Vaccination for Patients Receiving Dialysis.

Vaccinating patients receiving dialysis may prevent morbidity and mortality in this vulnerable population. The National Forum of End-Stage Renal Disease Networks (the Forum) published a revised vaccination toolkit in 2021 to update evidence and recommendations on vaccination for patients receiving dialysis. Significant changes in the last 10 years include more data supporting the use of a high-dose influenza vaccine, the introduction of the Heplisav-B vaccine for hepatitis B, and changes in pneumococcal vaccines, including the approval of the PCV15 and PCV20 to replace the PCV13 and PPSV23 vaccines. Additional key items include the introduction of vaccines against severe acute respiratory syndrome coronavirus 2, the virus that causes coronavirus disease 2019 (COVID-19), and a new vaccine to prevent respiratory syncytial virus disease. Historically, influenza and pneumococcal vaccinations were routinely administered by dialysis facilities, and because of possible risks of hematogenous spread of hepatitis B, dialysis providers often have detailed hepatitis B vaccine protocols. In March 2021, COVID-19 vaccines were made available for dialysis facilities to administer, although with the end of the public health emergency, vaccine policies by dialysis facilities against COVID-19 remains uncertain. The respiratory syncytial virus vaccine was authorized in 2023, and how dialysis facilities will approach this vaccine also remains uncertain. This review summarizes the Forum's vaccination toolkit and discusses the role of the dialysis facility in vaccinating patients to reduce the risk of severe infections.

Treatment of severe metformin-associated lactic acidosis with renal replacement therapy and tris-hydroxymethyl aminomethane: a case report.

BACKGROUND: Type B lactic acidosis is a rare but serious side effect of metformin use. The risk of metformin-associated lactic acidosis is elevated in renal or liver impairment, heart failure and in metformin overdose. Metformin-associated lactic acidosis is treated with renal replacement therapy although this can be limited by metformin's large volume of distribution and a patient's hemodynamic instability. Tris-hydroxymethyl aminomethane is a buffer that rapidly equilibrates in liver cells and increases the intracellular pH of hepatocytes. Intracellular alkalosis increases lactate uptake by the liver and can promote gluconeogenesis which results in increased lactate metabolism and decreased lactate production. Unlike intravenous bicarbonate which can worsen acidosis due to carbon dioxide retention and hypocalcemia, tris-hydroxymethyl aminomethane does not generate large amounts of carbon dioxide and can improve cardiac contractility in experimental models. CASE PRESENTATION: We present a case of a 43-year-old African American male who intentionally ingested 480,000 g of metformin. He developed severe metformin-associated lactic acidosis that was refractory to 21 hours of high flux hemodialysis. This was followed by an additional 12 hours of high flux hemodialysis augmented by continuous intravenous infusion of tris-hydroxymethyl aminomethane. After initiating tris-hydroxymethyl aminomethane, the patient had rapid reversal of lactic acidosis and was weaned off vasopressors and mechanical ventilation. CONCLUSIONS: While metformin-associated lactic acidosis can be treated with renal replacement therapy, severe cases of lactic acidosis may not be amenable to renal replacement therapy alone. Through its unique buffer mechanisms, tris-hydroxymethyl aminomethane can be used in conjunction with dialysis to rapidly improve acidosis associated with metformin.

A Point Prevalence Survey of Antimicrobial Usage in New Brunswick Hospitals.

