An in-vitro urinary catheterization model that approximates clinical conditions for evaluation of innovations to prevent catheter-associated urinary tract infections.

BACKGROUND: Catheter-associated urinary tract infections (CAUTI) account for approximately 25% of nosocomial infections globally, and often result in increased morbidity and healthcare costs. An additional concern is the presence of microbial biofilms which are major reservoirs of bacteria, especially antibiotic-resistant bacteria, in catheters. Since introduction of the use of closed drainage systems, innovations to combat CAUTI have not led to significant improvements in clinical outcomes. The lack of a robust laboratory platform to test new CAUTI preventive strategies may impede development of novel technologies.

AIM: To establish an in-vitro catheterization model (IVCM) for testing of technological innovations to prevent CAUTI.

METHODS: The IVCM consists of a continuous supply of urine medium flowing into a receptacle (bladder) where the urine is drained through a urinary catheter connected to an effluent collection vessel (drainage bag). Test organism(s) can be introduced conveniently into the bladder via a rubber septa port. Development of bacteriuria and microbial biofilm on the catheter can be determined subsequently.

FINDINGS: With an initial inoculum of Escherichia coli [∼5×105 colony-forming units (cfu)/mL] into the bladder, a 100% silicone catheter and a commercially available silver-hydrogel catheter showed heavy biofilm colonization (∼108 cfu/cm and ∼107 cfu/cm, respectively) with similar bacterial populations in the urine (bacteriuria) (∼108 cfu/mL and ∼107 cfu/mL, respectively) within three days. Interestingly, an antimicrobial peptide (CP11-6A)-coated catheter showed negligible biofilm colonization and no detectable bacteriuria.

CONCLUSION: The IVCM is a useful preclinical approach to evaluate new strategies for the prevention of CAUTI.