An unusual outbreak of parvovirus B19 infections, France, 2023 to 2024.

From April 2023 to May 2024, an unusual epidemic of parvovirus B19 (B19V) infections occurred in France. The number of B19V IgM-positive serologies was four times higher than in the previous epidemic in 2019. Clinical data from emergency networks corroborated this observation. Morbidity and mortality consequences were observed in children through all data sources. In adults, the increase was only observed in laboratory-confirmed data. Physicians and decisionmakers should be informed in order to better prevent, diagnose and manage at-risk patients.

Characterization of Samples Identified as Hepatitis C Virus Genotype 1 without Subtype by Abbott RealTime HCV Genotype II Assay Using the New Abbott HCV Genotype Plus RUO Test.

Hepatitis C virus (HCV) genotyping continues to be relevant for therapeutic strategies. Some samples are reported as genotype 1 (gt 1) without subtype by the Abbott RealTime HCV Genotype II (GT II) test. To characterize such samples further, the Abbott HCV Genotype Plus RUO (Plus) assay, which targets the core region for gt 1a, gt 1b, and gt 6 detection, was evaluated as a reflex test in reference to NS5B or 5'-untranslated region (UTR)/core region sequencing. Of 3,626 routine samples, results of gt 1 without subtype were received for 171 samples (4.7%), accounting for 11.5% of gt 1 specimens. The Plus assay and sequencing were applied to 98 of those samples. NS5B or 5'-UTR/core region sequencing was successful for 91/98 specimens (92.9%). Plus assay and sequencing results were concordant for 87.9% of specimens (80/91 samples). Sequencing confirmed Plus assay results for 82.6%, 85.7%, 100%, and 89.3% of gt 1a, gt 1b, gt 6, and non-gt 1a/1b/6 results, respectively. Notably, 12 gt 6 samples that had been identified previously as gt 1 without subtype were assigned correctly here; for 25/28 samples reported as "not detected" by the Plus assay, sequencing identified the samples as gt 1 with subtypes other than 1a/1b. The genetic variability of HCV continues to present challenges for the current genotyping platforms regardless of the applied methodology. Samples identified by the GT II assay as gt 1 without subtype can be further resolved and reliably characterized by the new Plus assay.

A multicenter assessment of the analytical performance of the routine thyroid panel on the Olympus AU3000i immunoassay system.

BACKGROUND: The AU3000i thyroid assay panel (TSH, fT4, T4, fT3, T3) was evaluated at four sites in a European multicenter study. The study was designed to assess the basic analytical performance characteristics of the Olympus thyroid assays. In addition, a comprehensive assessment of the TSH functional sensitivity was undertaken to challenge the manufacturer's claim of 4th generation assay performance. RESULTS: Repeatability (within-run precision) of TSH, ff4 and T4 was better than 3% across the measurable range, T3 and fT3 repeatability was better than 6%. Within-laboratory (total) precision was better than 10% for all assays, for fT4, it was better than 3%. Method comparisons were undertaken against the Roche Elecsys 2010, the Siemens Advia Centaur and the Abbott Architect. Overall, good to excellent correlations were seen, however in some cases there were systematic differences which can be attributed to the lack of an appropriate standard or reference method and/or heterogeneity of the analyte. The functional sensitivity of the Olympus TSH assay was confirmed to be 4th generation, giving a mean functional sensitivity (at 20% CV) of 0.0011 mIU/L with no sites exceeding 0.002 mIU/L. Plasma (Li-heparinate) was shown to be an acceptable sample type for use in these assays. CONCLUSION: The results generated in this study indicate that the assays of the Olympus AU3000i routine thyroid panel are precise, correlate well with other established assays, and are suitable for use in the routine clinical laboratory.

Multicenter evaluation of workflow performances of the new Olympus AU3000i.

BACKGROUND: A new immunoanalyzer (AU3000i) has been developed by Olympus (Rungis, France) with the intention of offering a consolidated workcell. The aim of this experiment was to assess, in a multi-centre study (two French sites, one German site), the practicability of the Olympus AU3000i in terms of throughput (test/h), rerun capabilities, emergency sample handling and reflex test capabilities. RESULTS: The workload study showed that the AU3000i was capable of running both one- and two-step assay protocols with a throughput of 240 tests per hour which corresponds to 209.3 tests per hour including the initialization time. Emergency samples were correctly treated as a priority in less than 30 minutes for ten samples. Furthermore the analyzer could be programmed to generate automatic dilution, rerun and reflex tests, reducing the hands-on labour time for technicians. CONCLUSION: Workflow studies showed that Olympus AU3000i and AU Clinical Chemistry can cover the combined workload of various routine analyzers in a variety of laboratory environments.

Could the new HIV combined p24 antigen and antibody assays replace p24 antigen specific assays?

The performance of twelve HIV combined p24 antigen and antibody assays available in Europe were compared. The assays were examined with a total of 1983 samples that included 1005 unselected HIV negative samples, 7 HIV-1 p24 Ag reference samples with HIV-1 Ag, 10 samples of a HIV antigen sensitivity commercial panel, 124 samples of 31 p24 antigen panels of different HIV-1 subtypes, 168 members of 24 HIV-1 seroconversion panels, 559 HIV-1 (groups M and O) antibody positive samples and 110 HIV-2 antibody positive samples. The specificity ranged from 99.4 to 100%. Ten of the 12 assays detected all anti-HIV positive samples irrespective of genotype while two assays missed one sample each (one subtype F and one subtype C). The combined assays could be classified into three groups. The first includes two assays (Enzygnost HIV Integral and Vironostika Ag/Ab) that have a clinical sensitivity similar to the two antibody only assays. The second includes the seven assays that detected infection after the p24 antigen only assay and show a delay from 3.3 to 5.17 days after HIV-1 RNA. The third group detected the infection before the p24 antigen assay and less than 3 days after nucleic acid testing (NAT). The improved ability to detect p24 Ag, at levels similar to specific HIV Ag assays, suggests that these new HIV combined Ag/Ab assays could replace p24 antigen only assays in situations for blood or organ screening when NAT is not feasible or not affordable.

