A European multicenter study on the analytical performance of the VERIS HBV assay.

BACKGROUND: Hepatitis B viral load monitoring is an essential part of managing patients with chronic Hepatits B infection. Beckman Coulter has developed the VERIS HBV Assay for use on the fully automated Beckman Coulter DxN VERIS Molecular Diagnostics System.1 OBJECTIVES: To evaluate the analytical performance of the VERIS HBV Assay at multiple European virology laboratories. STUDY DESIGN: Precision, analytical sensitivity, negative sample performance, linearity and performance with major HBV genotypes/subtypes for the VERIS HBV Assay was evaluated. RESULTS: Precision showed an SD of 0.15 log10 IU/mL or less for each level tested. Analytical sensitivity determined by probit analysis was between 6.8-8.0 IU/mL. Clinical specificity on 90 unique patient samples was 100.0%. Performance with 754 negative samples demonstrated 100.0% not detected results, and a carryover study showed no cross contamination. Linearity using clinical samples was shown from 1.23-8.23 log10 IU/mL and the assay detected and showed linearity with major HBV genotypes/subtypes. CONCLUSIONS: The VERIS HBV Assay demonstrated comparable analytical performance to other currently marketed assays for HBV DNA monitoring.

A European multicientre study on the comparison of HBV viral loads between VERIS HBV assay and Roche COBAS® TAQMAN® HBV test, Abbott RealTime HBV assay, Siemens VERSANT HBV assay, and Qiagen artus HBV RG kit.

BACKGROUND: Hepatitis B viral load testing is essential to treatment and monitoring decisions in patients with chronic Hepatitis B. Beckman Coulter has developed the VERIS HBV Assay (Veris) for use on the fully automated DxN VERIS Molecular Diagnostics System.1 OBJECTIVES: To evaluate the clinical performance of the Veris HBV Assay at multiple EU laboratories STUDY DESIGN: Method comparison was performed with a total of 344 plasma specimens from HBV infected patients tested with Veris and COBAS® TaqMan® HBV Test (Cobas), 207 specimens tested with Veris and RealTime HBV Assay (RealTime), 86 specimens tested with Veris and VERSANT® HBV Assay (Versant), and 74 specimens tested with Veris and artus® HBV RG PCR kit (artus). RESULTS: Bland-Altman analysis showed average bias of -0.46 log10 IU/mL between Veris and Cobas, -0.46 log10IU/mL between Veris and RealTime, -0.36 log10IU/mL between Veris and Versant, and -0.12 log10IU/mL between Veris and artus. Bias was consistent across the assay range. Patient monitoring results using Veris demonstrated similar viral load trends over time to Cobas, RealTime, and artus. CONCLUSIONS: The VERIS HBV Assay demonstrated comparable clinical performance, with varying degrees of negative bias, compared to other currently marketed assays for HBV DNA monitoring. This negative bias should be taken into consideration if switching monitoring methods to Veris.

A European multicientre study on the comparison of HIV-1 viral loads between VERIS HIV-1 Assay and Roche COBAS® TAQMAN® HIV-1 test, Abbott RealTime HIV-1 Assay, and Siemens VERSANT HIV-1 Assay.

BACKGROUND: Viral load monitoring is essential for patients under treatment for HIV. Beckman Coulter has developed the VERIS HIV-1 Assay for use on the novel, automated DxN VERIS Molecular Diagnostics System.¥ OBJECTIVES: Evaluation of the clinical performance of the new quantitative VERIS HIV-1 Assay at multiple EU laboratories. STUDY DESIGN: Method comparison with the VERIS HIV-1 Assay was performed with 415 specimens at 5 sites tested with COBAS® AmpliPrep/COBAS® TaqMan® HIV-1 Test, v2.0, 169 specimens at 3 sites tested with RealTime HIV-1 Assay, and 202 specimens from 2 sites tested with VERSANT HIV-1 Assay. Patient monitoring sample results from 4 sites were also compared. RESULTS: Bland-Altman analysis showed the average bias between VERIS HIV-1 Assay and COBAS HIV-1 Test, RealTime HIV-1 Assay, and VERSANT HIV-1 Assay to be 0.28, 0.39, and 0.61 log10 cp/mL, respectively. Bias at low end levels below 1000cp/mL showed predicted bias to be <0.3 log10 cp/mL for VERIS HIV-1 Assay versus COBAS HIV-1 Test and RealTime HIV-1 Assay, and <0.5 log10cp/mL versus VERSANT HIV-1 Assay. Analysis on 174 specimens tested with the 0.175mL volume VERIS HIV-1 Assay and COBAS HIV-1 Test showed average bias of 0.39 log10cp/mL. Patient monitoring results using VERIS HIV-1 Assay demonstrated similar viral load trends over time to all comparators. CONCLUSIONS: The VERIS HIV-1 Assay for use on the DxN VERIS System demonstrated comparable clinical performance to COBAS® HIV-1 Test, RealTime HIV-1 Assay, and VERSANT HIV-1 Assay.

