FIGURE 4.

Functional release assay. Standard Foley catheters and interpenetrating polymer network (IPN) catheters were loaded with 8 ml of sparfloxacin 50 μg ml^–1 and submerged into 1 L of sterile NaCl solution. Samples were collected from the media every other day after which the media was changed. Aliquots were inoculated with UTI89 and incubated ON to evaluate antibacterial activity. The suspensions were plated to quantify viable bacteria. Media retrieved from bottles with Foley catheters (blue dots) did not prevent bacterial growth as CFU reached levels similar to the positive control (saline + inoculum, green line). In contrast, no viable bacteria were detected in media from bottles with IPN catheters (red dots) for the monitoring period of 30 days. Data represents means ± SD from three independent experiments. MBC, minimum bactericidal concentration; LOD, limit of detection (50 CFU ml^–1).