myPSH1140). The life cycles (adsorption, latent period, and cell burst) of Escherichia virus myPSH2311, Klebsiella virus myPSH1235 and Enterobacter virus myPSH1140 were found to be 26, 40, and 11 min, respectively. Genomic analysis revealed that Escherichia virus myPSH2311 is closely related to Escherichia phage vB_EcoP_SU10, Klebsiella virus myPSH1235 is closely related to Klebsiella phage vB_KpnP_KpV48 and Enterobacter virus myPSH1140 is closely related to Enterobacter phage PG7 and Enterobacter phage CC31. When phage cocktail was used against multiple bacterial mixtures, there was a reduction in bacterial load from 10 6 to 10 3 CFU/mL within 2 h. All the three characterized phages were found to have a broad host range activity and the prepared phage cocktails were effective against mixed bacterial population that are resistant to meropenem and colistin, two last resort antibiotics. Infections caused by drug resistant bacteria will be a serious threat in the future and the use of virulent bacteriophages in therapy may offer an effective...

Characterization of Lytic Bacteriophages Infecting Multidrug-Resistant Shiga Toxigenic Atypical Escherichia coli O177 Strains Isolated From Cattle Feces

“…The EOP was calculated as the ratio between the average number of plaques on target host bacteria (PFUs) and average number of plaques of reference host bacteria (PFUs). The EOP was classified as high (EOP ≥ 0.5), moderate (EOP > 0.01 < 0.5), and low (EOP ≤ 0.1) based on the reproducible infection on the targeted bacteria (25). The following formula was used to calculate EOP values:…”

Secondary Bacterial Infections During Pulmonary Viral Disease: Phage Therapeutics as Alternatives to Antibiotics?

“…Some filamentous phages allow the host to continue to grow and divide while the phages are being produced ( Loh et al, 2017 , 2019 ; Kuhn and Leptihn, 2019 ). Phage therapy was discovered before antibiotics but the opportunities from the “dawn of the antibiotic era” delayed pursuit of commercial therapeutic phage strategies ( Pirisi, 2000 ; Housby and Mann, 2009 ; Manohar et al, 2019c ). With increasing AMR, and depletion of antibiotic resources, phage therapy has once more piqued the interest of the scientific community and pharmaceutical industry ( Seguin et al, 2006 ; Nyangacha et al, 2017 ; Manohar et al, 2019c ; Loh and Leptihn, 2020 ).…”

“…Phage therapy was discovered before antibiotics but the opportunities from the “dawn of the antibiotic era” delayed pursuit of commercial therapeutic phage strategies ( Pirisi, 2000 ; Housby and Mann, 2009 ; Manohar et al, 2019c ). With increasing AMR, and depletion of antibiotic resources, phage therapy has once more piqued the interest of the scientific community and pharmaceutical industry ( Seguin et al, 2006 ; Nyangacha et al, 2017 ; Manohar et al, 2019c ; Loh and Leptihn, 2020 ). Phages and phage-derived therapeutic proteins have advantages and disadvantages as compared with antibiotic therapies ( Figure 3 ).…”

Phages from Ganges River curtail in vitro biofilms and planktonic growth of drug resistant Klebsiella pneumoniae in a zebrafish infection model

“…The phage belonged to Siphoviridiae that harbored rosette like tail tip with depolymerase activity against capsular type K2 antigen and based on genome sequence analysis, it was classi ed under novel Kp36like virus (Hoyles et al 2015). Cocktail of phages isolated from Ganges river and sewage water against Escherichia coli, K. pneumoniae and Enterobacter spp effectively reduced mixed bacterial load (resistant to carbapenem and colistin) (Manohar et al 2019). Phage kpssk3 (Podoviridae) was isolated from sewage, had a very short latent period of 10 min and a larger burst size of 200 pfu/cell, which was able to lyse 25 clinical isolates of Carbapenem resistant K. pneumoniae (Shi et al 2020).…”