Background: Prevalence surveys are useful tools for assessing the appropriateness of antimicrobial therapy. Objectives: The primary objective was to assess patterns of antimicrobial utilization and appropriateness in New Brunswick hospitals. The secondary objective was to assess the impact of hospital size and the presence of a penicillin allergy label on antimicrobial appropriateness. Methods: A point prevalence survey was conducted of inpatients taking 1 or more systemic antimicrobials during admission to hospitals in New Brunswick. A structured protocol and web-based data collection tool (National Antimicrobial Prescribing Survey) were used for this survey. Data regarding hospital size and presence of a penicillin allergy label were also collected. Antimicrobial utilization was assessed in terms of guideline compliance and appropriateness. Results were summarized descriptively. A χ2 analysis was performed to describe secondary outcomes. Results: Ten hospitals participated, and a total of 2200 patients were admitted at the time of the survey. The overall prevalence of antimicrobial use was 22.7% (500/2200). A total of 648 antimicrobials were ordered. The most frequently prescribed antimicrobials by class were first-generation cephalosporins (14.0%, 91/648), third-generation cephalosporins (11.3%, 73/648), and piperacillin-tazobactam (10.2%, 66/648). The most common indications for antimicrobial therapy were respiratory tract infections (27.3%, 177/648), urinary tract infections (12.2%, 79/648), and intra-abdominal infections (11.4%, 74/648). Compliance with local or regional treatment guidelines, where applicable, was 66.2% (188/284). Provincially, 68.1% (441/648) of the antimicrobial orders were deemed appropriate. Larger centres had substantially higher rates of appropriateness (p < 0.001). The presence of a penicillin allergy label had no impact on appropriateness (p = 0.21). Conclusions: Several opportunities for targeted interventions were identified to improve antimicrobial prescribing, including decreasing the use of broad-spectrum antimicrobials, increasing guideline compliance, and ensuring documentation of antimicrobial duration by prescribers.

Contexte: Les enquêtes de prévalence sont des outils utiles permettant d'évaluer la pertinence de la thérapie antimicrobienne. Objectifs: L'objectif principal consistait à évaluer les modèles d'utilisation des antimicrobiens et leur pertinence dans les hôpitaux du Nouveau-Brunswick. L'objectif secondaire consistait, quant à lui, à évaluer l'effet de la taille de l'hôpital et de la présence d'une étiquette indiquant une allergie à la pénicilline sur la pertinence des antimicrobiens. Méthodes: Une enquête ponctuelle a été menée auprès de patients hospitalisés prenant un ou plusieurs antimicrobiens systémiques lors de leur admission dans des hôpitaux du Nouveau-Brunswick. Un protocole structuré et un outil de collecte de données en ligne (National Antimicrobial Prescribing Survey, ou enquête nationale sur la prescription d'antimicrobiens) ont été utilisés pour cette enquête. Des données concernant la taille de l'hôpital et la présence d'une étiquette indiquant une allergie à la pénicilline ont aussi été recueillies. L'utilisation des antimicrobiens a été évaluée sur le plan de la pertinence et de la conformité aux lignes directrices. Les résultats ont été résumés de manière descriptive. Une analyse χ2 a été effectuée pour décrire les résultats secondaires. Résultats: Dix hôpitaux ont participé, et un total de 2200 patients ont été admis au moment de l'enquête. La prévalence globale de l'utilisation d'antimicrobiens était de 22,7 % (500/2200). Au total, 648 antimicrobiens ont été prescrits. Les antimicrobiens les plus fréquemment prescrits (par classe) étaient les céphalosporines de première génération (14,0 %, 91/648); les céphalosporines de troisième génération (11,3 %, 73/648); et la pipéracilline-tazobactam (10,2 %, 66/648). Les indications les plus courantes de l'antibiothérapie étaient les infections des voies respiratoires (27,3 %, 177/648), les infections des voies urinaires (12,2 %, 79/648) et les infections intra-abdominales (11,4 %, 74/648). Le respect des directives de traitement locales ou régionales, le cas échéant, était de 66,2 % (188/284). À l'échelle provinciale, 68,1 % (441/648) des ordonnances d'antimicrobiens ont été jugées appropriées. Les grands centres avaient des taux de pertinence sensiblement plus élevés (p < 0,001). La présence d'une étiquette indiquant une allergie à la pénicilline n'a eu aucun effet sur la pertinence (p = 0,21). Conclusions: Plusieurs occasions d'interventions ciblées ont été dégagées pour améliorer la prescription d'antimicrobiens, y compris la diminution de l'utilisation d'antimicrobiens à large spectre, une plus grande conformité aux lignes directrices et l'assurance que la durée de l'antimicrobien est consignée par les prescripteurs.

