The LightCycler (Roche Molecular Biochemicals, Indianapolis, Ind.) is an automated instrument which can monitor the development of amplified target nucleic acid by fluorescence resonance energy transfer after each amplification cycle. The instrument provides rapid (30 to 40 min) PCR results by precise air-controlled temperature cycling; most importantly, the amplification and detection of an amplified product occur in a closed system, which virtually eliminates the likelihood of carryover contamination. In three evaluations that involved 877 dermal and genital and a few ocular specimens and yielded 285 herpes simplex virus (HSV)-and 44 varicella-zoster virus (VZV)-positive results, LightCycler PCR produced a greater sensitivity for the detection of HSV (22%) and VZV (91%) than did the shell vial cell culture assay for the laboratory diagnosis of these viral infections (5, 6, 7). Based on these performance characteristics, together with comparable cost analysis for LightCycler PCR and shell vial cell culture, we implemented the molecular amplification procedure in May 2000 for the routine diagnosis of HSV dermal and genital and VZV dermal infections.Preliminary to LightCycler PCR, we extracted nucleic acids from dermal and genital specimens by the manual IsoQuick (Orca Research, Inc., Bothell, Wash.) procedure. In the present study, we evaluated two automated systems, MagNA Pure (Roche Molecular Biochemicals, Indianapolis, Ind.) and BioRobot 9604 (Qiagen, Inc., Chatsworth, Calif.) as effective replacements for the manual IsoQuick method with the goal of implementing a cost-efficient, standardized system for the processing of clinical specimens. MATERIALS AND METHODSSpecimens and shell vial assay. Genital (n ϭ 152) and dermal (n ϭ 46) swab specimens from patients suspected of having HSV infections were extracted into 2-ml volumes of serum-free medium; the specimen extracts were then divided into four equal aliquots. Each of two shell vial MRC-5 cell cultures received 200 l of inoculum from one aliquot. The vials were centrifuged, incubated overnight at 36°C, and stained by the indirect immunofluorescence test as previously described (10). Nucleic acids were extracted from the remaining aliquots by three different extraction techniques and processed for amplification of HSV DNA by LightCycler PCR. Nucleic acid extracts obtained by each method were stored at 4°C for a maximum of 2 weeks before PCR amplification.IsoQuick nucleic acid extraction. Nucleic acids were extracted manually from a 200-l volume of serum-free extract of genital or dermal swab specimens by the IsoQuick procedure (Orca Research, Inc.), which utilizes guanidine thiocyanate and a noncorrosive extraction reagent, in accordance with the manufacturer's instructions (4, 7).MagNA Pure nucleic acid extraction. A second aliquot (200 l) was extracted by the MagNA Pure LC automated extractor (Roche Molecular Biochemicals) by using the DNA isolation extraction kit produced by the same manufacturer.Qiagen BioRobot 9604 nucleic acid extraction. Another 200-l ...

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Resistant Gram-negative bacteria are increasing central-line-associated bloodstream infection threats. To better combat this, chlorhexidine (CHX) was added to minocycline-rifampin (M/R) catheters. The in vitro antimicrobial activity of CHX-M/R catheters against multidrug resistant, Gram-negative Acinetobacter baumannii, Enterobacter cloacae, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia was tested. M/R and CHX-silver sulfadiazine (CHX/ SS) catheters were used as comparators. The novel CHX-M/R catheters were significantly more effective (P < 0.0001) than CHX/SS or M/R catheters in preventing biofilm colonization and showed better antimicrobial durability. Central venous catheters (CVCs) are essential medical devices in the care of critically ill and cancer patients. Despite their significant usefulness, CVCs are also the source of 87% of the bloodstream infections that occur in intensive care units (1), with attributable mortality rates ranging from 13 to 25% and increases in hospital stays ranging from 7 to 12 days (2, 3). In the United States, more than 5 million CVCs are inserted annually (4, 5) and are responsible for 250,000 to 400,000 annual cases of health careassociated bloodstream infections (6, 7). Hence, central-line-associated bloodstream infections (CLABSIs) are the most common and serious complications associated with indwelling CVCs (5).CVCs coated with antimicrobial agents have been proven to considerably reduce the risk of CLABSIs, and the