Anaslysis: CHL-Fe-based PDT Shows Activity Against Drug-Resistant C. acnes

KEY TAKEAWAYS

• Sodium Iron Chlorophyllin–based (CHL-Fe) photodynamic therapy (PDT) achieved >3 log₁₀ CFU/mL reduction in drug-resistant C. acnes strains, according to new research.

• 7.5 mg/dL CHL-Fe and 3.5 J/cm² red light fluence was found to provide optimal efficacy.

• Researchers noted it provides a nonantibiotic therapy for acne and perioperative infection prevention.

Photodynamic therapy (PDT) using sodium iron chlorophyllin (CHL-Fe) and red light achieved consistent bactericidal effects against drug-resistant Cutibacterium acnes (C. acnes) strains in vitro, according to new study findings.

The study team compared CHL-Fe–based PDT (CH-PDT) against 10 C. acnes strains with diverse resistance profiles (including pan-, extensively, multi-, and single-drug resistance) that were all derived from patients with mild to severe AV. Researcvhers used red light (RL) fluences in combination with CHL-Fe at varying concentrations to deliver a fixed dose of CHL-Fe at 7.5 mg/dL combined with RL at 3.5 J/cm² 

According to the data, this dosage achieved >3 log₁₀ CFU/mL bacterial reduction across all resistant strains. Neither CHL-Fe nor RL alone achieved comparable bactericidal activity.

"These findings underscore CH-PDT as a promising nonantibiotic therapy for drug-resistant AV, with potential implications for eradicating C. acnes colonization and preventing infections in surgical and implant-related settings," the authors wrote.

Source: Mahajindawong, B, et al. Scientific Reports. 2026. Doi:10.1038/s41598-025-34866-8