European Multicenter Study on Analytical Performance of Veris HIV-1 Assay.

The analytical performance of the Veris HIV-1 assay for use on the new, fully automated Beckman Coulter DxN Veris molecular diagnostics system was evaluated at 10 European virology laboratories. The precision, analytical sensitivity, performance with negative samples, linearity, and performance with HIV-1 groups/subtypes were evaluated. The precision for the 1-ml assay showed a standard deviation (SD) of 0.14 log10 copies/ml or less and a coefficient of variation (CV) of ≤6.1% for each level tested. The 0.175-ml assay showed an SD of 0.17 log10 copies/ml or less and a CV of ≤5.2% for each level tested. The analytical sensitivities determined by probit analysis were 19.3 copies/ml for the 1-ml assay and 126 copies/ml for the 0.175-ml assay. The performance with 1,357 negative samples demonstrated 99.2% with not detected results. Linearity using patient samples was shown from 1.54 to 6.93 log10 copies/ml. The assay performed well, detecting and showing linearity with all HIV-1 genotypes tested. The Veris HIV-1 assay demonstrated analytical performance comparable to that of currently marketed HIV-1 assays. (DxN Veris products are Conformité Européenne [CE]-marked in vitro diagnostic products. The DxN Veris product line has not been submitted to the U.S. FDA and is not available in the U.S. market. The DxN Veris molecular diagnostics system is also known as the Veris MDx molecular diagnostics system and the Veris MDx system.).

A European multicentre study on the comparison of HCV viral loads between VERIS HCV assay and COBAS® TaqMan® HCV Test and RealTime HCV Assay.

BACKGROUND: Beckman Coulter has developed the VERIS HCV Assay for use on the new fully automated DxN VERIS Molecular Diagnostic System¥ for HCV viral load monitoring. OBJECTIVES: Evaluate the clinical performance of the new quantitative VERIS HCV Assay. STUDY DESIGN: Comparison was performed on 279 plasma specimens from HCV infected patients tested with the VERIS HCV Assay and COBAS® Ampliprep/COBAS® Taqman® HCV Test and 369 specimens tested with the VERIS HCV Assay and RealTime HCV Assay. Patient monitoring sample results from four time points were also compared. RESULTS: The average bias between the VERIS HCV Assay and the COBAS® Ampliprep/COBAS® Taqman® HCV Test was 0.04 log10IU/mL, while between the VERIS HCV Assay and the RealTime HCV Assay average bias was 0.21 log10IU/mL. Bias, however, was not consistent across the measuring range. Analysis at the lower end of quantification levels 50, 100, and 1000IU/mL showed a predicted bias for VERIS HCV Assay versus COBAS® Ampliprep/COBAS® Taqman® HCV Test between -0.42 and -0.22 log10IU/mL and for VERIS HCV Assay versus RealTime HCV Assay between 0.00 and 0.13 log10IU/mL. Patient monitoring of HCV viral load over time demonstrated similar levels between VERIS HCV Assay results and COBAS® Ampliprep/COBAS® Taqman® HCV Test (52 samples from 13 patients) and RealTime HCV Assay (112 samples from 28 patients). CONCLUSIONS: VERIS HCV Assay for use on the DxN VERIS Molecular Diagnostic System represents a reliable new tool for easy sample to result HCV RNA viral load monitoring.

European Multicenter Study on Analytical Performance of DxN Veris System HCV Assay.

The analytical performance of the Veris HCV Assay for use on the new and fully automated Beckman Coulter DxN Veris Molecular Diagnostics System (DxN Veris System) was evaluated at 10 European virology laboratories. Precision, analytical sensitivity, specificity, and performance with negative samples, linearity, and performance with hepatitis C virus (HCV) genotypes were evaluated. Precision for all sites showed a standard deviation (SD) of 0.22 log10 IU/ml or lower for each level tested. Analytical sensitivity determined by probit analysis was between 6.2 and 9.0 IU/ml. Specificity on 94 unique patient samples was 100%, and performance with 1,089 negative samples demonstrated 100% not-detected results. Linearity using patient samples was shown from 1.34 to 6.94 log10 IU/ml. The assay demonstrated linearity upon dilution with all HCV genotypes. The Veris HCV Assay demonstrated an analytical performance comparable to that of currently marketed HCV assays when tested across multiple European sites.

