Comparative Evaluation of Microbial Transfer in Intermittent Catheters: An in vitro Study of Protective Features Against Uropathogens.

Abstract

Purpose: This study evaluated whether protective features incorporated into commercially available intermittent catheter (IC) types reduce microbial transfer contamination during catheterization.

Design: A previously developed in vitro Contamination Touch Transfer Method (CTTM) was used to model microbial transfer during catheter handling and insertion.

Materials and methods: Four hydrophilic intermittent catheters (ICs) from 2 brands (TSC-A, TSC-B; SC-1, SC-2) and 2 French sizes (14 Fr, 16 Fr) were evaluated in an in vitro simulated urinary tract model. The TSC-A and TSC-B incorporated a ring cap, introducer tip, and protective sleeve, whereas SC-1 and SC-2 incorporated a protective sleeve only. To assess microbial contamination under worst-case conditions, the model meatus and operator's gloved hands were inoculated with approximately 10 8 colony-forming units of Candida albicans , Escherichia coli , or Enterococcus faecium . Microbial recovery from catheter segments was analyzed on the log 10 CFU scale using Tobit mixed-effects models to account for enumeration method-specific limits of quantification and experimental replicate effects. Sleeved catheter segments were compared with corresponding unsleeved controls, and catheter-type differences were evaluated for the first 2-inch (5 cm) catheter segment within each microorganism and French size.

Results: Sleeved catheter segments generally showed lower transfer contamination than corresponding unsleeved controls, with 46 of 48 planned comparisons statistically significant after Holm adjustment. There were statistically significant overall catheter-type differences within all 6 Microbe x French size families. TSC catheter types incorporating a ring cap, introducer tip, and sleeve had significantly lower transfer contamination than sleeve-only SC catheter types in 21 of 24 planned cross-type comparisons. Separation was most consistent for C. albicans and E. faecium across both French sizes. For E. coli , TSC catheter types had significantly lower transfer contamination than SC catheter types at 14 Fr, but fewer pairwise comparisons were significant at 16 Fr.

Conclusions: These findings indicate that catheter protective features reduce microbial transfer contamination to the underlying catheter tube. Under this in vitro transfer contamination model, IC designs incorporating a ring cap, introducer tip, and protective sleeve provided more consistent reduction in transfer contamination than sleeve-only designs.