Antimicrobial Blue Light Emitting Envelope for the Control of Cardiac Implantable Electronic Device Infections

PROJECT SUMMARY/ABSTRACT Infections related to cardiac implantable electronic devices (CIEDs) are associated with significant morbidity and mortality. The capability of bacteria to form biofilms on CIEDs represents a leading cause of CIED infections. Despite current antibiotic treatments and preventive measures, the incidence of CIED infections

continues to rise. Hence, there is a critical need for the development of alternative strategies to control CIED infections. The objective of this R21 application is to evaluate the potential of a novel antimicrobial blue light (aBL) emitting envelope (aBL-ENV), which emits aBL uniformly across the entire envelope surface, to combat

CIED infections. Our central hypothesis is that aBL-ENV is capable of preventing biofilm formation or eradicating existing biofilms on CIEDs, ultimately reducing the risk of CIED infections. To test this hypothesis, we propose two Specific Aims. In Aim 1, we will conduct in vitro studies to assess the anti-biofilm efficacy of aBL-ENV. Staphylococcus

aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Escherichia coli (including ATTC reference strains and recent clinical isolates), which are the common bacteria identified in CIED infections, will be studied. Biofilms will be formed on aBL-ENVs in the growth medium. To prevent biofilm formation, aBL-

ENVs will be "activated" by aBL within 3 h after bacterial inoculation. To eradicate existing biofilms, aBL-ENVs will be "activated" 24, 48, and 96 h after bacterial inoculation when biofilms of different stages have formed. The efficacy found with aBL-ENVs will be compared with that of clinically used antibiotic-eluting envelopes.

In Aim 2, we will assess the anti-biofilm efficacy and safety of aBL-ENV in vivo using a rabbit model of CIED pocket infections. The clinical isolates of S. aureus and P. aeruginosa that exhibit the highest biofilm-forming capability (identified in Aim 1) will be used as the model pathogens. Immediately after CIED implantation,

animals will be delivered 1 mL of bacterial suspensions (5×103 CFU/mL for S. aureus and 2×104 CFU/mL for P. aeruginosa) into the CIED pockets. To prevent biofilm formation, aBL-ENVs will be activated by aBL within 3 h after bacterial challenge. To eradicate existing biofilms, the activation of aBL-ENVs will be delayed until 24-48

h after bacterial challenge to allow for mature biofilm formation. aBL treatment will be performed twice daily at 8-h intervals for seven days. The bacterial loads of aBL-ENVs and the pocket tissues will then be quantified. To assess the safety of aBL-ENV, the pocket tissue damage will be evaluated using histology at varying time

points (1, 7, and 28 days after treatment). The potential inflammatory response triggered by aBL-ENV will be analyzed by measuring the proinflammatory cytokine profile in the pocket tissue. Additionally, we will determine whether there is a long-term carcinogenic effect associated with aBL-ENV following implantation.

The most important impact of this application resides in its potential to pioneer a new field of study on the novel aBL-ENV to combat CIED infections. The successful completion of the Specific Aims detailed in this application will provide initial preclinical evidence to assess the effectiveness and safety of aBL-ENV.