Catheter Segments Research Articles

Modifications to simplify intrathecal irrigation for pyogenic flexor tenosynovitis.

Dear Sir, We describe two modifications to simplify cannulation and passage of fine feeding catheter through flexor sheath for closed irrigation of infective flexor tenosynovitis. Cannulating the flexor sheath and controlled passage of fine feeding catheter through the retinacular system can be difficult due to its pliability, often requiring multiple attempts and causing additional trauma to flexor tendons. Conventionally, irrigation solution is pumped out through the tip of the catheter and intrathecal lavage is dependent on the pressure jet and continuous flow [2]. The potential drawbacks of the latter are incomplete evacuation of infected material and tedious dressings. Other authors have described single and multiple fenestrations along catheter in human and veterinary patients [1, 4]. The advantage of side fenestration is the delivery of irrigation solution to sanctuaries such as the sub-chiasms and intertendinous interfaces. Based on the above techniques, we have modified the closed irrigation technique in two ways to ease cannulation and intrathecal lavage. In all cases, the flexor sheath is visualized and accessed through hemi-Brunner incision centered over A4/5 or A3/4, and a palmar crease incision centered on the A1. The first modification introduces an intraluminal 24-gauge wire to stiffen the tube for cannulation at either A3/4 or A4/5 and retrograde passage to the A1 window (Fig. 1). The second modification involves fenestrating the catheter along its middle portion to increase turbulence of intrathecal flow. During irrigation, the catheter is drawn back and forth, while an assistant flushes the tube after clamping its tip. The end point is the evacuation of clear fluid from the A1 window. Fig. 1 Middle segment of a feeding catheter is marked (black arrows) and fenestrated with a no. 11 blade. Intraluminal 24-gauge wire to increase stiffness of catheter to ease cannulation and manipulation of catheter We believe that the combination of mechanical lavage and fluid flow through the fenestrations increases direct clearance of intrathecal material as opposed to indirect methods that rely on continuous flow (Fig. 2). The catheter is removed after irrigation and postoperative irrigation is not practiced due to the lack of perceived benefits [3]. Fig. 2 Left to right. Direct irrigation—tip of catheter clamped to facilitate intrathecal flow of irrigation fluid (blue arrows), and oscillating motion (thick black arrows) to promote mechanical lavage. Indirect irrigation—flexor sheath is ...

Effect of Human Insulin on the Formation of Catheter-Associated <i>E. coli</i> Biofilms

Biofilm formation is essential for the survival and growth of Escherichia coli in catheter-associated infections. Individuals with type 2 diabetes mellitus can excrete insulin and/or glucose in their urine. This population also has an increased incidence of urinary tract infections. The focus of this study was to determine if the composition of Foley catheter material affects biofilm formation by E. coli in a model system for type 2 diabetes mellitus. Rubber (lubricious-coated), silicon-coated, silver-coated and nitrofurazone-coated catheter segments (5 mm; n = 6) were tested. Catheter segments were added to E. coli ATCC25922 (104 CFU/ml, final concentration) in artificial urine alone, or with insulin (40 μU/ml) and/or glucose (0.1%). After incubation (18 h, 37?C, in air and anaerobically) the level of catheter-associated biofilm was determined by crystal violet staining (Abs550nm). Statistical analysis was done by ANOVA with post-hoc analysis (Tukey). Neither nitrofurazone-coated nor silver-coated catheters supported the formation of E. coli biofilm, regardless of growth condition tested. In contrast, under aerobic biofilm formation on silicon catheters was significantly higher (p E. coli controls. Biofilm formation was also significantly increased (p

The effect of gowning on labor epidural catheter colonization rate: a randomized controlled trial.

The need to gown for labor epidural catheter insertion is controversial. The American Society of Regional Anesthesia and Pain Medicine has identified a lack of randomized controlled trials investigating this issue. The purpose of this study was to examine the effect of gowning on colonization rates following epidural catheter insertion for labor analgesia. Following research ethics board approval and informed written consent, parturients were randomized to undergo epidural analgesia with the anesthesiologist either ungowned or wearing a sterile gown. Cultures were obtained from each of the operator forearms, the work area under the insertion site, and from the epidural catheter tip as well as from the catheter segment adjacent to the insertion site. The primary outcome was growth of any microbial organisms from the cultured sites. Two hundred fourteen patients completed the study. There were no significant differences in catheter-tip colonization rates between the ungowned and gowned groups (9.2% vs 7.6%, respectively). The most common microorganism that was cultured was coagulase-negative Staphylococcus. The use of gowns in the current study did not affect catheter colonization rate. Overall, there was a relatively high incidence of catheter-tip colonization in both groups, which underscores the need for strict aseptic technique.

