Lyophilized inserts for nasal administration harboring bacteriophage selective for Staphylococcus aureus: in vitro...

Area of Science:

• Biotechnology
• Microbiology
• Pharmaceutical Sciences

Background:

• Nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) presents a significant infection risk, particularly in hospitalized patients.
• Current strategies for MRSA eradication are limited, and effective nasal formulations for bacteriophage therapy are lacking.

Purpose of the Study:

• To develop and characterize novel lyophilized nasal inserts for bacteriophage delivery.
• To assess the stability and efficacy of bacteriophages within these inserts for MRSA eradication.

Main Methods:

• Bacteriophages were lyophilized in hydroxypropyl methylcellulose (HPMC) with or without mannitol to create porous, leaflet-like nasal inserts.
• Homogeneous distribution of bacteriophages within the matrix was confirmed using fluorescent labeling.
• Bacteriophage titers and stability were assessed post-lyophilization and during storage at 4°C.

Main Results:

• Lyophilized inserts maintained a bacteriophage titer of 10^8 plaque-forming units (pfu) per insert, with a 100- to 1000-fold reduction over 6-12 months of storage.
• Mannitol addition reduced residual water content but did not correlate with lytic activity.
• Mannitol crystallization was observed under humid conditions, but suppressed by higher HPMC concentrations and buffer components.

Conclusions:

• Lyophilized bacteriophage inserts represent a novel and potentially effective strategy for eradicating nasal MRSA.
• The developed formulation demonstrates good bacteriophage stability and offers a promising alternative to current MRSA nasal carriage treatments.