use of antimicrobial CVCs has become a standard of care (8, 9). Two antimicrobial CVCs, minocycline-rifampin (M/R) and chlorhexidinesilver sulfadiazine (CHX/SS), were clinically proven to reduce CLABSIs at a time when skin-derived, Gram-positive bacteria were the most significant pathogens and were given CDC category 1A recommendations in the most recent guidelines for the prevention of intravascular-catheter-related infections (8-10). However, significant advances in skin antisepsis and sterile barrier precautions have shifted the epidemiologic threat increasingly to Gram-negative bacteria (11). The in vitro efficacy of M/R and CHX/SS against emerging Gram-negative pathogens is limited. In this report, we describe the development of a chlorhexidine-minocycline-rifampin (CHX-M/R) CVC. We compared the antimicrobial adherence activity and durability of M/R, CHX/SS, and CHX-M/R CVCs in a well-established in vitro model for the preventing biofilm colonization by multidrug-resistant clinical isolates of A. baumannii, E. cloacae, E. coli, K. pneumoniae, P. aeruginosa, and S. maltophilia. These organisms were found to contribute to the majority of Gram-negative CLABSIs in the United States from 2009 to 2010 (12). Developing an antimicrobial catheter with broad-spectrum antifungal and antibacterial activity that includes resistant Gram-negative bacteria is of paramount importance because of the mortality rates associated with Gram-negative bacteremia, which may exceed 40% (13,14).CHX-M/R was prepared by a proprietary ...

In cancer patients with long-term central venous catheters (CVC), removal and reinsertion of a new CVC at a different site might be difficult because of the unavailability of accessible vascular sites. In vitro and animal studies showed that a minocycline-EDTA-ethanol (M-EDTA-EtOH) lock solution may eradicate microbial organisms in biofilms, hence enabling the treatment of central line-associated bloodstream infections (CLABSI) while retaining the catheter in situ. Between April 2013 and July 2014, we enrolled 30 patients with CLABSI in a prospective study and compared them to a historical group of 60 patients with CLABSI who had their CVC removed and a new CVC inserted. Each catheter lumen was locked with an M-EDTA-EtOH solution for 2 h administered once daily, for a total of 7 doses. Patients who received locks had clinical characteristics that were comparable to those of the control group. The times to fever resolution and microbiological eradication were similar in the two groups. Patients with the lock intervention received a shorter duration of systemic antibiotic therapy than that of the control patients (median, 11 days versus 16 days, respectively; P < 0.0001), and they were able to retain their CVCs for a median of 74 days after the onset of bacteremia. The M-EDTA-EtOH lock was associated with a significantly decreased rate of mechanical and infectious complications compared to that of the CVC removal/reinsertion group, who received a longer duration of systemic antimicrobial therapy. (This study has been registered at ClinicalTrials.gov under registration no. NCT01539343.) L ong-term central venous catheters have become a lifeline for patients with cancer, those undergoing transplant, or longterm hemodialysis patients. More than five million central venous catheters (CVCs) are inserted annually in the United States, resulting in approximately 400,000 episodes of central line-associated bloodstream infections (CLABSI) and catheter-related bloodstream infections (CRBSI) (1, 2), each associated with an attributable mortality of 12 to 35% (3, 4) and an attributable cost of $34,508 to $56,000 per episode (5). For CLABSI/CRBSI associated with long-term CVCs (including cuffed/tunneled CVCs or ports with a dwell time of Ͼ30 days), the lumen of the catheter is the major source of colonization and subsequent bacteremia (6).The conventional standard of care in the management of CLABSI/CRBSI involves removal of the infected CVC and replacement with a new catheter at a different vascular site (7). However, in cancer, transplant, and hemodialysis patients with long-term catheters, removal of the CVC and reinsertion of a new catheter at a different site might be difficult or even impossible because of the unavailability of accessible vascular sites. Furthermore, these seriously ill patients with CLABSI/CRBSI and sepsis often have underlying thrombocytopenia or coagulopathy, which would make reinsertion of a new CVC at a different site risky given these comorbidities and related mechanical complications, such as blee...