A case report on the management of a broken haemodialysis catheter in the femoral vein

We are reporting the case of a 24 years old man with end stage renal failure undergoing emergency haemodialysis. His catheter fractured with the distal segment getting lodged in the left femoral vein. Percutaneous extraction of the catheter segment failed and it had to be retrieved through a venotomy performed under local anaesthesia. Catheter fragments in a vein should be promptly extracted to prevent complications such as arrhythmias, perforation of the great vessels and their often fatal embolization to the right heart.

Something's Missing: Peripheral Intravenous Catheter Fracture

We describe a case of peripheral intravenous catheter fracture occurring during a routine training exercise. The supervising instructor immediately placed a venous tourniquet proximal to the insertion site and urgently transported the patient to the hospital. The missing catheter segment was identified within the median cubital vein under ultrasonography and was removed by venous cutdown under local anesthesia. An investigation determined that reinsertion of the needle into the advanced catheter likely caused the fracture and that application of a tourniquet may have prevented embolism of the fractured segment. Our literature review suggested that peripheral intravenous catheter fracture is likely vastly underreported, with only one prior case identified in the English literature. Action was taken following the event to educate all Israeli Defense Force medical providers regarding both proper preventive measures and recognition and treatment of catheter fracture should it occur. This case highlights the importance of health care providers being aware of the possibility of catheter fracture, as well as steps to take to prevent and mitigate its occurrence.

Couple zircone-polyéthylène dans la prothèse totale de hanche : était-ce réellement si mauvais ? Relation entre transformation de phase et survie. Analyse de 45 explants

This study reports the development of a polymer-based catheter coating to facilitate controlled release of antimicrobial peptides (AMP) to target both planktonic bacteria and biofilm in the urinary catheter environment. Catheter associated urinary tract infection (CAUTI) is a common nosocomial infection among hospitalized patients and is a major reservoir of antimicrobial resistant pathogens. Although silver- or antibiotics-coated catheters have been deployed to minimise CAUTI, the inconsistency and lack of durability in antibacterial properties of these coatings have limited their clinical use. The incorporation of AMPs in catheter coatings has gained interest due to the effective bacteria killing effects of AMPs, with few reports on bacterial resistance development against peptides. This study aims to deploy a novel and potentially cost-effective technique to coat an anhydrous polymeric coating impregnated with AMPs for silicone-based catheters, to overcome limitations in conventional hydrogel-based coatings. Sustained peptide release was achieved with the development of an Ethyl Cellulose (EC): 1-Palmitoyl-2-oleoylphosphatidylcholine (POPC)-based diffusion layer over an AMP-laden Polycaprolactone (PCL)-based layer to control AMP diffusion into the environment over a clinically relevant duration. The ‘AMP-EC-PCL’ coating showed good anti-bacteria performance against uropathogenic Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa for up to 6 days. The coating also showed excellent anti-biofilm capability against green fluorescent protein (GFP)-tagged UTI E. coli. Fifteen centimeter catheter segments of single layer ‘AMP-EC-PCL’-coated catheters showed sustainable AMP release kinetics up to 7 days, where good antibacterial and anti-biofilm activity against E. coli was observed. The full scale ‘AMP-EC-PCL’-coated catheter showed improved mechanical integrity compared to commercial silicone catheters with preservation of the catheter balloon integrity upon expansion. Wound healing studies of the coated PDMS samples in mice models showed a reduction in bacteria concentration as compared to uncoated PDMS, indicating in vivo efficacy potential of the developed catheter coating platform.

