a National Science Foundation Engineering Research Center in the MSU College of Engineering Center for Biofilm Engineering INTRODUCTION Peripheral IV Blood Control Catheter Design and Biofilm Formation Marcia Ryder 1, Elinor deLancey Pulcini 2, Albert Parker 2, and Garth James 2 (1) Ryder Science, Escondido, CA, (2) Center for Biofilm Engineering, Montana State University-Bozeman Figure 3. Scanning electron microscope image of the white arm within the flow path. The large aggregates of spherical objects Indicate biofilm formation by Staph aureus. Figure 2. Scanning electron microscopic image of the inside of a catheter hub. The small groups of spherical objects are S. aureus cells. The log sum CFU for biofilm formed on all internal fluid pathway surfaces within Smiths Medical ViaValve™ Safety I.V. catheter was 3.84, BD Insyte™ Autoguard™ BC Shielded I.V. Catheter was 4.02, and B.Braun Introcan Safety® 3 catheter was Biofilm was observed on SEM on internal component surfaces with higher CFU counts. When pooled across time points and all experiments, there were statistically significantly smaller bacterial mean log densities in Flush 1 and Flush 2 for the C1 catheter compared to the C2 (p-value = and respectively) or C3 catheters (p-value=0.014 and respectively). METHODS RESULTS CONCLUSIONS DISCUSSION RYDER SCIENCE, Inc. …..medical biofilm research PURPOSE The purpose of the this study is to compare biofilm formation on the various internal components of the catheter hub and bacterial transfer rate between three valved blood control PIVCs in a clinically simulated in vitro model. The insertion of peripheral intravenous catheters (PIVC) is the most common invasive procedure performed by nurses. This places healthcare personnel at risk for needlestick injury and infections related to blood exposure. Manufacturers have responded with a new generation of advanced technologies for PIVC insertion. Valved blood control PIVC (BC-PIVC) technology requires the addition of internal components within the hub to prevent blood exposure to clinicians. These components increase the internal surface area, dead space and volume within the catheter hub that is thought to increase biofilm formation and subsequent transfer of bacteria into the bloodstream. This raises concern for increased risk of bloodstream infection. Three PIVCs were tested: Smiths Medical ViaValve™ Safety I.V. catheter, BD Insyte™ Autoguard™ BC Shielded I.V. Catheter and the B. Braun Introcan Safety® 3 catheter. Six experiments were run with three time points measured within each run: 0, 72 and 96 hours. A needleless connector was attached to each catheter, inoculated by flushing with 0.5 ml of a 10 4 colony forming units per ml (CFU/ml) of S. aureus, and incubated at room temperature for 2 hours. The connectors were then replaced with new sterile connectors and unattached bacteria were rinsed from the fluid path using sterile Phosphate Buffered Saline (PBS). Catheters were then either sampled or subjected to simulated clinical use by flushing 17 times daily with 0.5 ml sterile nutrient and 1 flush at the end of the day with normal saline for 72 and 96 hours. Catheters were sampled with a two-step procedure. First, each catheter was flushed to recover planktonic bacteria and plated to determine CFU/ml (Flush 1). The connector surface was disinfected, sonicated in PBS to remove firmly attached bacteria, and flushed a second time and plated (Flush 2). At Time 96 hours, one of each catheter type was destructively sampled (including all internal components; the hub, spike, septum, etc.). Each part was vortexed, sonicated, and vortexed again to detach and disaggregate the biofilm and form a bacterial suspension for viable plate counts (CFU/ml). One of each assembly type was formalin fixed for scanning electron microscopy (SEM), disassembled and imaged. RESULTS This project was funded by Smiths Medical Inc. This information was provided under a Montana State University Testing Services Agreement and is not intended to endorse or recommend any product or service May 2013 ViaValve™ Safety I.V. Catheter H G F E D C B A B.Braun Introcan Safety® 3 catheter E C B A D As shown in the illustrations and Table 1, the, BD Insyte™ Autoguard™ BC Shielded I.V. Catheter and the B.Braun Introcan Safety® 3 catheters have more complex flow paths than the ViaValve™ Safety I.V. catheter, as well as higher internal surface areas. Flow path irregularities, in particular areas that receive minimal fluid flow, are areas that promote bacterial attachment and biofilm formation. This is analogous to dead-legs and surface irregularities in high purity water systems, which serve as reservoirs for biofilm accumulation and contamination of the system. Introcan 3 luer fitting inserted.208” (halfway between ISO min & max) ViaValve Entire catheter length not shown BD BC entire tube lengths not shown B.Braun Introcan Safety® 3 catheter ViaValve™ Safety I.V. Catheter BD Insyte™ Autoguard™ BC Shielded I.V. Catheter Figure 1. A A A A. Cross-sectional schematic of the catheter hub accessed with syringe. B. Internal volume and surface area in contact with blood (in red). Blood locations used to calculate surface area and volume in Table 1. RESULTS Internal Volume and Surface Area in Contact with Blood Internal surface area (in 2 ) % (2.8 x more SA) ViaValve™ Introcan®3 % difference Internal volume (in 3 ) % (4.5 x more volume) Internal surface area (in 2 ) % (2.1 x more SA) Internal volume (in 3 ) % (2.2 x more volume) ViaValve ™ Autoguard BC™ % difference Table 1. Comparison of the internal volume and surface area of the Autoguard™ BC and the Introcan Safety®3 catheter hubs to the ViaValve™ There are differences in biofilm formation among the devices with higher internal surface areas, volume and dead space. These differences increase the potential risk for transfer of bacteria into the bloodstream among the different blood control valved PIVC designs. ViaValve™ Safety I.V. catheters had statistically significantly fewer bacteria in flush counts compared to both Autoguard™ BC and Introcan® Safety 3. It also had fewer bacteria on internal surfaces as well as a smaller internal surface area and less complex fluid path. These differences may reduce the potential risk for bacterial transfer and bloodstream infection. Figure 5. This three-dimensional reconstruction of confocal scanning laser microscope images shows biofilm growth on a catheter septum. The biofilm was stained with the LIVE/DEAD® BacLight™ Bacterial Viability Kit (Life Technologies Corporation, Carlsbad, CA). Live bacteria appear green. Figure 4. Scanning electron microscopic image of the intraluminal surface of a catheter tubing. The small groups of spherical objects are S. aureus cells. in back of sealin actuator in hub in eyelet in tube (entire length not shown) In and around plunger Introcan 3 B BD BC in & around plunger in seal in hub in eyelet in tube (entire length not shown) B B ViaValve BD Insyte™ Autoguard™ BC Shielded I.V. Catheter Figure 6. Comparison for surface area (in 2 ) and biofilm count (CFU)