Brevundimonas vesicularis Peritonitis in a Chronic Peritoneal Dialysis Patient.

Gram-negative peritonitis in chronic peritoneal dialysis patients is difficult to treat and may result in catheter loss. Brevundimonas vesicularis is a Gram-negative rod bacterium which rarely causes infections in humans. A 41-year-old male receiving continuous cycling peritoneal dialysis for 5 months developed culture-negative peritonitis. He failed initial empiric treatment with intraperitoneal vancomycin and levofloxacin and thereafter intravenous gentamicin. B. vesicularis resistant to levofloxacin was isolated from the peritoneal fluid 21 days after his initial symptoms. Despite treatment with intravenous ceftriaxone and oral amoxicillin-clavulanate, the infection persisted, which required removal of the peritoneal catheter in order to cure this infection. We describe the features of B. vesicularis infection in our patient and the rarely reported additional cases.

The 2018 Global Point Prevalence Survey of antimicrobial consumption and resistance in 47 Canadian hospitals: a cross-sectional survey.

BACKGROUND: Patient-level surveillance of antimicrobial use (AMU) in Canadian hospitals empowers the reduction of inappropriate AMU and was piloted in 2017 among 14 hospitals in Canada. We aimed to describe AMU on the basis of patient-level data in Canadian hospitals in 2018 in terms of antimicrobial prescribing prevalence and proportions, antimicrobial indications, and agent selection in medical, surgical and intensive care wards. METHODS: Canadian adult, pediatric and neonatal hospitals were invited to participate in the standardized web-based cross-sectional Global Point Prevalence Survey of Antimicrobial Consumption and Resistance (Global-PPS) conducted in 2018. An identified site administrator assigned all wards admitting inpatients to specific surveyors. A physician, pharmacist or nurse with infectious disease training performed the survey. The primary outcomes were point prevalence rates for AMU over the study period regarding prescriptions, indications and agent selection in medical, surgical and intensive care wards. The secondary outcomes were AMU for resistant organisms and practice appropriateness evaluated on the basis of quality indicators. Antimicrobial consumption is presented in terms of prevalence and proportions. RESULTS: Forty-seven of 118 (39.8%) hospitals participated in the survey; 9 hospitals were primary care centres, 15 were secondary care centres and 23 were tertiary or specialized care centres. Of 13 272 patients included, 33.5% (n = 4447) received a total of 6525 antimicrobials. Overall, 74.1% (4832/6525) of antimicrobials were for therapeutic use, 12.6% (n = 825) were for medical prophylaxis, 8.9% (n = 578) were for surgical prophylaxis, 2.2% (n = 143) were for other use and 2.3% (n = 147) were for unidentified reasons. A diagnosis or indication was documented in the patient's file at the initiation for 87.3% (n = 5699) of antimicrobials; 62.9% (n = 4106) of antimicrobials had a stop or review date; and 72.0% (n = 4697) of prescriptions were guided by local guidelines. INTERPRETATION: Overall, three-quarters of AMU was for therapeutic use across participating hospitals. Canadian hospitals should be further incentivized to create and adapt local guidelines on the basis of recent antimicrobial resistance data.

Atypical anti-glomerular basement membrane glomerulonephritis in a patient with metastatic melanoma treated with mitogen-activated protein kinase and immune checkpoint inhibitors: a case report.