Arterial catheter-related bloodstream infection: incidence, pathogenesis, risk factors and prevention

Arterial catheters are essential in critical care for haemodynamic and blood gas monitoring. The risk of infection remains ill defined. To delineate the incidence, pathogenesis and risk factors for arterial catheter-related bloodstream infection (BSI). Arterial catheters in two randomized trials in 1998-2000 were studied prospectively. One trial studied the effect of a 1% chlorhexidine-75% alcohol solution for cutaneous antisepsis for intravascular catheters, and the other trial studied the efficacy of a chlorhexidine-impregnated sponge dressing, both for prevention of catheter-related BSI. At catheter removal, skin of the insertion site, catheter segments, hub and infusate were cultured quantitatively in all cases. Catheter-related BSI was confirmed by concordance between isolates from the catheter and from blood cultures by restriction-fragment DNA subtyping. Risk factors for arterial catheter-related BSI were determined using univariate analysis. Of 834 arterial catheters studied (3273 catheter-days), 109 (13%) were colonized and 11 caused bacteraemia (1.3%, 3.4 per 1000 catheter-days). The majority of catheter-related BSIs were acquired extraluminally from skin of the insertion site (63%). The risk of arterial catheter-related BSI was comparable with that for short-term non-cuffed central venous catheters (2.7%, 5.9 per 1000 CVC-days). In patients in intensive care with cryptogenic sepsis or bacteraemia, arterial catheter-related BSI must also be suspected and excluded. The most common route of infection is extraluminal; as such, novel technologies shown to prevent bloodstream infection with CVCs, such as chlorhexidine for cutaneous antisepsis and chlorhexidine-impregnated dressings, may also be of benefit with arterial catheters.

Anti-biofilm activity of low-molecular weight chitosan hydrogel against Candida species

Candida invasive infections have increased in frequency during the last decades. Such infections are often associated to medical indwelling devices like central venous catheter. The recurrent nature and difficulties in the treatment of these infections are often related to biofilm formation. The objective of this study was to investigate the anti-biofilm activity of low-molecular weight chitosan hydrogel (LMWCH), a natural biopolymer obtained from the N-deacylation of crustacean chitin, upon clinical relevant Candida species. The in vitro ability of LMWCH to impair biofilm formation and to disorganize a preformed biofilm was tested in polystyrene microplates and quantified by the semi quantitative XTT assay and by the crystal violet assay. LMWCH in vivo efficacy as a coating for medical indwelling devices was evaluated for the first time for Candida parapsilosis, using a mouse subcutaneous foreign body model using polyurethane catheter segments. Scanning electron microscopy was used to access biofilm architecture after LMWCH treatment. We found that LMWCH efficiently impaired biofilm formation of all Candida species, also promoting biofilm disaggregation. Most importantly, LMWCH was able to significantly inhibit biofilm formation by C. parapsilosis in an in vivo catheter mouse model. SEM images showed biofilm collapsed cells compatible with membrane damage, suggesting that this could be one of the possible mechanisms underlying biofilm impairment. LMWCH revealed to be a promising compound for treatment of candidiasis or its prevention through medical device coating.

Bacteriophage antimicrobial-lock technique for staphylococcus aureus central venous catheter-related infection: an in-vivo evaluation

Purpose Bacteriophages are viruses that selectively infect and kill bacteria. The purpose of this project was to determine whether a bacteriophage antimicrobial lock technique can reduce bacterial colonization and biofilm formation on indwelling central venous catheters in a rabbit model. Materials and Methods This study was performed in 10 female New Zealand white rabbits (weight range 3-4 kg). Broviac catheters (4.2 French, BARD access systems, NJ) were inserted into the jugular vein under image guidance and tunneled in an intrascapular position. Catheters were then inoculated for 24h with broth culture of Methicillin sensitive staphylococcus aureus (0.5 McFarland standard). The inoculate was aspirated and rabbits were randomized into two equal groups for 24h: (i) untreated controls (heparinized saline lock), (ii) Bacteriophage antimicrobial-lock (Staphylococcal Bacteriophage K, propagated titer > 10 8 ). At the completion of the experiment blood cultures were obtained via peripheral veins, the catheters were removed for quantitative culture and scanning electron microscopic analyses, and the animals were sacrificed. Statistical testing for substantial differences in distal catheter segment colonization was carried out using the rank sum test. Results Mean distal catheter segment colony forming units (CFU) per cm 2 as a measure of biofilm was significantly decreased in experimental animals compared to controls (control 1.2 × 10 5 CFU/cm 2 , experimental 7.58 × 10 3 , P=0.016). Scanning electron microscopic analysis of the catheter segments demonstrated qualitative reduction of biofilm in treated catheter segments compared to untreated controls. Blood culture results were not significantly different between the groups (control 3/5 positive (60%), experimental 4/5 positive (80%), (p=1.0). Conclusion In a rabbit model, treatment of infected central venous catheters with a bacteriophage antimicrobial-lock technique significantly reduced bacterial colonization and biofilm presence. Our data suggests that bacteriophage lock solution may be a feasible strategy for prevention and treatment of central venous catheter infections.