Antimicrobial catheter lock therapy is practiced to prevent lumenal-sourced infections of central venous catheters. Citrate has been used clinically as an anticoagulant in heparin-free catheter locks. Ethanol has also been widely studied as an antimicrobial lock solution component. This study reports on the synergy of glyceryl trinitrate (GTN) with citrate and ethanol in rapidly eradicating methicillin-resistant Staphylococcus aureus, methicillin-resistant Staphylococcus epidermidis, Pseudomonas aeruginosa, and Candida albicans biofilms in an in vitro model for catheter biofilm colonization. GTN has a long history of intravenous use as a hypotensive agent. It is potentially attractive as a component of a catheter lock solution because its physiologic half-life is quite short and its metabolic pathways are known. A lock containing 7% citrate and 20% ethanol required 0.01% GTN to fully eradicate biofilms of all test organisms within 2 h in the model. This GTN concentration is below the levels where clinically significant hypotensive effects are expected. Central line-associated bloodstream infections (CLABSIs) have declined over the past decade but remain a significant medical problem, with a substantial cost burden to the health care system. There are an estimated 250,000 CLABSIs in the United States (1), with an estimated treatment cost of $45,000 or more per infection (2). Significant portions of CLABSIs annually are associated with hemodialysis treatment (3) and treatment of critically ill patients. CLABSIs that present after the first week of catheterization tend to be associated with colonization of the catheter lumenal surfaces (4, 5) and biofilm formation on those surfaces. Colonizing organisms organize within hours into biofilm structures which can serve as a source of CLABSI and can be highly resistant to eradication by antibiotic treatments. Approaches to reducing lumenal colonization include rigorous provider hygiene and use of antimicrobial swabs when connectors are manipulated. Even with these precautions, much of the lumenal surfaces remain vulnerable to colonization. Another approach to combatting lumenal infections has been the use of antimicrobial lock therapy (ALT). Catheter lumens are hydraulically locked when not in use. Typically, lock solutions include anticoagulants to inhibit the formation of blood clots, which can occlude flow through catheters. Heparin has traditionally been used as an anticoagulant; however, there have been concerns about its purity (6), as well as its potential to promote bacterial biofilm colonization (7). Antimicrobial locks have generally fallen into the categories of antibiotic locks and nonantibiotic, antiseptic locks. Antibiotic locks have been pursued both for catheter salvage and for infection prevention. Antibiotic catheter locks have recently been reviewed (8). Significant issues limiting the use of antibiotic locks for prevention are their higher costs and potential to promote the development of antibiotic resistance. We report here on the utility of glycery...

For long-term central lines (CL), the lumen is the major source of central line-associated bloodstream infections (CLABSI). The current standard of care for maintaining catheter patency includes flushing the CL with saline or heparin. Neither agent has any antimicrobial activity. Furthermore, heparin may enhance staphylococcal biofilm formation. We evaluated the safety and efficacy of a novel nonantibiotic catheter lock solution for the prevention of CLABSI. Between November 2015 and February 2016, we enrolled 60 patients with hematologic malignancies who had peripherally inserted central catheters (PICC) to receive the study lock solution. The study lock consisted of 15 or 30 g/ml of nitroglycerin in combination with 4% sodium citrate and 22% ethanol. Each lumen was locked for at least 2 h once daily prior to being flushed. After enrollment of 10 patients at the lower nitroglycerin dose without evidence of toxicity, the dose was escalated to the higher dose (30 g/ml). There were no serious related adverse events or episodes of hypotension with lock administration. Two patients experienced mild transient adverse events (one headache and one rash) possibly related to the lock and that resolved without residual effect. The CLABSI rate was 0 on lock days versus 1.6/1,000 catheter days (CD) off lock prophylaxis, compared with a rate of 1.9/1,000 CD at the institution in the same patient population. In conclusion, the nitroglycerin-based lock prophylaxis is safe and well tolerated. It may prevent CLABSI when given daily to cancer patients. Large, prospective, randomized clinical trials are needed to validate these findings. (This study has been registered at ClinicalTrials.gov under identifier NCT02577718.) KEYWORDS nitroglycerin, catheter, lock solution, central venous catheter, infections, cancer patients C entral venous catheters (CVC) are imperative for the treatment and management of cancer patients, particularly those with hematological malignancies who require a long-term access for the administration of chemotherapy, antibiotics, blood products, and fluids as well as for frequent blood draws. However, these lifelines are the leading source of bloodstream infections, causing at least 400,000 episodes of bloodstream infections yearly in cancer patients (1) and contributing to up to 62% of the bloodstream infections in patients with long-term CVC (2, 3). These catheter-associated infections constitute a major public health challenge, with an estimated mortality rate of 10 to 25% (4) and estimated cost of $45,000 per episode (5).

