Urinary tract infection is a major global health problem with 70%-80% being catheter-associated. Causative bacteria have become increasingly resistant to antibiotics. Intermittent catheter (IC) technology has progressed, making ICs easier to use and more comfortable (with hydrophilic properties) but little research exists on different activating agents for reduction of CAUTI. Recent research demonstrated that chlorhexidine gluconate (CHG) solutions significantly reduce pathogenic organisms on hydrophilic implant discs [1,2]. This study aimed to evaluate the ability of CHG antiseptics to kill bacteria after inoculation of common UTI pathogens on sterile IC disks as a potential strategy for reducing CAUTI.

In-vitro microbiological studies compared outcomes of catheter activation with 0.05% CHG wash solution (Irrisept™) and 0.05% CHG lube (Endosgel™) vs sterile water using a previous described protocol [3]. Three bacteria were inoculated onto two different catheter discs from Hydrophilic Cure Catheter™ and GentleCath™ Glide with FeelClean™ technology, an integrated amphiphilic surfactant that modifies surface properties. Bacterial strains tested were: Bacteroides fragilis, Enterococcus faecalis and Escherichia coli. For each challenge, 3×1 cm discs of catheter material were activated in the agents for 2 minutes, inoculated with bacteria suspension (~10^9 CFU/mL), left at room temperature for 2-3 minutes to mimic self-catheterisation, then neutralised. Following incubation, bacteria were counted from 3-replicates for each condition.

Both GentleCath and Cure catheters demonstrated substantially reduced bacterial load when using CHG wash and lube compared to sterile water control, which had no effect on microbial colony count reduction. The most potent combination was that of CHG lube and a GentleCath catheter resulting in a significant 3-log reduction in E. coli bacterial load (3.04 log reduction). For B. fragilis, CHG lube showed higher efficacy with log reductions of 0.6 (Cure) and 0.89 (GentleCath) compared to CHG wash at 0.09 (Cure) and 0.19 (GentleCath). Similarly, for E. faecalis, CHG lube demonstrated better antimicrobial activity with log reductions of 0.54 (Cure) and 0.34 (GentleCath) versus CHG wash at <0.01 (Cure) and 0.38 (GentleCath).

The significant reduction in bacterial load, particularly the 3-log reduction in E. coli with CHG lube on GentleCath catheters, suggests a synergistic effect between antimicrobial agents and catheter surface properties. The superior performance of GentleCath may be attributed to its integrated amphiphilic surfactant (FeelClean™ technology), which potentially enhances the interaction between the antimicrobial agents and the catheter surface. This technology alters the surface properties in a way that might improve both the distribution and retention of antimicrobial agents. The differential effect observed across bacterial species likely reflects variations in cell wall structure and composition, with gram-negative E. coli showing greater susceptibility than gram-positive E. faecalis or anaerobic B. fragilis. Previous studies have shown that CHG maintains effectiveness against organisms regardless of their antibiotic resistance profiles, which is particularly relevant given the rising concern of antibiotic-resistant uropathogens. The quantitative methodology used in this study provides more precise assessment of antimicrobial efficacy compared to traditional zone of inhibition methods commonly reported in urological literature.

This study demonstrates that antimicrobial activating agents, particularly 0.05% CHG, can significantly reduce bacterial colonisation on intermittent catheters, with effects varying based on both the activating agent and catheter surface technology. The 3-log reduction in E. coli with CHG lube on GentleCath suggests that matching appropriate antimicrobial agents with specific catheter surface technologies could be a promising strategy for CAUTI prevention. This approach offers several advantages: it doesn't require development of new catheter materials, can be implemented within existing catheterisation protocols, and addresses the growing concern of antibiotic resistance. Multiple cytotoxicity studies have demonstrated the safety profile of 0.05% CHG, supporting its potential clinical application. Clinical validation studies are needed to determine real-world efficacy and safety.

Barry AL, Fuchs PC, Brown SD. Lack of effect of antibiotic resistance on susceptibility of microorganisms to chlorhexidine gluconate or povidone iodine. Eur J Clin Microbiol Infect Dis. 1999;18(12):920-1.
Pan S, Rodriguez D, Thirumavalavan N, et al. The Use of Antiseptic Solutions in the Prevention and Management of Penile Prosthesis Infections: A Review of the Cytotoxic and Microbiological Effects of Common Irrigation Solutions. J Sex Med. 2019;16(6):781-790.
Griggs R, Karpman E, Jones L, Twomey C, Henry G. Effect of 0.05% chlorhexidine gluconate in water on the hydrophilic inflatable penile prosthesis: biocompatibility, adherence, and dip time. J Sex Med. 2023;20(1):113-117.