The Antibacterial Effects of Cocktail and Single Forms of Lytic Phages Belonging to Podoviridae and Myoviridae Families from Sewage against Shigella sonnei and Shigella flexneri

Development and application of a bacteriophage cocktail for Shigella flexneri biofilm inhibition on the stainless steel surface

Food contamination and biofilm formation by Shigella in food processing facilities are major causes of acute gastrointestinal infection and mortality in humans. Bacteriophages (phages) are promising alternatives to antibiotics in controlling plankton and biofilms in food matrices. This study isolated two novel phages, S2_01 and S2_02, with lytic activity against various Shigella spp. From sewage samples. Transmission electron microscopy revealed that phages S2_01 and S2_02 belonged to the Caudovirales order. On characterizing their lytic ability, phage S2_01 initially exhibited relatively weak antibacterial activity, while phage S2_02 initially displayed rapid antibacterial activity after phage application. A combination of these phages in a 1:9 ratio was selected, as it has been suggested to elicit the most rapid and sustained lysis ability for up to 24 h. It demonstrated lytic activity against various foodborne pathogens, including six Shigella spp. The phage cocktail exhibited biofilm inhibition and disruption abilities of approximately 79.29% and 42.55%, respectively, after 24 h in a 96-well microplate. In addition, inhibition (up to 23.42%) and disruption (up to 19.89%) abilities were also observed on stainless steel surfaces, and plankton growth was also significantly suppressed. Therefore, the phage cocktail formulated in this study displays great potential as a biological control agent in improving food safety against biofilms and plankton.

Enhancement of bactericidal effects of bacteriophage and gentamicin combination regimen against Staphylococcus aureus and Pseudomonas aeruginosa strains in a mice diabetic wound model

Diabetic patients are more susceptible to developing wound infections resulting in poor and delayed wound healing. Bacteriophages, the viruses that target-specific bacteria, can be used as an alternative to antibiotics to eliminate drug-resistant bacterial infections. Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus) are among the most frequently identified pathogens in diabetic foot ulcers (DFUs). The aim of this study was assessment of bacteriophage and gentamicin combination effects on bacterial isolates from DFU infections. Specific bacteriophages were collected from sewage and animal feces samples and the phages were enriched using S. aureus and P. aeruginosa cultures. The lytic potential of phage isolates was assessed by the clarity of plaques. We isolated and characterized four lytic phages: Stp2, Psp1, Stp1, and Psp2. The phage cocktail was optimized and investigated in vitro. We also assessed the effects of topical bacteriophage cocktail gel on animal models of DFU. Results revealed that the phage cocktail significantly reduced the mortality rate in diabetic infected mice. We determined that treatment with bacteriophage cocktail effectively decreased bacterial colony counts and improved wound healing in S. aureus and P. aeruginosa infections, especially when administrated concomitantly with gentamicin. The application of complementary therapy using a phage cocktail and gentamicin, could offer an attractive approach for the treatment of wound diabetic bacterial infections.

Antibacterial effects of single phage and phage cocktail against multidrug-resistant Klebsiella pneumoniae isolated from diabetic foot ulcer

Diabetic foot ulcer (DFU) is associated with long-term hospitalization and amputation. Antibiotic resistance has made the infection eradication more difficult. Hence, seeking alternative therapies such as phage therapy seems necessary. Bacteriophages are viruses targeting specific bacterial species. Klebsiella pneumoniae (K. pneumoniae) is among causative agents of the DFU. In this study, the therapeutic effects of single phage and phage cocktail were investigated against multidrug-resistant (MDR) K. pneumonia isolated from DFU. Bacteriophages were isolated from animal feces and sewage samples, and were enriched and propagated using K. pneumoniae as the host. Thirty K. pneumoniae clinical isolates were collected from hospitalized patients with DFU. The antibiotic susceptibility pattern was determined using agar disk diffusion test. The phages' morphological traits were determined using transmission electron microscopy (TEM). The killing effect of isolated phages was assessed using plaque assay. Four phage types were isolated and recognized including KP1, KP2, KP3, and KP4. The bacterial rapid regrowth was observed following each single phage-host interaction, but not phage cocktail due to the evolution of mutant strains. Phage cocktail demonstrated significantly higher antibacterial activity than each single phage (p < 0.05) without any bacterial regrowth. The employment of phage cocktail was promising for the eradication of MDR-K. pneumoniae isolates. The development of phage therapy in particular, phage cocktail is promising as an efficient approach to eradicate MDR-K. pneumoniae isolated from DFU. The application of a specific phage cocktail can be investigated to try and achieve the eradication of various infections.