In vitro antibacterial activity of NB-003 against Propionibacterium acnes

Area of Science:

• Microbiology
• Dermatology
• Nanotechnology

Background:

• Propionibacterium acnes is a key factor in bacterial skin infections.
• Antibiotic resistance in P. acnes necessitates novel therapeutic approaches.
• NB-003 and NB-003 gel are oil-in-water nanoemulsions developed for treating bacterial infections.

Purpose of the Study:

• To evaluate the in vitro susceptibility of P. acnes to NB-003 formulations.
• To compare the efficacy of NB-003 with existing treatments like salicylic acid and benzoyl peroxide.
• To investigate the impact of sebum and formulation additives (SA, BPO, EDTA) on NB-003's bactericidal activity.

Main Methods:

• In vitro susceptibility testing (MIC/MBC) of P. acnes isolates against NB-003, NB-003 gel, SA, and BPO.
• Evaluation of formulations in the presence and absence of sebum.
• Assessment of combined formulations with SA, BPO, and EDTA.
• Kinetic analysis of bactericidal activity and electron microscopy for morphological changes.
• Spontaneous resistance assessment.

Main Results:

• NB-003 formulations were bactericidal against all tested P. acnes strains, including multidrug-resistant isolates.
• NB-003 showed superior efficacy compared to SA and BPO, especially in the presence of sebum.
• EDTA significantly enhanced NB-003's in vitro efficacy, reducing MIC/MBC values substantially.
• Electron microscopy revealed complete bacterial disruption upon NB-003 treatment.
• No stably resistant P. acnes mutant strains were observed.

Conclusions:

• NB-003 nanoemulsions exhibit potent and broad-spectrum bactericidal activity against P. acnes.
• The addition of EDTA dramatically improves NB-003's efficacy, suggesting a synergistic effect.
• NB-003 represents a promising therapeutic candidate for bacterial infections, particularly those involving antibiotic-resistant P. acnes strains.