The identification of the true nature of pseudofungus structures as polyurethane catheter fragments

Pseudofungus structures in lymph node tissues have been reported on multiple occasions. Despite a variety of investigative tests including histochemical special stains and energy dispersive spectral analysis, the underlying nature and origin of these pseudofungus structures has never been clearly defined. The most common hypothesis suggests that they represent collagen fibers that become coated with iron and calcium. Herein, evidence is given that the pseudofungus structures identified in the lymph node tissues represent fragments of polyurethane catheters. The evidence includes both a comparison of these pseudofungus structures to fragments of polyurethane well documented in the literature and a comparison of polyurethane catheter scrapings to the pseudofungus structures identified in the literature. In both of these comparisons, the morphology of the polyurethane fragments are identical to the pseudofungus structures. This is the first definitive report identifying polyurethane catheter fragments as representing the true nature and etiology of pseudofungus structures in lymph node tissues.

Totally Implantable Venous Access Device (Chemoport) in Oncology: Study of 168 Polyurethane Chemoport Catheter System

Background Chemoport (totally implantable venous access device) and its catheter system are used to administer long-term chemotherapy in cancer patients. The objective of this study was to analyze the complications associated with chemoport insertion in various cancer patients. Material and Methods A total number of 168 chemoports along with polyurethane catheters were inserted in various cancer patients over a period of 3 years. 9.6 F polyurethane catheters were put by a team of surgical oncologists in operation theater under general or local anesthesia. Analysis of the complications was done until the chemoport was removed due to any reason. Results Out of 168 patients, 30 (17.85%) developed complications. Complications included arterial puncture, malposition of the catheter tip, pneumothorax, hematoma, seroma, deep vein thrombosis, fracture of the catheter, a reversal of port, infections, and thrombosis of the catheter. Only a few required premature port and catheter removal. Conclusion There was a low rate of complications associated with chemoport using a polyurethane type of catheter system. However, infection-related complications were comparatively more common in our series. Chemoport requires expert handling, patient education, strict follow-up, and dedicated teamwork to minimize complications.

Long peripheral catheters in neonates: filling the gap between short peripheral catheters and epicutaneous-caval catheters?

Introduction: Non-critically ill neonates at times require venous access to provide peripherally compatible infusions for a limited period (more than 3 days). In such a situation, short peripheral cannulas are not appropriate as their average duration is about 2 days, while—on the other hand—epicutaneous-caval catheters may be too invasive. In these patients, insertion of long peripheral cannulas may be an effective option. Methods: In this observational retrospective study, we revised all “long” peripheral catheters (4 and 6 cm long) inserted by direct Seldinger technique in our neonatal intensive care unit when peripheral venous access was required for more than 3 days. Results: We inserted 52 2Fr polyurethane catheters, either 4 cm long ( n = 25) or 6 cm long ( n = 27) in 52 patients. Mean dwelling time was 4.17 days (range 1–12). Most devices were inserted in the cephalic vein ( n = 18, 35%), and the rest in the saphenous vein ( n = 11, 21%) and other superficial veins. There was no significant correlation between the duration of the device and type of infusion ( p = 0.40). The main complications were infiltration ( n = 16, 31%) and phlebitis ( n = 8, 15%). The rate of removal due to complications was significantly higher ( p < 0.01) in neonates with bodyweight <2000 g at the time of insertion. Conclusion: In our experience, 2 Fr 4–6 cm long peripheral catheters may be a valid option for neonates requiring peripherally compatible infusions for more than 3 days. The limits of this study are the necessity of training in the technique of insertion and the small size of our sample. The longest dwell was observed in neonates weighing >2000 g at the time of LPC insertion.

Critical Drug Loss Induced by Silicone and Polyurethane Implantable Catheters in a Simulated Infusion Setup with Three Model Drugs

Silicone and polyurethane are biocompatible materials used for the manufacture of implantable catheters, but are known to induce drug loss by sorption, causing potentially important clinical consequences. Despite this, their impact on the drugs infused through them is rarely studied, or they are studied individually and not part of a complete infusion setup. The aim of this work was to experimentally investigate the drug loss that these devices can cause, on their own and within a complete infusion setup. Paracetamol, diazepam, and insulin were chosen as models to assess drug sorption. Four commonly used silicone and polyurethane catheters were studied independently and as part of two different setups composed of a syringe, an extension set, and silicone or polyurethane implantable catheter. Simulated infusion through the catheter alone or through the complete setup were tested, at flowrates of 1 mL/h and 10 mL/h. Drug concentrations were monitored by liquid chromatography, and the silicone and polyurethane materials were characterized by ATR-IR spectroscopy and Zeta surface potential measurements. The losses observed with the complete setups followed the same trend as the losses induced individually by the most sorptive device of the setup. With the complete setups, no loss of paracetamol was observed, but diazepam and insulin maximum losses were respectively of 96.4 ± 0.9% and 54.0 ± 5.6%, when using a polyurethane catheter. Overall, catheters were shown to be the cause of some extremely high drug losses that could not be countered by optimizing the extension set in the setup.

Isolation and characterisation of bacteriophages from the human skin microbiome that infect Staphylococcus epidermidis

Phage therapy might be a useful approach for the treatment of nosocomial infections; however, only few lytic phages suitable for this application are available for the opportunistic pathogen, Staphylococcus epidermidis. In the current study, we developed an efficient method to isolate bacteriophages present within the human skin microbiome, by using niche-specific S. epidermidis as the host for phage propagation. S.epidermidis was identified on the forehead of 92% of human subjects tested. These isolates were then used to propagate phages present in the same skin sample. Plaques were observable on bacterial lawns in 46% of the cases where S. epidermidis was isolated. Eight phage genomes were genetically characterized, including the previously described phage 456. Six phage sequences were unique, and spanned each of the major staphylococcal phage families; Siphoviridae (n = 3), Podoviridae (n = 1), and Myoviridae (n = 2). One of the myoviruses (vB_SepM_BE06) was identified on the skin of three different humans. Comparative analysis identified novel genes including a putative N-acetylmuramoyl-L-alanine amidase gene. The host-range of each unique phage was characterized using a panel of diverse staphylococcal strains (n = 78). None of the newly isolated phages infected more than 52% of the S. epidermidis strains tested (n = 44), and non-S. epidermidis strains where rarely infected, highlighting the narrow host-range of the phages. One of the phages (vB_SepM_BE04) was capable of killing staphylococcal cells within biofilms formed on polyurethane catheters. Uncovering a richer diversity of available phages will likely improve our understanding of S. epidermidis-phage interactions, which will be important for future therapy.

Quaternary Tannic Acid with Improved Leachability and Biocompatibility for Antibacterial Medical Thermoplastic Polyurethane Catheters

Surfaces of indwelling catheters offer sites for the adherence of bacteria to form biofilms, leading to various infections. Therefore, the development of antibacterial materials for catheters is imperative. In this...