Genetically Confirmed Edwardsiella tarda Peritonitis was Associated with Improper Caregiver's Hand Hygiene during Peritoneal Dialysis Bag Exchange.

Edwardsiella tarda is a Gram-negative bacillus and is responsible for waterborne disease. This is the first case report of peritoneal dialysis (PD)-associated peritonitis caused by genetically confirmed E. tarda, which was transmitted from the caregiver's hand during PD bag exchange. Aside from that, the caregiver was a fishmonger and a gastrointestinal carrier of the pathogen. Prior to the onset of peritonitis, the caregiver reported that she did not wash her hands every time when performing the PD bag exchange. Although extraintestinal edwardsiellosis usually poses a poor outcome, PD-associated peritonitis with this species is paradoxical if diagnosed early, and treatment is promptly provided, as presented here. This case emphasizes the importance of hand hygiene in preventing environment-bound infection in patients on PD and demonstrates the unusual route of infection, contamination during PD bag exchange.

Intermittent hypoxia in rat enhancing peritoneal membrane thickening through HIF-1α-induced cytokines in peritoneum.

BACKGROUND: Due to the high prevalence of both obstructive sleep apnea syndrome (OSA) and end-stage renal disease (ESRD), the co-existence of both conditions in peritoneal dialysis is demonstrated. Because OSA-induced chronic intermittent hypoxia is well-known, the hypoxia might worsen peritoneal membrane. OBJECTIVE: We tested the influence of chronic intermittent hypoxia upon peritoneal membrane in a Sprague-Dawley rat model. METHODS: Normal saline or 3.86% glucose peritoneal dialysis fluid (PDF) were intra-peritoneally administered twice a day as negative (NSS group) and positive controls (PDF group), respectively. Intermittent hypoxia was induced by using a hypoxic chamber with 10% O2 for 8 hours a day plus twice-daily NSS injection (IH group). RESULTS: At 12 weeks of the experiments, high serum TNF-α and IL-6 (but not IL-10) with normal renal and liver functions were demonstrated in the IH group (but not the PDF group). In parallel, local cytokines (TNF-α, IL-6, and IL10 in peritoneal membrane) and peritoneal membrane thickness were increased whereas peritoneal membrane hypoxia (hypoxyprobeTM and hypoxia-inducible factor-1α; HIF-1α) was induced in both PDF and IH groups (more prominent in the PDF group). However, the increased vascular density in submesothelial area was established only in the PDF group. CONCLUSION: Intermittent hypoxia model induced local peritoneal membrane inflammation and enhanced peritoneal membrane thickness, at least in part, through a mechanism of hypoxia-induced HIF-1α. Although peritoneal membrane alterations from PDF were more prominent than intermittent hypoxia, the combination between intermittent hypoxia with PDF utilization might facilitate peritoneal membrane failure, which will need more study.

The culture from peritoneal dialysis catheter enhances yield of microorganism identification in peritoneal dialysis-related peritonitis.

An additional yield of culture from the removed peritoneal dialysis (PD) catheter in diagnosis of pathogen causing refractory peritonitis was assessed in 118 eligible patients from 7 PD centers. Peritoneal dialysis fluid (PDF) culture identified organisms in 86 (72.9%) patients, while the catheter culture identified organisms in 55 (46.6%) patients. PD catheter culture could additionally identify organisms in 19 patients whose PDF culture were negative, increasing the positive culture rate to 89%, in other word 16.1% reducing the culture-negative rate. PD catheter culture provided additional yield, especially in fungal and enterococcal infections.

Rhodococcus induced false-positive galactomannan (GM), a biomarker of fungal presentation, in patients with peritoneal dialysis: case reports.