Characterization of resistance mechanisms and genetic relatedness of carbapenem-resistant Acinetobacter baumannii isolated from blood, Italy.

The aim of this study was to characterize the resistance mechanisms and genetic relatedness of 21 carbapenem-resistant Acinetobacter baumannii blood isolates collected in Italy during a 1-year multicenter prospective surveillance study. Genes coding for carbapenemase production were identified by polymerase chain reaction (PCR) and sequencing. Pulsed-field gel electrophoresis (PFGE), multiplex PCRs for group identification, and multilocus sequence typing (MLST) were used to determine genetic relationships. Carbapenem resistance was consistently related to the production of oxacillinases, mostly the plasmid-mediated OXA-58 enzyme. Strains producing the OXA-23 enzyme (chromosomally mediated) were also detected. Seven PFGE clones were identified, some of which being related to international (ICL- I and ICL-II) or national clonal lineages. Multiplex PCRs identified 4 different groups (group 2 being dominant), further distinguishable in 6 sequence types by MLST. The heterogeneity of profiles highlights the diffusion of international and national clonal lineages in Italy. Continuous surveillance is needed for monitoring the spread of these worrisome strains equipped with multiple drug resistance mechanisms.

Prevalence and epidemiology of microbial pathogens causing bloodstream infections: results of the OASIS multicenter study.

Beginning on April 2007, a prospective multicenter study was performed to investigate prevalence and epidemiology of microbial pathogens causing bloodstream infections (BSIs). Twenty microbiology laboratories participated to the survey over a 1-year period. A total of 11,638 episodes of BSI occurred in 11 202 patients, with 8.5% (n=985) of episodes being polymicrobial. Of 12 781 causative organisms, aerobic Gram-negative bacteria were 47.4% (n=6058), whereas Gram-positives accounted for 43.9% (n=5608). The remaining organisms included fungal species (n=924, 7.2%) and anaerobes (n=191, 1.5%). The most prevalent agents were Escherichia coli (21.7%), Staphylococcus aureus (14.9%), Staphylococcus epidermidis (8.2%), Pseudomonas aeruginosa (7.0%), and Enterococcus faecalis (6.3%). Isolates recovered from patients admitted to medical, surgical, and intensive care units accounted for 62.9%, 17.7%, and 19.4% of cases, respectively. BSIs were classified as hospital-acquired in 67.2% of cases. Compared with previous studies, our data show an increasing role of Gram-negative bacteria among both hospital- and community-acquired blood isolates.

Surface localization of glucosylceramide during Cryptococcus neoformans infection allows targeting as a potential antifungal.

Cryptococcus neoformans (Cn) is a significant human pathogen that, despite current treatments, continues to have a high morbidity rate especially in sub-Saharan Africa. The need for more tolerable and specific therapies has been clearly shown. In the search for novel drug targets, the gene for glucosylceramide synthase (GCS1) was deleted in Cn, resulting in a strain (Δgcs1) that does not produce glucosylceramide (GlcCer) and is avirulent in mouse models of infection. To understand the biology behind the connection between virulence and GlcCer, the production and localization of GlcCer must be characterized in conditions that are prohibitive to the growth of Δgcs1 (neutral pH and high CO(2)). These prohibitive conditions are physiologically similar to those found in the extracellular spaces of the lung during infection. Here, using immunofluorescence, we have shown that GlcCer localization to the cell surface is significantly increased during growth in these conditions and during infection. We further seek to exploit this localization by treatment with Cerezyme (Cz), a recombinant enzyme that metabolizes GlcCer, as a potential treatment for Cn. Cz treatment was found to reduce the amount of GlcCer in vitro, in cultures, and in Cn cells inhabiting the mouse lung. Treatment with Cz induced a membrane integrity defect in wild type Cn cells similar to Δgcs1. Cz treatment also reduced the in vitro growth of Cn in a dose and condition dependent manner. Finally, Cz treatment was shown to have a protective effect on survival in mice infected with Cn. Taken together, these studies have established the legitimacy of targeting the GlcCer and other related sphingolipid systems in the development of novel therapeutics.