BACKGROUND: Immune checkpoint inhibitors and mitogen-activated protein kinase inhibitors have become the standard of care in patients with advanced melanoma bearing V600 mutations. However, little is known about their nephrotoxicity. To date, only two cases of anti-glomerular basement membrane glomerulonephritis after exposure to checkpoint inhibitors have been documented. Herein, we report the first case of a patient with metastatic melanoma who developed linear Immunoglobulin G 3+, Immunoglobulin A 2+, kappa 2+, lambda 1+ anti-glomerular basement membrane glomerulonephritis with negative serology following treatment with checkpoint inhibitors and subsequently mitogen-activated protein kinase inhibitors. CASE PRESENTATION: A 58-year-old Caucasian male was referred to our outpatient nephrology clinic with acute kidney injury and proteinuria. He had received three cycles of ipilimumab and nivolumab for recurrent melanoma positive for the BRAF V600E mutation with metastasis to the lungs. Immunotherapy had been discontinued in the setting of severe adverse effects including dermatitis, colitis, and hepatitis. Because of persistent bilateral lung metastases and left pleural metastases, the patient had been initiated on dabrafenib and trametinib until his presentation to our clinic 6 months later. On presentation, his blood pressure was 172/89 mm/Hg and had 2+ edema bilaterally. His creatinine level was 2.4 mg/dL from a previous normal baseline with a urinary protein-to-creatinine ratio of 2 g/g. His urinalysis showed dysmorphic erythrocytes and red blood cell casts. Serologic testing was negative for antineutrophilic cytoplasmic antibodies, proteinase 3 antigen, myeloperoxidase, and anti-glomerular basement membrane antibody. Complement levels were normal. A renal biopsy showed focal crescentic (2 of 15 glomeruli with cellular crescents), proliferative, and sclerosing glomerulonephritis with diffuse linear staining of glomerular capillary loops dominant for IgG (3+), IgA (2+), kappa (2+), and lambda (1+) minimal changes. He was initiated on oral cyclophosphamide and pulse intravenous methylprednisolone followed by oral prednisone for 6 months, which stabilized his renal function until reinitiation of immunotherapy. CONCLUSIONS: Acute kidney injury is an increasingly reported adverse effect of both drug classes, mostly affecting the tubulointerstitial compartment and infrequently the glomerulus. Although the biologic effect of these drugs on immune cells is not entirely understood, it is possible that BRAF-induced podocyte injury in combination with direct T-cell-mediated glomerular injury facilitated by checkpoint inhibitors led to the unmasking of cryptic antigens, loss of self-tolerance, and autoimmunity. More importantly, we show that treatment with corticosteroids and cyclophosphamide was able to improve and stabilize our patient's renal function until the reinitiation of immunotherapy.

Derivation and validation of a prognostic model to predict mortality in patients with advanced chronic kidney disease.

BACKGROUND: Guiding patients with advanced chronic kidney disease (CKD) through advance care planning about future treatment obliges an assessment of prognosis. A patient-specific integrated model to predict mortality could inform shared decision-making for patients with CKD. METHODS: Patients with Stages 4 and 5 CKD from Massachusetts (749) and West Virginia (437) were prospectively evaluated for clinical parameters, functional status [Karnofsky Performance Score (KPS)] and their provider's response to the Surprise Question (SQ). A predictive model for 12-month mortality was derived with the Massachusetts cohort and then validated externally on the West Virginia cohort. Logistic regression was used to create the model, and the c-statistic and Hosmer-Lemeshow statistic were used to assess model discrimination and calibration, respectively. RESULTS: In the derivation cohort, the SQ, KPS and age were most predictive of 12-month mortality with odds ratios (ORs) [95% confidence interval (CI)] of 3.29 (1.87-5.78) for a 'No' response to the SQ, 2.09 (95% CI 1.19-3.66) for fair KPS and 1.41 (95% CI 1.15-1.74) per 10-year increase in age. The c-statistic for the 12-month mortality model for the derivation cohort was 0.80 (95% CI 0.75-0.84) and for the validation cohort was 0.74 (95% CI 0.66-0.83). CONCLUSIONS: Our integrated prognostic model for 12-month mortality in patients with advanced CKD had good discrimination and calibration. This model provides prognostic information to aid nephrologists in identifying and counseling advanced CKD patients with poor prognosis who are facing the decision to initiate dialysis or pursue medical management without dialysis.

Continuous cefazolin infusion versus cefazolin plus probenecid for the ambulatory treatment of uncomplicated cellulitis: A retrospective cohort study.

