Molecular characterization and diagnosis of nosocomial clostridium difficile infection in hospitalized patients

Background: Toxigenic Clostridium difficile is one of the prevalent diarrheagenic pathogens in hospitalized patients. Objectives: The study assessed the ability of three diagnostic methods in identifying C. difficile strains. The genotyping of the isolates was done, as well. Methods: Stool samples were subjected to three different diagnostic methods including direct stool culture, glutamate dehydroge-nase enzyme immunoassay (GDH-EIA), and direct stool PCR for the detection of the tcdA and tcdB genes. The sensitivity and specificity of the tests were evaluated. The genotyping was done by the PFGE method. Results: Of 120 samples, 20 (16) were positive for C. difficile based on PCR, while 15 (12.5) and 12 (10) were positive according to GDH-EIA and direct stool culture. Among patients with C. difficile-associated diseases (CDAD), 11 (61) were more than 65-years-old. The specificity of PCR, GDH-EIA, and direct culture was almost similar and equal to 100, but their sensitivity was 90, 70, and 60, respectively. The positive predictive value (PPV) was lower for GDH-EIA than for the other two methods, and the highest negative predictive value (NPV) was related to the PCR method. The results showed a high similarity between the isolates, and only were three pulsotypes differentiated among the isolates. Conclusions: The specificity and sensitivity of the direct stool PCR method were higher than those of the other two methods. Al-though PCR inhibitors may reduce its ability for the correct diagnosis of negative samples, it seems to be a reliable method for the detection of C. difficile infection. The weakness of the GDH-EIA method was its lower PPV, which can cause false-positive results. Toxin patterns and pulsotypes of C. difficile isolates revealed a high similarity between the strains isolated from the same units. © 2020, Author(s)

Quality of life after islet transplant: impact of the number of islet infusions and metabolic outcome

The health-related quality of life (HRQL; Health Utilities Index Mark 2) and the fear of hypoglycemia (Hypoglycemia Fear Survey) were assessed after islet transplant; the impact of a single islet infusion and of the metabolic outcome were determined. A control group included 166 patients with type 1 diabetes. Islet transplant had no impact on overall HRQL. Prior to transplant, islet recipients had more fear of hypoglycemia than controls (P<0.000001), but this improved up to 36 months after transplant (P<0.00001, pretransplant vs. each time point). With a single islet infusion, this fear improved substantially (P<0.00001), but improved further with subsequent islet infusions (P</=0.01). Fear of hypoglycemia correlated with the occurrence of hypoglycemia (r=0.47, P=0.01), and even more so with blood glucose stability (r=0.56, P=0.0007) and insulin requirement (r=0.69, P=0.000002)

Supplemental islet infusions restore insulin independence after graft dysfunction in islet transplant recipients

BACKGROUND: The ability of supplemental islet infusions (SII) to restore insulin independence in islet transplant recipients with graft dysfunction has been attributed to the coadministration of exenatide. However, improving islet transplant outcomes could explain the success of SII. We aimed to determine the effect on islet graft function and insulin independence of SII using these new protocols, without the use of exenatide. METHODS: Seventeen islet transplant recipients underwent SIIs after developing graft dysfunction requiring insulin use. For induction therapy, four subjects received daclizumab induction therapy, whereas 13 subjects received thymoglobulin and etanercept. Maintenance immunosuppression consisted of sirolimus+tacrolimus or tacrolimus+cellcept. RESULTS: SII was performed 49.3+/-4.8 months (mean+/-SEM) after the preceding islet transplant. Subjects received significantly lower islet mass with their SII compared with initial transplant(s) (6076+/-492 vs. 9071+/-796 IEQ/kg; P=0.003). Fifteen of the 17 subjects (88.2%) became insulin independent 2.4+/-0.5 months after SII. Insulin-independent duration after SII exceeded that of the initial transplant(s) (24.8+/-2.2 vs. 14.2+/-2.6 months by Kaplan-Meier analysis, P=0.009). Subjects show improved glycemic control after SII (HbA1c 7.0%+/-0.2% pre-SII vs. 6.1%+/-0.2% post-SII, P=0.005) and did not become immunosensitized. CONCLUSION: Using current protocols, SII in the absence of exenatide results in impressive insulin-independence rates and the durability of insulin independence seems to be promising. However, a beneficial effect of exenatide should not be discounted until tested in randomized controlled studies

Effect of different induction strategies on effector, regulatory and memory lymphocyte sub-populations in clinical islet transplantation