BACKGROUND: Galactomannan index (GMI) at a level higher than 0.5 provides high sensitivity and specificity for the diagnosis of fungal peritonitis. Here, we report the false-positive of GMI in peritoneal dialysis (PD) effluent (PDE) due to Rhodococcus peritonitis in PD patients. CASE PRESENTATION: GMI in PDE of case #1 and case #2 were 1.53 and 0.76, respectively, while serum GMI of both cases was less than 0.5. In addition, GMI from the specimens obtained directly from the stationary phase of Rhodococcus colonies were 1.27 and 1.56, which were isolated from case #1 and #2, accordingly. CONCLUSION: High GMI in PDE of PD patients is not specific just for fungal infections but may also be secondary to other infections, such as Rhodococcus spp., especially in endemic areas.

Peritoneal dialysis (PD) catheter-related peritonitis from Aureobasidium pullulans caused by poor caregiver's hand hygiene.

Catheter-related peritonitis is common but rarely caused by fungal infection. We report the first case of PD patients with catheter-related peritonitis form Aureobasidium pullulans, a black yeast-like dematiaceous fungus, and reviewing the relevant literatures. A potential cause of this infection is poor hand hygiene and improper fingernail care. The infection could be prevented if patient and caregiver strictly follow hand-washing protocols.

Multiple extracellular vesicle types in peritoneal dialysis effluent are prominent and contain known biomarkers.

Peritoneal dialysis inevitability results in activation of inflammatory processes and its efficiency is highly variable between patients. An improved method to isolate biomarkers and study pathophysiological mechanisms in peritoneal dialysis effluent (PDE) is expected to be of much benefit for the development of this treatment approach and help with patient management. Extracellular vesicles (EVs) are released as part of normal cellular processes. Their proteome is expected to reflect both type and health of their cell of origin. Although there is a significant interest in using EVs for "liquid biopsies", little is reported of their presence or composition in plentiful dialysis waste fluids, including peritoneal dialysis effluent (PDE). Here we determined the presence of EVs in PDE and subsequently characterized their proteome. EVs were first isolated from PDE using differential centrifugation, then a further enrichment using size exclusion chromatography (SEC) was performed. The presence of EVs was demonstrated using transmission electron microscopy, and their particle counts were investigated using nanoparticle tracking analysis and dynamic light scattering. Using tandem mass spectrometry, marker proteins from three types of EVs i.e. apoptotic bodies, ectosomes, and exosomes were identified. The proteomic results demonstrated that the isolation of EVs by differential centrifugation helped enrich for over 2,000 proteins normally masked by abundant proteins in PDE such as albumin and SEC markedly further improved the isolation of low abundant proteins. Gene ontology analysis of all identified proteins showed the marked enrichment of exosome and membrane-associated proteins. Over 3,700 proteins were identified in total, including many proteins with known roles in peritoneal pathophysiology. This study demonstrated the prominence of EVs in PDE and their potential value as a source of biomarkers for peritoneal dialysis patients.

The in vitro toxicity of peritoneal dialysis fluid.

OBJECTIVE: To investigate the toxicity of peritoneal dialysis fluid (PDF) components on peritoneal changes in primary human mesothelial cell. MATERIAL AND METHOD: To investigate the mechanism of changes, primary human peritoneal mesothelial cells (HPMCs) were isolated from human omental tissue and were exposed for 15 hours with the various concentrations of conventional PDF and various PDF components. The mesothelial injury was determined by calculating a ratio of supernatant and total intracellular LDH while mesothelial apoptosis was assessed and counted by positive TUNEL staining and flow cytometry, respectively. RESULTS: PDF caused mesothelial detachment, de-differentiation, cell injuries, and apoptosis and this depended on the concentrations of PDF. The acidic condition and high glucose concentration likely played a major role in the HPMC injuries and detachment while individual PDF component could not yield mesothelial apoptosis as severe as the whole PDF effects. Thus, the additive effects of PDF composition, instead of the effect of each component, contributed to dialysis-related HPMC damages. CONCLUSION: PDF showed concentration dependent fashion-induced HPMC injury, dedifferentiation, and apoptosis. All of the abnormalities occurred by the additive effects of PDF components.