cThe rapid, broad-spectrum, biofilm-eradicating activity of the combination of 0.01% nitroglycerin, 7% citrate, and 20% ethanol and its potential as a nonantibiotic, antimicrobial catheter lock solution (ACLS) were previously reported. Here, a nitroglycerincitrate-ethanol (NiCE) ACLS optimized for clinical assessment was developed by reducing the nitroglycerin and citrate concentrations and increasing the ethanol concentration. Biofilm-eradicating activity was sustained when the ethanol concentration was increased from 20 to 22% which fully compensated for reducing the citrate concentration from 7% to 4% as well as the nitroglycerin concentration from 0.01% to 0.0015% or 0. C entral line-associated bloodstream infections (CLABSIs) pose a significant public health problem in the United States. More than 7 million patients require central venous access each year, resulting in an estimated 250,000 CLABSIs, approximately 30,000 attributable deaths (1), and substantial treatment costs of at least $45,000 per infection (2). The majority of CLABSIs occur in chronically catheterized patients, such as cancer, hemodialysis, or critical care patients. Long-term catheters, such as central venous catheters (CVCs), peripherally inserted central catheters (PICCs), ports, and dialysis catheters, are susceptible to internal colonization of the catheter lumens due to repeated catheter manipulation and infusions. Biofilm formation on the catheter surfaces can serve as the primary source of CLABSI and can be highly resistant to eradication by systemic antibiotic therapy. Several bundled measures have been proposed for both treatment and prevention of CLABSIs, most of which center around reducing and preventing colonization at the skin insertion site or at connections (3). While bundles have been shown to decrease the risk of CLABSI in short-term CVCs (Ͻ30 days of dwell time), approximately 90% of CLABSIs in longer-term catheters are luminally sourced (4, 5). While antimicrobial coatings exist that do cover luminal surfaces, the duration of protection is limited to only a few weeks (6). Because disinfecting antimicrobial catheter lock solutions (ACLSs) can be repetitively instilled, they have emerged as another approach to prevent luminally sourced CLABSIs.Antimicrobial lock therapy solutions for preventing CLABSI have been reported to include prophylactic applications of antibiotics, antifungals, or antiseptics such as ethanol (EtOH) (7,8). The development of microbial resistance is of great concern with prophylactic antibiotic ACLSs (9). Alternatively, high-concentration antiseptic ethanol ACLSs have been studied. An ACLS consisting of 70% ethanol was not effective in decreasing intraluminal CLABSI and was associated with adverse events such as dizziness (10). Ethanol ACLSs with concentrations of greater than 30% have also been associated with clotting, transient dizziness, and compromising catheter integrity in polyurethane catheters (11). Use of ethanol locks with ethanol concentrations greater than 28% has been further advised ...

Patients receiving parenteral nutrition (PN) as their primary source of nutrition are at high risk for both infectious and noninfectious catheter complications (catheter‐related infections, catheter occlusion, and venous thrombosis). The aim of this review was to synthesize and evaluate what is known about catheter complications and prevention strategies in the PN population. Three electronic databases (Medline, Embase, and CINAHL) were screened for studies published between January 2012 and February 2019 regarding infectious and noninfectious catheter complications in patients receiving PN. Rates of infectious and noninfectious catheter complications, prevalence of causative pathogens, potential risk factors, and prevention strategies via the use of antimicrobial lock therapy (ALT) were assessed. Fifty‐three catheter complication studies and 12 ALT studies were included. Studies were grouped by definition of complication: catheter‐related bloodstream infections (CRBSI) or central line–associated bloodstream infections (CLABSI). Random effects summary rates per 1000 catheter days were 0.85 CRBSI episodes (95% CI 0.27–2.64) and 1.65 CLABSI episodes (95% CI 1.09–2.48). Use of taurolidine or ethanol ALT was efficacious in reducing infectious catheter complications; however, several studies had concerns for adverse mechanical complications. Potential risk factors for catheter complications were highly varied and often contradictory between studies. The rates of catheter complications were higher among catheterized patients receiving PN compared with nationally reported rates of complications in all catheterized patients. Risk factors for catheter complications need to be better understood for targeted prophylactic use of ALT. Future studies are warranted; however, they should be conducted using more standardized definitions and criteria.