Efficacy of three lytic bacteriophages for eradicating biofilms of multidrug-resistant Proteus mirabilis

Area of Science:

• Microbiology
• Virology
• Infectious Diseases

Background:

• Proteus mirabilis is a frequent cause of catheter-associated urinary tract infections (CAUTIs).
• This bacterium forms multidrug-resistant (MDR) biofilms, complicating treatment.
• Antibiotic resistance in P. mirabilis necessitates alternative therapeutic strategies.

Purpose of the Study:

• To isolate and characterize novel bacteriophages active against MDR P. mirabilis.
• To evaluate the efficacy of these phages, individually and as a cocktail, against P. mirabilis biofilms.
• To explore bacteriophage therapy as a potential biocontrol agent for CAUTIs.

Main Methods:

• Isolation and partial characterization of three bacteriophages (vB_PmiM-ES1a, vB_PmiM-ES1b, vB_PmiM-ES1c).
• Morphological identification using Transmission Electron Microscopy (TEM).
• Assessment of lytic activity, host range, stability (temperature, pH), one-step growth kinetics, restriction enzyme digestion, and genome size estimation.
• Evaluation of a phage cocktail's efficacy against MDR P. mirabilis biofilms.

Main Results:

• Three novel myovirus-like bacteriophages were isolated and characterized.
• Phages showed strong lytic activity against planktonic and biofilm forms of MDR P. mirabilis.
• Phages were stable across a range of temperatures and pH values.
• One-step growth kinetics revealed lysis times around 180 minutes and significant burst sizes.
• A phage cocktail effectively reduced and eradicated MDR P. mirabilis biofilms.

Conclusions:

• The isolated bacteriophages possess characteristics suitable for therapeutic applications.
• A phage cocktail comprising vB_PmiM-ES1a, vB_PmiM-ES1b, and vB_PmiM-ES1c shows promise as a biocontrol agent.
• Bacteriophage therapy represents a viable alternative for combating MDR P. mirabilis infections, particularly CAUTIs.