LEARNING FROM IMAGES Oops!! Can we Prevent this Fundamental Mistake?

Tunneled central venous catheters (TCVC) are a frequently used vascular access option to initiate hemodialysis across the globe. These TCVC are placed by resident physicians, mid-level providers and physicians from several different subspecialties. TCVC vary in their designs, including the catheter tip and their lengths, though all of them have a polyester cuff that helps secure the catheter in the subcutaneous tunnel. The tips of the TCVC used for dialysis differ widely and may be stepped, split or symmetric in design. Ideal placement of a TCVC in the internal jugular vein involves: 1) Initial venous puncture positioned as low in the neck as possible, thus providing a smooth wide curve to the catheter segment in the subcutaneous tunnel 2) The polyester cuff positioned 1-2 cm from the exit site in the subcutaneous tunnel 3) The exit site located in the infraclavicular region, avoiding the breast tissue and 4) The catheter tip positioned in the mid right atrium A standard teaching and learning process in the medical field involves peer-review and evaluation of fundamental mistakes that physicians encounter in clinical practice. The current images are examples demonstrating improperly placed TCVC providing a resource to the growing international interventional nephrology community to learn and preferably avoid duplicating them. The catheter cuff in Fig. (1) was not only placed deep in the subcutaneous tunnel, but the catheter hub was pushed in all the way up to the exit site. A deeply placed catheter cuff makes removal of these catheters difficult when the TCVC is no longer needed. The catheter in Fig. (2) was removed when it was no longer needed, revealing the trimmed off venous tip of the split-tip design. The tips are manufactured with a smooth surface to avoid endothelial trauma. Trimming of the catheter tip can lead to ragged edges that can cause endothelial trauma and potentially lead to stenosis and thrombosis. Moreover, the venous tip in a TCVC with split-tip is designed to minimize

Pressure Pulse Drive: A Control Method for the Precise Bending of Hydraulic Active Catheters

Our group has been developing a compact, active catheter that can be safely used in human blood vessels. The catheter is driven not by electronic mechanisms, but by a water pressure system with micro valves for multidegrees of freedom. The active catheter is composed of a soft, flexible, MRI-compatible material. In this paper, we propose what we call “pressure pulse drive,” a new control method to precisely bend the active segment. We design a new set of optimized valves for this method and experimentally verify the precise bending motion and simultaneous drive of the two active catheter segments.

Tamm-Horsfall protein facilitates catheter associated urinary tract infection

BackgroundUrinary catheters are associated, commonly with bacteriuria and frequently with urinary tract infection. Tamm-Horsfall Protein (THP) is urine's most abundant protein and is known to bind to uropathogenic bacteria. The role of THP in the pathogenesis of catheter associated urinary tract infection (CAUTI) is not clear. We examined the role of THP in facilitating bacterial binding to urinary catheters in vivo and in vitro.FindingsTwenty one urinary catheters were obtained from 20 hospitalized patients. THP was eluted from the catheter surface and catheter segments were cultured. Additional studies were performed in vitro on unused silicone and latex catheters to determine the binding of THP, and the effect of THP on the binding of Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa), to the catheter surface.On catheters obtained from patients, the THP deposition was significantly more on culture positive catheters than on culture negative catheters. In the in vitro studies, THP bound to both silicone and latex catheters, and THP enhanced the adherence of E. coli and P. aeruginosa to both types of catheters.ConclusionTHP binds to urinary catheters and facilitates the binding of uropathogenic bacteria to catheters.

