Nitric oxide charged catheters as a potential strategy for prevention of hospital acquired infections

<div><p>Background</p><p>Catheter-Associated Hospital-Acquired Infections (HAI's) are caused by biofilm-forming bacteria. Using a novel approach, we generated anti-infective barrier on catheters by charging them with Nitric Oxide (NO), a naturally-produced gas molecule. NO is slowly released from the catheter upon contact with physiological fluids, and prevents bacterial colonization and biofilm formation onto catheter surfaces.</p><p>Aims and methods</p><p>The aim of the study was to assess the anti-infective properties of NO-charged catheters exposed to low concentration (up to 10³ CFU/ml) of microbial cells <i>in-vitro</i>. We assessed NO-charged tracheal tubes using <i>Pseudomonas aeruginosa</i>, dialysis and biliary catheters using <i>Escherichia coli</i>, and urinary catheters using <i>E</i>. <i>coli</i>, <i>Candida albicans</i> or <i>Enterococcus faecalis</i>. Safety and tolerability of NO-charged urinary catheters were evaluated in a phase 1 clinical study in 12 patients. Six patients were catheterized with NO-charged catheters (NO-group), followed by 6 patients catheterized with regular control catheters (CT-group). Comparison of safety parameters between the study groups was performed.</p><p>Results</p><p>NO-charged tracheal, dialysis biliary and urinary catheters prevented <i>P</i>. <i>aerugino</i>sa, <i>E</i>. <i>coli</i> and <i>C</i>. <i>albicans</i> attachment and colonization onto their surfaces and eradicated corresponding planktonic microbial cells in the surrounding media after 24–48 hours, while <i>E</i>. <i>faecalis</i> colonization onto urinary catheters was reduced by 1 log compared to controls. All patients catheterized with an NO-charged urinary catheter successfully completed the study without experiencing NO-related AE's or serious AE's (SAE's).</p><p>Conclusion</p><p>These data highlight the potential of NO-based technology as potential platform for preventing catheter-associated HAI's.</p></div

NO-charged catheters prevent planktonic microbial growth.

<p>Viable counts of <i>P</i>. <i>aeruginosa</i> and <i>C</i>. <i>albicans</i> (n = 3 for each group per time point) after immersion of NO-charged tracheal and urinary catheter sections in suspension containing 10² CFU/ml of <i>P</i>. <i>aeruginosa</i> and <i>C</i>. <i>albicans</i> and incubation for 24–48 hours at 30°C and 37°C, respectively.</p

Parameters associated with NO-releasing catheter–change from baseline within groups.

<p>Parameters associated with NO-releasing catheter–change from baseline within groups.</p

NO-charged catheters prevent/reduces microbial colonization.

<p>NO-charged and control urinary catheters (<i>n</i> = 3 per group) were divided into 2-cm sections and immersed in contaminated suspensions of 10² CFU/ml of <i>E</i>.<i>coli</i>, <i>C</i>. <i>albicans</i> or <i>E</i>. <i>faecalis</i>. Following 24-hour incubation bacterial and fungal colonization per 1-cm of catheter section was quantitatively assessed after sonication of the catheter sections in fresh saline solution followed by vigorous vortex and plating onto MacConkey (<i>E</i>. <i>coli</i>) or blood agar plates (<i>E</i>. <i>faecalis</i> and <i>C</i>. <i>albicans</i>). Number of colonizing bacteria per 1-cm of catheter was determined the next day.</p

Comparison of parameters associated with NO-releasing catheter–CT versus NO Group.

<p>Comparison of parameters associated with NO-releasing catheter–CT versus NO Group.</p

AE's and SAE's recorded during the study.

<p>AE's and SAE's recorded during the study.</p

NO-charged catheters prevent microbial attachment.

<p>NO-charged and control dialysis, biliary, urinary and tracheal catheters (n = 3 per group) were divided into 2-cm sections and immersed in contaminated suspensions; Dialysis and biliary catheter sections in 10² and 10³ CFU/ml of <i>E</i>. <i>coli</i>, urinary catheter sections in 10² CFU/ml of <i>E</i>.<i>coli</i>, <i>C</i>. <i>albicans</i> or <i>E</i>. <i>faecalis</i> and tracheal catheter sections in 10² CFU/ml of <i>P</i>. <i>aeruginosa</i>. Following 24-hour incubation bacterial and fungal attachment onto the catheters surfaces was qualitatively assessed after rolling of the catheter sections. (A) Comparison of <i>E</i>. <i>coli</i> attachment onto dialysis and biliary catheters rolled onto LB agar plates. (B) Comparison of <i>E</i>. <i>coli</i>, <i>C</i>. <i>albicans</i> and <i>E</i>. <i>faecalis</i> onto urinary catheters rolled onto blood agar plates (upper and lower pictures) or onto MacConkey agar plates (center picture). (C) Comparison of <i>P</i>. <i>aeruginosa</i> attachment onto tracheal catheters rolled onto MH agar plates.</p

Patient Characteristics and baseline measurements.

<p>Patient Characteristics and baseline measurements.</p

Release of NO from charged catheters.

<p>Twenty four hour accumulation of NO in water after release from charged tracheal, dialysis, biliary and urinary catheters (<i>n</i> = 3 for each catheter). NO levels were determined using Griess reaction.</p

Table_2_A clinical evaluation of an ex vivo organ culture system to predict patient response to cancer therapy.docx

IntroductionEx vivo organ cultures (EVOC) were recently optimized to sustain cancer tissue for 5 days with its complete microenvironment. We examined the ability of an EVOC platform to predict patient response to cancer therapy.MethodsA multicenter, prospective, single-arm observational trial. Samples were obtained from patients with newly diagnosed bladder cancer who underwent transurethral resection of bladder tumor and from core needle biopsies of patients with metastatic cancer. The tumors were cut into 250 μM slices and cultured within 24 h, then incubated for 96 h with vehicle or intended to treat drug. The cultures were then fixed and stained to analyze their morphology and cell viability. Each EVOC was given a score based on cell viability, level of damage, and Ki67 proliferation, and the scores were correlated with the patients’ clinical response assessed by pathology or Response Evaluation Criteria in Solid Tumors (RECIST).ResultsThe cancer tissue and microenvironment, including endothelial and immune cells, were preserved at high viability with continued cell division for 5 days, demonstrating active cell signaling dynamics. A total of 34 cancer samples were tested by the platform and were correlated with clinical results. A higher EVOC score was correlated with better clinical response. The EVOC system showed a predictive specificity of 77.7% (7/9, 95% CI 0.4–0.97) and a sensitivity of 96% (24/25, 95% CI 0.80–0.99).ConclusionEVOC cultured for 5 days showed high sensitivity and specificity for predicting clinical response to therapy among patients with muscle-invasive bladder cancer and other solid tumors.</p