In a recent study published in Scientific Reports, researchers investigated whether a cocktail of bacteriophages coding for the depolymerase polysaccharide could effectively disrupt Klebsiella pneumoniae biofilms.

Study: Bacteriophages with depolymerase activity within the control of antibiotic resistant Klebsiella pneumoniae biofilms. Image Credit: AnaLysiSStudiO/Shutterstock.com

Klebsiella pneumoniae has been linked to several illnesses, including pneumonia, urogenital infection, liver abscess, and bloodstream infection. It is particularly harmful to individuals in hospitals, where it may possibly end in ventilator-associated pneumonia or intensive care unit-acquired pneumonia.

The rise of multidrug-resistant and hypervirulent strains, and the capability to construct biofilms on quite a few medical equipment, complicates and renders antibiotics useless in treating such infections. Using bacteriophages to attack Klebsiella pneumoniae biofilms is a viable option.

In regards to the study

In the current evaluation, researchers evaluated the effectiveness of previously identified depolymerase-encoding bacteriophages against Klebsiella pneumoniae biofilms.

In vitro, control of antibiotic-resistant Klebsiella pneumoniae biofilms was achieved using a cocktail of three bacteriophages with depolymerase activity. Bacteriophages obtained from sewage water, vB_KpnM_FZ14, vB_KpnS_FZ10, and vB_KpnP12, were employed within the study. In published investigations, the chosen bacteriophages were evaluated within the in vivo setting as a part of larger phage cocktails.

Prior work used imaging using a three-dimensional Cell Explorer microscope to undertake an in vitro examination of a Klebsiella pneumoniae strain (Kl 315) cell lysis using a mix of chosen pages in real time. The multidrug-recalcitrant Kl 315 strain of Klebsiella pneumoniae was chosen for the bacteriophage efficiency research.

Before being added to the gathering, the Kl 315 bacterial strain was also isolated from a person affected by pneumonia, investigated using mass spectrometry, biochemical, and spectrophotometric tests, and examined for susceptibility to antibiotics using the Clinical Laboratories Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) standards.

To research the characteristics of the phages utilized in the current investigation, the Kl 315 bacterial strain was cultured using Brain Heart Infusion (BHI) agar because the culture medium for 18 hours to evaluate biofilm development.

After 24 hours of biofilm development with Kl 315, 0.10 ml of phage cocktail was incubated in a thermostat with 1.0 x 107 plaque-forming units (PFU) per ml of each bacteriophage or only the vB_KpnP_FZ12 bacteriophage for twenty-four to 48 hours at room temperature.

The effectiveness of a single phage vs. the phage combination in biofilm removal was studied. Optical and scanning electron microscopy (SEM) were used to research biofilms. To check the efficacy of a single phage vs. the triple-phage cocktail on Klebseilla pneumoniae biofilms, the vB_KpnP_FZ12 bacteriophage was chosen as essentially the most prolific on Kl 315.

Results

Using the phage cocktail boosted the preparation’s lytic effectiveness and in addition greatly decreased the phage-resistant form generation risks. Bacteriophage tail proteins showed similarities to bacteriophage proteins with recognized peptidoglycan hydrolase, hyaluronate lyase, and endosialidase domains which degrade polysaccharides.

The titers produced by phage growth within the liquid medium demonstrated that the phages could successfully restrict the event of Klebsiella pneumoniae cultures while also indicating sufficient viral production to realize high concentrations for the ultimate culture evaluation.

The bacteriophage lysis in vitro demonstrated that the chosen bacteriophage cocktail could successfully lyse the K. pneumoniae Kl 315 strain planktonic cells and destroy tiny microcolonies adhering to the glass surface.

After incubating for 48-72 hours, the researchers observed cell clusters and chain formation on top of things slides, common to all bacterial biofilms, whereas only individual cells and tiny colonies were found on the slides to which the bacteriophages were added. 

The antibiofilm activities of the bacteriophage cocktail and the vB_KpnP_FZ12 phage were comparable. Scanning electron microscopy yielded similar results. The outcomes showed that single-phage and three-phage combos with depolymerase activity were successful at controlling antibiotic-resistant K. pneumoniae biofilms.

Complete lysis of K. pneumonia didn’t occur; nevertheless, lysis is difficult to realize using bacteriophages since more intricate pathways regulating bacterial lysis exist even between lytic phages and bacteria, including hibernation, quorum sensing, and transient resistance.

Researchers have discovered naturally vulnerable but phenotypically antimicrobial-resistant bacterial subpopulations; the existence of persistent bacteria within the microbial community might also impact phage infection.

Conclusions

Overall, the study findings showed that the bacteriophage cocktail could successfully disrupt Klebsiella pneumoniae biofilms.

Regardless that a bacteriophage was as effective because the triple-bacteriophage cocktail in disrupting biofilms, bacteriophage combos are advocated for therapeutic use to stop resistance to bacteriophages and improve bacteriolytic effects by widening the range of phage hosts and expanding the goal pathogen spectrum.

The findings emphasized the potential for using the chosen phage cocktail within the early-stage treatment of varied medical devices to avoid biofilm development. In those circumstances where full eradication of biofilms and bacterial colonization is required, combined phage-antibiotic treatment could also be a viable option.