Background: The preferred ambulatory IV therapy for cellulitis is often once-daily cefazolin combined with once-daily oral probenecid (C+P). However, due to a national probenecid drug shortage in 2011, our centre developed a replacement protocol for the administration of cefazolin continuous infusion (CCI) using elastomeric infusers. Our goal was to compare treatment efficacy, duration of IV therapy, and recurrence associated with CCI and C+P using retrospective data from our centre. Methods: We conducted a non-inferiority single-centre retrospective cohort study of emergency department medical records. Patients received either C+P (cefazolin 2 g IV once daily plus probenecid 1 g PO once daily) or CCI (cefazolin 2 g IV loading dose, followed by cefazolin 6 g IV via continuous infusion over 24 hours, via an elastomeric infuser). We compared treatment efficacy, duration of IV therapy, and recurrence rates. Results:  total of 203 patients were analyzed, with 107 included in the CCI arm and 96 in the C+P arm. Overall, CCI users and C+P users were comparable in their sociodemographic and clinical variables measured at admission. We observed increased odds of achieving successful treatment among the CCI group, however it did not reach statistical significance (odds ratio [OR] 2.25; 95% CI 0.84 to 6.07). Recurrence rates were similar between both groups (OR 1.91; 95% CI 0.32 to 11.31). The average duration of IV therapy was similar between groups (p = 0.6). Conclusions: ith results suggesting that CCI was non-inferior to C+P, and that both approaches required similar treatment durations, CCI could represent an acceptable alternative to C+P for the ambulatory IV treatment of cellulitis.

Historique: Le traitement intraveineux (IV) ambulatoire favorisé pour la cellulite prend souvent la forme d'une injection quotidienne de céfazoline associée à une dose quotidienne de probénécide par voie orale (PO) (C+P). Cependant, à cause d'une pénurie nationale de probénécide en 2011, le centre des auteurs a mis au point un autre protocole de perfusion continue de céfazoline (PCC) à l'aide de perfuseurs élastomériques. Les auteurs ont comparé l'efficacité du traitement, la durée du traitement IV et la récurrence associée à la PCC et aux C+P à partir des données rétrospectives du centre. Méthodologie: Les auteurs ont réalisé une étude de cohorte rétrospective monocentrique de non-infériorité à partir des dossiers médicaux du département d'urgence. Les patients ont reçu soit des C+P (2 g de céfazoline IV une fois par jour associés à 1 g de probénécide PO une fois par jour), soit une PCC (dose de charge de 2 g de céfazoline IV, suivie d'une perfusion continue de 6 g de céfazoline IV par perfuseur élastomérique sur une période de 24 heures). Ils ont comparé l'efficacité thérapeutique, la durée du traitement IV et le taux de récurrence. Résultats: Au total, les auteurs ont analysé 203 patients, dont 107 faisaient partie du volet de PCC et 96, du volet de C+P. Dans l'ensemble, les utilisateurs de la PCC et des C+P présentaient des variables sociodémographiques et cliniques semblables à l'admission. Les auteurs ont observé que le traitement du groupe sous PCC avait tendance à être plus efficace, mais cette constatation n'était pas statistiquement significative (rapport de cotes [RC] 2,25; IC à 95 %, 0,84 à 6,07). Les taux de récurrence étaient semblables entre les deux groupes (RC 1,91; IC à 95 %, 0,32 à 11,31). La durée moyenne du traitement IV était semblable entre les groupes (p = 0,6). Conclusions: Puisque, selon les résultats, la PCC n'était pas inférieure aux C+P et que la durée du traitement était semblable dans les deux cas, il serait acceptable comme traitement de rechange acceptable de C+P pour le traitement IV ambulatoire de la cellulite.

Oxcarbazepine Therapy for Complete Central Diabetes Insipidus.

Oxcarbazepine and carbamazepine cause hyponatremia by unknown mechanisms. We describe a patient with complete central diabetes insipidus and seizures who developed worsening hyponatremia when her dose of oxcarbazepine was increased. The patient maintained a normal serum sodium level and has had appropriately concentrated urine for 5 years on just oxcarbazepine, despite undetectable antidiuretic hormone (ADH) levels. This suggests that oxcarbazepine (or one of its metabolites) may stimulate collecting tubule V2 receptor-G protein complex independent of ADH, resulting in increased renal tubular water reabsorption. Oxcarbazepine may be useful as an alternative therapy for patients with central diabetes insipidus.