In vivo antibiofilm effect of cerium, chitosan and hamamelitannin against usual agents of catheter-related bloodstream infections

Catheter-related bloodstream infections (CRBSIs) are common healthcare-associated infections associated with increased morbidity and medical costs. Antiseptic- and antibiotic-coated central venous catheters (CVCs) have been proposed to reduce the incidence of CRBSIs, with variable success. The aim of this study was to determine the in vivo antibiofilm activity of biocompatible and inexpensive compounds, such as cerium nitrate, chitosan and hamamelitannin, against usual agents of CRBSIs. The antibiofilm effect of cerium nitrate, chitosan and hamamelitannin was tested against Staphylococcus epidermidis, Staphylococcus aureus, Acinetobacter baumannii and Candida albicans in a mouse foreign body infection model, using polyurethane catheter segments. Biofilm formation was assessed with a crystal violet assay to quantify the total biomass, with a tetrazolium reduction assay to quantify the metabolic activity and with scanning electron microscopy. At subinhibitory concentrations, cerium nitrate significantly reduced biofilm formation by C. albicans, chitosan significantly decreased biofilm formation by S. epidermidis and C. albicans, and hamamelitannin significantly inhibited all bacterial biofilms. The in vivo antibiofilm effect of cerium nitrate against C. albicans and of chitosan against C. albicans and S. epidermidis, at subinhibitory concentrations, makes them promising alternatives to coat CVCs. Moreover, the microbicidal effect on a wider range of CVC colonizers was previously reported in vitro for both compounds, at higher concentrations. For all bacterial strains, the highest in vivo antibiofilm efficacy was achieved with hamamelitannin. For A. baumannii, this is the first report of in vivo inhibition.

Bacteriophages are synergistic with bacterial interference for the prevention ofPseudomonas aeruginosabiofilm formation on urinary catheters

We hypothesized that pretreating urinary catheters with benign Escherichia coli HU2117 plus an antipseudomonal bacteriophage (ΦE2005-A) would prevent Pseudomonas aeruginosa biofilm formation on catheters--a pivotal event in the pathogenesis of catheter-associated urinary tract infection (CAUTI). Silicone catheter segments were exposed to one of four pretreatments (sterile media; E. coli alone; phage alone; E. coli plus phage), inoculated with P. aeruginosa and then incubated up to 72 h in human urine before rinsing and sonicating to recover adherent bacteria. Pseudomonas aeruginosa adherence to catheters was almost 4 log(10) units lower when pretreated with E. coli plus phage compared to no pretreatment (P < 0.001) in 24-h experiments and more than 3 log(10) units lower in 72-h experiments (P < 0.05). Neither E. coli nor phage alone generated significant decreases. The combination of phages with a pre-established biofilm of E. coli HU2117 was synergistic in preventing catheter colonization by P. aeruginosa. We describe a synergistic protection against colonization of urinary catheters by a common uropathogen. Escherichia coli-coated catheters are in clinical trials; adding phage may offer additional benefit.

Antibiotic impregnated catheter coverage of deep brain stimulation leads facilitates lead preservation after hardware infection

Deep brain stimulation (DBS) has become a reliable and effective treatment for many disorders. However, the risk of long-term hardware-related complications is notable, and most concerning is hardware-related infections. Given the risk of hardware removal in the setting of infection, we retrospectively examined the implementation of a novel technique using antibiotic covered catheter protection of DBS leads after infection. The effect on hardware salvage and ease of reimplantation of the DBS extension and implantable pulse generator (IPG) was examined. A total of nine (9%) out of 100 DBS patients met the inclusion criteria with 11 DBS hardware-related infections at either the frontal, parietal, or IPG sites, from June 2003 to November 2010, at our institution. Subsequent to the initial patient in the series, a total of eight patients had placement of a short segment (approx. 4cm long) of antibiotic impregnated catheter (Bactiseal, Codman, Johnson & Johnson, Raynham, MA, USA) over the distal end of the DBS leads at the parietal incision. Seven of these eight patients presented with pus and deep tissue infections around the hardware at either the frontal, parietal, or chest incisions. In seven of these eight patients (87.5%) we were able to protect and salvage their DBS leads without need for removal. In conclusion, this novel technique provides a simple reimplantation operation, with a decreased risk of DBS lead damage. It may improve the preservation of DBS leads when hardware infection occurs, is inexpensive, and confers no additional risks to patients.

