Synergistic potential of bacteriophage and blue light therapy against biofilm-associated Klebsiella pneumoniae in postoperative gynaecological infections.

BACKGROUND

Klebsiella pneumoniae, a prominent member of the ESKAPE pathogen group (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species), represents a serious concern in postoperative gynaecological infections due to its multidrug resistance (MDR) and strong biofilm-forming ability. The limited efficacy of conventional antibiotics against such infections underscores the need for innovative combinatorial strategies, such as bacteriophage therapy and phototherapy.

AIMS: This study aimed to evaluate the synergistic antibacterial potential of bacteriophage therapy and blue light (450 nm) phototherapy against biofilm-associated MDR K. pneumoniae isolated from a post- cesarean wound infection.

METHODS

A clinically isolated MDR K. pneumoniae strain was characterised, and biofilms were treated with phage, blue light, or sequential phage-light combinations. Crystal violet assays and microscopy quantified biofilm biomass reduction, while synergy was analysed using the Bliss independence model. Phage stability under blue light and cytocompatibility with HiFi™ human PBMCs were also assessed, along with cytokine profiling.

RESULTS

The combined phage-blue light treatment achieved an 82.3% reduction in biofilm biomass, significantly surpassing either monotherapy (p < 0.0001). Sequence-dependent synergy was observed, with Phage→Light treatments showing stronger early effects (6 h). Phage viability remained unaffected by blue light, and PBMC assays confirmed high cytocompatibility with no detectable cytokine induction. Mechanistically, blue light-induced ROS disrupted the biofilm matrix, facilitating enhanced phage penetration and infection.

CONCLUSIONS

Bacteriophage-blue light combination therapy represents a safe, synergistic, and resistance-mitigating approach for managing MDR K. pneumoniae biofilm infections, offering promising translational potential in postoperative gynaecological wound care.