Increase in Hospital Admissions for Severe Influenza A/B among Travelers on Cruise Ships to Alaska, 2015.

An increase in hospital admissions for influenza occurred during the summer of 2015 at an acute care facility in Vancouver, British Columbia, Canada. Investigation identified 25 patients with recent history of cruise ship travel to Alaska. All characterized influenza A viruses were A(H3N2). We describe patient treatment regimens and outcomes.

Transitioning cytomegalovirus viral load testing from a laboratory developed test to the cobas® CMV quantitative nucleic acid assay.

Commutability between human cytomegalovirus (CMV) viral load assays (VLA) is poor, despite the development of a WHO CMV International Standard (CMV IS). We evaluated a new CMV VLA, cobas® CMV, as compared to our current laboratory developed CMV VLA (LDT), for clinical use. Both the LDT and cobas® CMV were run in parallel for 109 patient samples. In addition, 104 replicates, over 8 dilutions, of the CMV IS were tested. Conversion factors and correlation between the two assays were calculated. The correlation coefficient between the LDT and cobas® CMV was 0.91 for patient samples. The Bland-Altman graph displayed a systematic bias of +0.31 log10 for the cobas® CMV as compared to the LDT. The bias was greater for lower CMV viral loads. This increase in CMV viral loads was not seen with testing of the CMV IS dilutions by both the LDT and cobas® CMV. CMV VLA inter-assay commutability continues to be an issue when switching CMV testing platforms and requires communication between the laboratory and clinicians during the transition period to prevent misinterpretation of results.

HIV serology signal-to-cutoff ratio as a rapid method to predict confirmation of HIV infection.

Early and rapid detection of patients with HIV is a key to preventing further transmission. The purpose of this study was to assess the ability of signal-to-cutoff (S/CO) ratio from initial screening fourth-generation HIV serology to predict subsequent confirmation of HIV. Patients with a first-time positive HIV serology (S/CO ratio ≥ 1) from 2012 to 2016 were included. Ratios were compared to the results of confirmatory testing. Predictive probabilities (PPs) of a positive confirmatory result were calculated based on a logistic regression model. A total of 45,138 HIV serology tests were performed; 250 patients met inclusion criteria, comprising 84 (34%) HIV negative patients, 136 (54%) chronic infections, and 30 (12%) acute infections. The PP of a confirmed positive result increased with higher S/CO ratios, with a PP of 100% for a S/CO of 55 (95% CI 95-100). This study enables a more informed discussion of the probability of HIV infection, based on HIV serology S/CO thresholds, prior to a confirmatory result.

Implementation of Next-Generation Sequencing for Hepatitis B Virus Resistance Testing and Genotyping in a Clinical Microbiology Laboratory.

Sanger sequencing or DNA hybridization have been the primary modalities for hepatitis B (HBV) resistance testing and genotyping; however, there are limitations, such as low sensitivity and the inability to detect novel mutations. Next-generation sequencing (NGS) for HBV can overcome these limitations, but there is limited guidance for clinical microbiology laboratories to validate this novel technology. In this study, we describe an approach to implementing deep pyrosequencing for HBV resistance testing and genotyping in a clinical virology laboratory. A nested PCR targeting the pol region of HBV (codons 143 to 281) was developed, and the PCR product was sequenced by the 454 Junior (Roche). Interpretation was performed by ABL TherapyEdge based on European Association for the Study of the Liver (EASL) guidelines. Previously characterized HBV samples by INNO-LiPA (LiPA) were compared to NGS with discordant results arbitrated by Sanger sequencing. Genotyping of 105 distinct samples revealed a concordance of 95.2% (100/105), with Sanger sequencing confirming the NGS result. Resistance testing by NGS was concordant with LiPA in 85% (68/80) of previously characterized samples. Additional mutations were found in 8 samples, which related to the identification of low-level mutant subpopulations present at <10% (6/8). To balance the costs of testing for the validation study, reproducibility of the NGS was investigated through an analysis of sequence variants at loci not associated with resistance in a single patient sample. Our validation approach attempts to balance costs with efficient data acquisition.

Evaluating Inflammatory Versus Mechanical Back Pain in Individuals with Psoriatic Arthritis: A Review of the Literature.

Psoriatic arthritis (PsA) is a chronic immune-mediated disease characterized by psoriatic skin and nail changes, peripheral joint inflammation, enthesitis, dactylitis, and/or axial involvement, either alone or in combination with each other. The presence of axial involvement has been shown to be a marker of PsA severity; however, there is no widely accepted definition of axial involvement in PsA (axPsA) or consensus on how or when to screen and treat patients with suspected axPsA. Chronic back pain is a prominent feature of axPsA and is thought to have a relevant role in early identification of disease. Chronic back pain can be caused by inflammatory back pain (IBP) or mechanical back pain (MBP). However, MBP can complicate recognition of IBP and delay diagnosis of axPsA. While MBP can also be associated with chronic back pain of ≥ 3 months in duration that is typical of IBP, IBP is characterized by inflammation of the sacroiliac joint and lower spine that is differentiated from MBP by key characteristic features, including insidious onset at age < 40 years, improvement with exercise but not with rest, and nighttime pain. This review discusses the differences in identification and management of IBP and MBP in patients with PsA with axPsA. The summary of available evidence highlights the importance of appropriate and timely screening, difficulties and limitations of differential diagnoses and treatment, and unmet needs in axPsA.