Comparative in vitro efficacies of ethanol-, EDTA- and levofloxacin-based catheter lock solutions on eradication of Stenotrophomonas maltophilia biofilms

The aim of this study was to compare the in vitro activity of ethanol, EDTA and levofloxacin (Levo), alone or in combination, on biofilms of Stenotrophomonas maltophilia recovered from patients with catheter-related bloodstream infections (CRBSIs) at a university hospital in Argentina. First, 24 and 48 h biofilms were formed in microtitre plates and challenged with 25 or 40 % ethanol for 1 h. Biofilms, of the 14 local isolates and from the reference strain K279a, were eradicated after both treatments as shown by plate counts and the regrowth technique. Second, 24 h biofilms of all isolates were established in silicone catheter segments and challenged with 25 or 40 % ethanol, Levo (2.5 mg ml(-1)), EDTA (30 mg ml(-1)), 25 % ethanol-EDTA or Levo-EDTA for 1, 3 and 24 h. Viable counts of biofilms treated for 1 h with 25 or 40 % ethanol or 25 % ethanol-EDTA were under the limit of detection. Killing of biofilms by Levo or Levo-EDTA was gradual and it was only after 24 h of treatment that no differences could be seen between the effects of these catheter lock solutions (CLSs) and those of ethanol (P>0.05). Levo-EDTA, in combination, did not act synergistically against biofilms. After 24 h of exposure, EDTA did not eradicate biofilms but reduced biofilm survival rates to 1-5 %. The effect of the different CLSs on biomass reduction, estimated by crystal violet staining, was highly dependent on the isolate, and the most effective agents were 25 and 40 % ethanol. Our results suggest that when used as a CLS for short periods, ethanol at low concentrations, alone or in combination with a chelator, can decontaminate the line from S. maltophilia in cases of CRBSI and help, in conjunction with systemic antibiotics, in the retention of precious vascular catheters.

Catheter Related Bloodstream Infection (CR-BSI) in ICU Patients: Making the Decision to Remove or Not to Remove the Central Venous Catheter

BackgroundApproximately 150 million central venous catheters (CVC) are used each year in the United States. Catheter-related bloodstream infections (CR-BSI) are one of the most important complications of the central venous catheters (CVCs). Our objective was to compare the in-hospital mortality when the catheter is removed or not removed in patients with CR-BSI.MethodsWe reviewed all episodes of CR-BSI that occurred in our intensive care unit (ICU) from January 2000 to December 2008. The standard method was defined as a patient with a CVC and at least one positive blood culture obtained from a peripheral vein and a positive semi quantitative (>15 CFU) culture of a catheter segment from where the same organism was isolated. The conservative method was defined as a patient with a CVC and at least one positive blood culture obtained from a peripheral vein and one of the following: (1) differential time period of CVC culture versus peripheral culture positivity of more than 2 hours, or (2) simultaneous quantitative blood culture with 5∶1 ratio (CVC versus peripheral).Results53 CR-BSI (37 diagnosed by the standard method and 16 by the conservative method) were diagnosed during the study period. There was a no statistically significant difference in the in-hospital mortality for the standard versus the conservative method (57% vs. 75%, p = 0.208) in ICU patients.ConclusionIn our study there was a no statistically significant difference between the standard and conservative methods in-hospital mortality.

Cerium, chitosan and hamamelitannin as novel biofilm inhibitors?

The colonization of indwelling medical devices and subsequent biofilm formation represents a global challenge since it promotes the persistence of infection and contributes to antimicrobial resistance. The aim of this study was to determine the antimicrobial activity of cerium, chitosan and hamamelitannin against usual microbial colonizers and to assess their efficacy regarding biofilm formation on polyurethane (PUR)-like catheters. The antimicrobial and anti-biofilm effect of cerium nitrate, low molecular weight chitosan (LMWC) and hamamelitannin was tested against Staphylococcus epidermidis, Staphylococcus aureus, Acinetobacter baumannii and Candida albicans strains. Biofilm formation was assessed with PUR-like catheter segments and the metabolic activity was quantified by colorimetry with a tetrazolium reduction assay. Cerium nitrate and LMWC inhibited the microbial growth of all microbial strains tested; hamamelitannin showed no inhibition. Regarding biofilm formation on PUR-like catheters, with subinhibitory concentrations: cerium nitrate significantly inhibited the metabolic activity of C. albicans; LMWC reduced the metabolic activity of S. epidermidis and C. albicans; and hamamelitannin decreased the metabolic activity of all tested bacteria, but not of yeasts. The microbicidal activity of cerium nitrate and LMWC was clearly demonstrated in this study, as was their fungistatic effect at lower concentrations. Hamamelitannin significantly reduced biofilm metabolic activity of all tested bacteria. These microbial inhibitors may play a promising role regarding different biomedical applications.