Hypercalcemia in Lung Cancer due to Simultaneously Elevated PTHrP and Ectopic Calcitriol Production: First Case Report.

Calcitriol-mediated hypercalcemia has been reported in malignant lymphomas and granulomatous diseases but not in lung carcinoma. We describe a patient with squamous cell lung carcinoma with hypercalcemia and elevated calcitriol levels. A 60-year-old Caucasian male patient with stage IIIB squamous cell lung cancer developed hypercalcemia at 14.8 mg/dL two years after receiving chemotherapy and radiotherapy where labs showed a serum intact PTH: 7 pg/mL, PTHrP: 30 pmol/L, 1,25-hydroxyvitamin D (calcitriol): 76 pg/mL, and 25-hydroxyvitamin D levels: <4 ng/mL. Calcitriol levels were elevated despite undetectable 25-hydroxyvitamin D levels. There are no reported lung cancer cases with elevated calcitriol as an etiology of hypercalcemia. We believe that the elevated calcitriol levels in this case were due to a PTHrP-independent mechanism, possibly from either ectopic production of calcitriol in tumor cells or from increased activity of 1-alpha hydroxylase in the same cells. The patient died before the effects of prednisone therapy could be assessed. Studies are needed to investigate the cellular source of calcitriol and its role in hypercalcemia in patients with lung cancer.

Effects of prolonged ethanol lock exposure to carbothane- and silicone-based hemodialysis catheters: a 26-week study.

PURPOSE: Antibiotic locks in catheter-dependent chronic hemodialysis patients reduce the rate of catheter-related bloodstream infections (CRBSIs), but may be associated with the development of resistant bacteria. Ethanol-based catheter locks may provide a better alternative; however, there are limited data on the long-term integrity of dialysis catheters exposed to ethanol. METHODS: We performed in vitro testing of two types of hemodialysis catheters­silicone (SLC) and carbothane (CBT) based­with a 70% ethanol lock (EL) versus heparin lock (HL) for 26 weeks. Lock solutions were changed thrice weekly to mimic a conventional hemodialysis schedule. We tested mechanical properties of the catheters at 0, 13 and 26 weeks by examining stress/strain relationships (SS400%) and modulus of elasticity (ME). Electron microscopy was performed to examine catheter ultrastructure at 0 and 26 weeks. RESULTS: Catheter integrity for HL versus EL in SLC (SS400%: 4.5 vs. 4.5 MPa, p = NS; ME: 4.6 vs. 4.7 MPa, p = NS) or CBT-based catheters (SS400%: 7.6 vs. 8.9 MPa, p = NS; ME: 9.6 vs. 12.2 MPa, p = NS) were all similar at 13 and 26 weeks. Scanning electron microscopy revealed no structural changes in the central and luminal wall internal surfaces of EL- versus HL-treated catheters. CONCLUSIONS: There were no significant differences in catheter integrity between SLC or CBT catheters exposed to a 70% EL for 26 weeks. Given its low cost, potential to avoid antibiotic resistance and structural integrity after 6 months of high-dose ethanol, ELs should be studied prospectively against antibiotic locks to assess the efficacy and safety in hemodialysis patients.

Parainfluenza virus infection associated with posterior reversible encephalopathy syndrome: a case report.

