Rapid hydrogel-based phage susceptibility test for pathogenic bacteria.

Area of Science:

• Microbiology
• Biotechnology
• Infectious Diseases

Background:

• Antibiotic resistance necessitates alternative treatments like phage therapy.
• Phage therapy requires selecting specific phages due to their narrow host range.
• Rapid phage selection is crucial for effective personalized phage therapy.

Purpose of the Study:

• To develop a rapid hydrogel-based liquid phage susceptibility assay (PST).
• To establish a "ready-to-screen" plate concept for phage storage.
• To optimize PST for different bacterial strains and phages.

Main Methods:

• Tested four hydrogels (GrowDex, Askina, Purilon, Intrasite) as phage matrices.
• Optimized PST using GrowDex with 23 bacterial strains and 23 phages.
• Evaluated chemical stabilizers (trehalose, hyaluronic acid, gelatin) for phage stability over six months.

Main Results:

• GrowDex hydrogel proved optimal for PST, showing no bacterial inhibition and good phage release/viability.
• Microscopy-based PST yielded results in 3 hours without pre-culturing; OD-based PST took 5 hours with pre-culturing.
• Gelatin and hyaluronic acid effectively stabilized phages for at least six months in liquid storage.

Conclusions:

• A rapid, hydrogel-based PST using GrowDex is feasible for selecting therapeutic phages.
• The "ready-to-screen" plate concept with stabilizers enhances phage therapy readiness.
• Optimized PST protocols significantly reduce assay time, facilitating personalized treatment approaches.