This prospective study assessed lymphocyte subsets in the peripheral blood of 42 islet allograft recipients using flow cytometry from 2 weeks and up to 2 years post-transplantation. Subjects received daclizumab (n = 16), Thymoglobulin (n = 12) or alemtuzumab (n = 14). Alemtuzumab was associated with an early (within 1 month) and transient (up to 6 months) increase in the frequency of CD3(+) CD4(+) Foxp3(+) T cells, while daclizumab induced a near complete loss of these cells (P ≤ 0.001). The frequency of memory CD4(+) T cells was increased following depleting immunosuppression induction with either Thymoglobulin or alemtuzumab (P ≤ 0.05), but remained unchanged while using daclizumab. Alemtuzumab induction resulted in a significant loss of memory B lymphocytes when compared with the other induction groups (P ≤ 0.001). While the clinical significance of these findings remains to be fully determined, the observed altered balance between effector, regulatory and memory cells suggests that the immune status of patients will be affected according to the induction strategy chosen

Histologic graft assessment after clinical islet transplantation

BACKGROUND: An accurate monitoring would help understanding the fate of islet grafts after transplantation. METHODS: This work assessed the feasibility of needle biopsy monitoring after intraportal islet transplantation (n=16), and islet graft morphology was studied with the addition of autopsy samples (n=2). Pancreas autopsy samples from two nondiabetic individuals were used as control. RESULTS: Islet tissue was found in five needle samples (31%). Sampling success was related to size (100% sampling for the four biopsies of 1.8 cm in length or higher, P ≤ 0.01). Mild liver abnormalities included localized steatosis (n=8), mild nodular regenerative hyperplasia and mild portal venopathy (n=3), and hepatocyte swelling (n=2). Endocrine cell composition and distribution were similar between islet grafts and normal islets within the native pancreas. There was no or minimal immune cell infiltrate in patients on and off exogenous insulin, including two patients with ongoing negative metabolic events (increasing HbA1c or insulin requirement). The infiltrate was mainly composed of CD4- and CD8-positive cells. CONCLUSION: This study demonstrates that needle biopsy is feasible after clinical islet transplantation but with a limited practical value because of its low islet sampling rate using current sampling and analysis methods. Both biopsy and autopsy samples demonstrated the well-preserved islet endocrine composition after transplantation and the presence of focal areas of steatosis. Islet grafts showed no or minimal immune cell infiltration, even in the case of ongoing islet loss. On the basis of the findings, possible reasons for allograft islet loss are discussed

Insulin-heparin infusions peritransplant substantially improve single-donor clinical islet transplant success

BACKGROUND: Successful islet transplantation can result in insulin independence in many patients with type 1 diabetes mellitus, but it often requires more than one islet infusion. The ability to achieve insulin independence with a single donor is an important goal in clinical islet transplantation due to the limited organ supply. METHODS: We examined factors that may be associated with insulin independence after islet transplantation with islets from a single donor, using univariate and multivariate analysis. RESULTS: Thirteen of 85 (15.3%) achieved insulin independence after single-donor islet transplantation. Using multivariate analysis, only the use of insulin and heparin infusions peritransplant was a significant factor associated with insulin independence, with an adjusted odds ratio of 8.6 (95% confidence interval 2.0-37.0). Patients who had received insulin and heparin infusions peritransplant had greater indices of islet engraftment and a greater reduction in insulin use (80.1% + or - 4.3% vs. 54.2% + or - 2.8%, P<0.001) even if insulin independence was not achieved. CONCLUSIONS: Peritransplant intensive insulin and heparin enhances islet transplantation outcomes likely related in part to mitigation of the effects of the instant blood-mediated inflammatory reaction, combined with islet rest and avoidance of inflammation. It would be important to further investigate the effects of peritransplant insulin and heparin infusions on islet engraftment

Three-dimensional curvy electronics created using conformal additive stamp printing

Electronic devices are typically manufactured in planar layouts, but many emerging applications, from optoelectronics to wearables, require three-dimensional curvy structures. However, the fabrication of such structures has proved challenging due, in particular, to the lack of an effective manufacturing technology. Here, we show that conformal additive stamp (CAS) printing technology can be used to reliably manufacture three-dimensional curvy electronics. CAS printing employs a pneumatically inflated elastomeric balloon as a conformal stamping medium to pick up pre-fabricated electronic devices and print them onto curvy surfaces. To illustrate the capabilities of the approach, we use it to create various devices with curvy shapes: silicon pellets, photodetector arrays, electrically small antennas, hemispherical solar cells and smart contact lenses. We also show that CAS printing can be used to print onto arbitrary three-dimensional surfaces

Scientific Reports

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