INTRODUCTION: Posterior reversible encephalopathy syndrome is a clinical and radiological entity. The most accepted theory of posterior reversible encephalopathy syndrome is a loss of autoregulation in cerebral blood flow with a subsequent increase in vascular permeability and leakage of blood plasma and erythrocytes, producing vasogenic edema. In infection-associated posterior reversible encephalopathy syndrome, a clinical pattern consistent with systemic inflammatory response syndrome develops. Parainfluenza virus has not been reported in the medical literature to be associated with posterior reversible encephalopathy syndrome. CASE PRESENTATION: We report herein the case of a 54-year-old Caucasian woman with posterior reversible encephalopathy syndrome associated with parainfluenza virus infection who presented with generalized headache, blurring of vision, new-onset seizure and flu-like symptoms. CONCLUSION: Infection-associated posterior reversible encephalopathy syndrome as well as hypertension-associated posterior reversible encephalopathy syndrome favor the contribution of endothelial dysfunction to the pathophysiology of this clinicoradiological syndrome. In view of the reversible nature of this clinical entity, it is important that all physicians are well aware of posterior reversible encephalopathy syndrome in patients presenting with headache and seizure activity. A detailed clinical assessment leading to the recognition of precipitant factors in posterior reversible encephalopathy syndrome is paramount.

Linearization of the response of a 91-actuator magnetic liquid deformable mirror.

We present the experimental performance of a 91-actuator deformable mirror made of a magnetic liquid (ferrofluid) using a new technique that linearizes the response of the mirror by superposing a uniform magnetic field to the one produced by the actuators. We demonstrate linear driving of the mirror using influence functions, measured with a Fizeau interferometer, by producing the first 36 Zernikes polynomials. Based on our measurements, we predict achievable mean PV wavefront amplitudes of up to 30 microm having RMS residuals of lambda/10 at 632.8 nm. Linear combination of Zernikes and over-time repeatability are also demonstrated.

Emergence of gentamicin-resistant bacteremia in hemodialysis patients receiving gentamicin lock catheter prophylaxis.

BACKGROUND AND OBJECTIVES: Antibiotic locks in catheter-dependent chronic hemodialysis patients reduce the rate of catheter-related blood stream infections (CRIs), but there are no data regarding the long-term consequences of this practice. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Over a 4-year period, from October 1, 2002, to September 30, 2006, we initiated a gentamicin and heparin lock (GHL) protocol in 1410 chronic hemodialysis patients receiving dialysis through a tunneled catheter in eight outpatient units. RESULTS: Within the first year of the GHL protocol, our CRI rate decreased from 17 to 0.83 events per 1000 catheter-days. Beginning 6 months after initiation of the GHL protocol, febrile episodes occurred in 13 patients with coagulase-negative Staphylococcus bacteremia resistant to gentamicin. Over the 4 years of GHL use, an additional 10 patients developed 11 episodes of gentamicin-resistant CRI (including 7 with Enterococcus faecalis), in which there were 4 deaths, 2 cases of septic shock requiring intensive care unit admission, and 4 cases of endocarditis. Because of these events, the GHL protocol was discontinued at the end of 2006. CONCLUSIONS: Although the use of GHL effectively lowered the CRI rate in our dialysis population, gentamicin-resistant CRIs emerged within 6 months. Gentamicin-resistant infections are a serious complication of the long-term use of GHLs. Alternative nonantibiotic catheter locks may be preferable to decrease the incidence of CRIs without inducing resistant pathogens.

Semiconductor nanocrystals functionalized with antimony telluride zintl ions for nanostructured thermoelectrics.

The energy efficiency of heat engines could be improved by the partial recovery of waste heat using thermoelectric (TE) generators. We show the possibility of designing nanostructured TE materials using colloidal inorganic nanocrystals functionalized with molecular antimony telluride complexes belonging to the family of Zintl ions. The unique advantage of using Zintl ions as the nanocrystal surface ligands is the possibility to convert them into crystalline metal chalcogenides, thus linking individual nanobuilding blocks into a macroscopic assembly of electronically coupled functional modules. This approach allows preserving the benefits of nanostructuring and quantum confinement while enabling facile charge transport through the interparticle boundaries. A developed methodology was applied for solution-based fabrication of nanostructured n- and p-type Bi(2-x)Sb(x)Te(3) alloys with tunable composition and PbTe-Sb(2)Te(3) nanocomposites with controlled grain size. Characterization of the TE properties of these materials showed that their Seebeck coefficients, electrical and thermal conductivities, and ZT values compared favorably with those of previously reported solution-processed TE materials.