Diastolic timed Vibro-Percussion at 50 Hz delivered across a chest wall sized meat barrier enhances clot dissolution and remotely administered Streptokinase effectiveness in an in-vitro model of acute coronary thrombosis

BackgroundLow Frequency Vibro-Percussion (LFVP) assists clearance of thrombi in catheter systems and when applied to the heart and timed to diastole is known to enhance coronary flow. However LFVP on a clotted coronary like vessel given engagement over a chest wall sized barrier (to resemble non-invasive heart attack therapy) requires study.MethodsOne hour old clots (n=16) were dispensed within a flexible segment of Soft-Flo catheter (4 mm lumen), weighted, interfaced with Heparinized Saline (HS), secured atop a curved dampening base, and photographed. A ~4 cm meat slab was placed over the segment and randomized to receive intermittent LFVP (engaged, - disengaged at 1 second intervals), or no LFVP for 20 minutes. HS was pulsed (~120/80 mmHg), with the diastolic phase coordinated to match LFVP delivery. The segment was then re-photographed and aspirated of fluid to determine post clot weight. The trial was then repeated with 0.5 mls of Streptokinase (15,000 IU/100 microlitre) delivered ~ 2 cm upstream from the clot.ResultsLFVP - HS only samples (vs. controls) showed; a) development of clot length fluid channels absent in the control group (p < 0.0002); b) enhanced dissolved clot mixing scores ( 5.0 vs. 0.8, p < 2.8 E – 6); and c) increased percent clot dissolution (23.0% vs. 1.8% respectively, p < 8.5 E-6). LFVP - SK samples had a similar comparative clot disruptive profile, however fluid channels developed faster and percent clot dissolution more than doubled (51.0% vs. 3.0%, p< 9.8 E- 6).ConclusionDiastolic timed LFVP (50 Hz) engaged across a chest wall sized barrier enhances clot disruptive effects to an underlying coronary like system.

Differential Time to Positivity and Semi-Quantitative Culture of Catheter Segments for Diagnosing Catheter-Related Bloodstream Infections

Background Catheter-related bloodstream infection (CRBSI) is one of the leading types of infection, with a significant morbidity and mortality rate. We evaluated the differential time to positivity (DTP) and semi-quantitative culture of catheter segments (SQCC) as a method for diagnosing CRBSI. Methods From January 2010 to August 2011, 155 positive paired blood cultures which had the same organism isolated from blood cultures drawn simultaneously through the central venous catheter (CVC) and the peripheral vein were included. Positive DTP represents a DTP of least 120 min earlier for the time to detection of CVC draw than that of a peripheral vein draw. We evaluated the clinical utility of DTP and SQCC for diagnosing CRBSIs, which were further divided into two groups: confirmed (either by DTP or SQCC) and non-confirmed CRBSIs (neither DTP nor SQCC positive). Results Sixty-five percent (100/155) of episodes were confirmed to CRBSIs. In CRBSIs, Gram-positive cocci accounted for 61% of cases, non-fermenting Gram-negative bacilli represented 10%, Enterobacteriaceae for 10%, yeasts for 15%, and others for 4%. Among the confirmed CRBSI cases, 22 were both positive with DTP and SQCC, 30 cases were positive with DTP only, 12 cases were positive with SQCC only, and 36 cases which did not undergo SQCC analysis were DTP positive. The sensitivities of the DTP and SQCC techniques were 88.0% (88/100) and 53.1% (34/64), respectively. Conclusion The differential time to positivity was more sensitive than the semi-quantitative culture of catheter segments for the diagnosis of CRBSIs. DTP is useful for diagnosing CRBSIs without removal of the catheter.