Psoriatic arthritis (PsA) is a long-term disease that may lead to psoriatic changes in skin and nails; inflammation of some joints, including finger and toe joints (dactylitis); inflammation of sites where tendons and ligaments connect to bone (enthesitis); and/or problems in the spine (axial involvement). Approximately 25­70% of patients with PsA have axial involvement (axPsA); this number varies because there is no widely accepted definition for axPsA. Chronic (long-lasting) back pain is a major feature of axSpA and can help doctors recognize axPsA early. Chronic back pain can be caused by inflammatory back pain (IBP) or mechanical back pain (MBP). IBP is described by back pain lasting ≥ 3 months, gradual onset at age < 40 years, improvement with exercise, no improvement with rest, pain at night (with improvement upon getting up), and changes in some laboratory test results. On the other hand, MBP is caused by a physical injury to the lower back. Both IBP and MBP can occur in patients with PsA, but they are treated in different ways. Being able to tell the difference between IBP and MBP is important to make sure that patients receive the right treatment. This review looks at the differences between IBP and MBP, screening for IBP, the difficulties and limitations of diagnosing and treating axPsA, and the needs of patients with axPsA for better diagnosis and treatment.

Comprehensive comparison of the VERSANT HIV-1 RNA 3.0 (bDNA) and COBAS AMPLICOR HIV-1 MONITOR 1.5 assays on 1,000 clinical specimens.

BACKGROUND: Plasma human immunodeficiency virus type 1 (HIV-1) RNA level is an important parameter for patient management, yet viral load assays from different manufacturers are not standardized. OBJECTIVES AND STUDY DESIGN: In this study, we evaluated the concordance between test results obtained for 1,000 plasma specimens collected from HIV-1-infected individuals measured with the VERSANT HIV-1 RNA 3.0 assay (bDNA) and the COBAS AMPLICOR HIV-1 MONITOR 1.5 test (PCR). We compared viral load values obtained by each of these assays throughout their dynamic ranges, with particular focus on samples with low viral load (i.e. 50-250 copies/mL), and calculated the estimated distribution of distinct plasma viral load levels for the entire study population modeled from the data observed in the study. RESULTS: We found that these two assays show excellent agreement, with a correlation (R(2)) of 0.957 and a slope of 1.004. The mean difference in viral load values between the two assays was less than 0.10-log(10) throughout the dynamic range and 98.2% of all samples had bDNA and PCR results within 0.5-log(10) of each other, a difference that is within the range considered to be a minimal change in plasma viremia. Moreover, the two assays show very similar results across all assay ranges tested. The estimated prevalence of samples with results <50 copies/mL, 50-250 copies/mL, and 250-500,000 copies/mL were 41.6%, 7.7%, and 49.7%, respectively, by the bDNA assay, and 42.4%, 6.9%, and 50.7%, respectively, by the PCR assay. CONCLUSION: Based on our findings from 1,000 clinical specimens, we do not see the need to re-establish a baseline value or apply a conversion factor when switching from one assay to the other. Since the majority of our patient population likely is infected with subtype B virus, it is unclear if our findings will apply to other patient populations with a greater incidence of infection with non-B subtypes.

Use of Sno Strip filter-paper wicks for collection of genital-tract samples allows reproducible determination of human immunodeficiency virus type 1 (HIV-1) RNA viral load with a commercial HIV-1 viral load assay.

To assess the reproducibility of measurements of cervical and vaginal human immunodeficiency virus (HIV) viral load, 92 duplicate cervical and 88 duplicate vaginal samples were collected from 13 HIV-infected women using Sno Strip filter-paper wicks. RNA was eluted from the strips, extracted, and assayed using a modified protocol for the Roche Cobas Amplicor HIV-1 Monitor assay. Pearson's correlation coefficient (R), coefficient of determination (D), and Bland-Altman plots (BA) were used to compare paired log10-transformed viral loads. Analysis of duplicate same-site samples showed good reproducibility (cervix: R = 0.72, D = 52%, BA = 89% within range; vagina: R = 0.72, D = 51%, BA = 87% within range); paired cervix/vagina measurements showed moderate correlation only (R = 0.56; D = 31.3%). Standardized sample collection and simple modification of the Roche Cobas Amplicor HIV-1 Monitor assay allows reproducible measurement of genital viral load.

Multicenter evaluation of the VERSANT hepatitis B virus DNA 3.0 assay.

The VERSANT hepatitis B virus (HBV) 3.0 Assay (branched DNA [bDNA]) (referred to herein as VERSANT 3.0) was evaluated at four external sites for analytical sensitivity, specificity, reproducibility, linearity of quantification, and limits of detection. In addition, each of the test evaluation sites provided HBV DNA-positive clinical samples that were previously analyzed by one of three commercially available HBV DNA quantitative tests: Digene Hybrid Capture II HBV DNA Test (Digene); VERSANT HBV DNA 1.0 Assay (bDNA) (VERSANT 1.0); and COBAS AMPLICOR HBV Monitor Test (COBAS AMPLICOR). These samples were reexamined using VERSANT 3.0. The results from these studies showed that VERSANT 3.0 has high specificity (99.3%), excellent reproducibility (between-run coefficient of variation [CV] = 1.6 to 9.4%; within-run CV = 6.5 to 20.7%), and a broad linear range of quantification (2.0 x 10(3) to 1.0 x 10(8) HBV DNA copies/ml) that facilitate the monitoring of HBV DNA levels at diagnosis and throughout the course of treatment. In general, correlation was very good between results obtained from clinical samples analyzed by VERSANT 3.0 and the comparative HBV DNA quantitative assays (VERSANT 1.0, R(2) = 0.900; Digene, R(2) = 0.985; COBAS AMPLICOR, R(2) = 0.771). The greatest differences in comparative quantitation occurred at HBV DNA levels approaching the limits of the dynamic ranges for the comparative assays. The performance characteristics of the new VERSANT 3.0 assay demonstrated that it provides a reliable and robust method for routinely monitoring serum HBV DNA levels in assessing disease activity and determining response to antiviral treatment.