Sensitivities of four new commercial hepatitis B virus surface antigen (HBsAg) assays in detection of HBsAg mutant forms.

Mutations in hepatitis B virus surface antigen (HBsAg) involving amino acid substitution within the immunodominant "a" determinant may affect the performance of commercial HBsAg assays. The performances of four HBsAg assays that recently received Conformité Européene marking, Advia Centaur HBsAg (Bayer), Monolisa HBsAg Ultra (Bio-Rad), Liaison HBsAg (Dia Sorin), and Vidas HBsAg Ultra (bioMérieux), were compared with that of the routinely used HBsAg assay AxSYM HBsAg V2 (Abbott). Assays were evaluated for (i) analytical sensitivity performance with a national reference HBsAg panel (including 10 samples with calibrated HBsAg concentrations from 0.04 to 2.24 ng/ml) and (ii) the detection of HBsAg mutants by studying a panel of 35 HBsAg mutants (23 collected from patients and 12 recombinant mutants). The limits of detection of these assays were <0.15 ng/ml (from 0.089 to 0.121 ng/ml). The sensitivity performances for mutant virus detection varied, ranging from 37.1% to 91.4%. The lack of detection of these mutants by commercial assays was probably due to the epitope recognition of the anti-HBs assay reagents in the capture phase and in the conjugates. The prevalence and clinical impact of HBsAg mutants are under investigation. However, the manufacturers must be vigilant in the design of the assays in order to reduce the risk of missing a broad range of described S gene mutants.

An observational study of upper gastrointestinal bleeding in intensive care units: is Helicobacter pylori the culprit?

OBJECTIVE: Upper gastrointestinal bleeding (UGIB) related to stress ulcers was formerly a fearsome complication of intensive care. The incidence of this event has decreased over the years. However, the morbidity, mortality, and causes of UGIB, particularly the etiologic role of Helicobacter pylori infection, are still controversial. Therefore, we prospectively assessed the incidence of UGIB in the intensive care unit (ICU) and evaluated the role of H. pylori infection. DESIGN: A prospective observational study followed by a case-control study. SETTING: Seven ICUs in the Paris area, five of them located in teaching hospitals. PATIENTS: All patients admitted consecutively to seven ICUs during a 1-year period were monitored for signs of clinically relevant UGIB. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Only cases of endoscopically confirmed UGIB were analyzed. Patients whose hemorrhage originated from the stomach and/or duodenum were tested for H. pylori infection, by means of serology, histologic examination, and stool antigen detection. The possible association between H. pylori and UGIB was examined in a case-control study. Twenty-nine of the 4,341 patients admitted to the seven ICUs during the study period had clinically relevant, endoscopically confirmed UGIB (incidence, 0.67%; 95% confidence interval, 0.56%-0.77%). Ulcers were most frequently observed endoscopically. Patients who bled had a higher Simplified Acute Physiology Score (SAPS II) at admission (mean +/- sd, 47 +/- 14 vs. 36 +/- 28; p < .001). Despite a higher in-ICU mortality rate among patients who bled (73% vs. 16%; p < .001), death was never due to bleeding. H. pylori infection was more frequent in patients who bled than in matched controls (36% vs. 16%; p = .04). CONCLUSIONS: Clinically relevant, endoscopically confirmed UGIB is a rare event in the ICU setting and tends to occur in severely ill patients. H. pylori infection is more frequent in patients with gastroduodenal hemorrhage than in nonbleeding patients.

Evaluation of the sensitivity and specificity of six HIV combined p24 antigen and antibody assays.

In this study, we evaluated the performance of six HIV combined p24 antigen and antibody (Ag/Ab) assays versus two third-generation anti-HIV antibody assays. The assays were evaluated using p24 antigen panel of 31 HIV-1 subtypes (n = 124), 25 HIV-1 seroconversion panels (n = 176), HIV-1 antibody positive samples including group M subtypes and group O (n = 559), HIV-2 positive samples (n = 110), and unselected HIV negative samples from four French private laboratories (n = 1005). The results showed that overall HIV combined Ag/Ab assays present better performance, when compared to antibody-only assays. However, some differences were observed in the sensitivity of the six HIV combined Ag/Ab assays evaluated. The AxSYM and Murex Combo assays had the best sensitivity score in this study and reduced the window period by 2.0-2.35 days relative to antibody only assays and 1-2.17 days relative to the other combined Ag/Ab assays. Among combined HIV Ag/Ab assays, Genscreen Plus and AxSYM Combo presented the highest specificity, with 99.9% and 99.8%, respectively.

Treatment of latent syphilis in HIV-infected patients with 10 d of benzylpenicillin G benethamine: a prospective study in Maputo, Mozambique.

Neurosyphilis has been reported in HIV-infected patients previously treated with penicillin G benzathine, which does not achieve treponemicidal levels in cerebrospinal fluid. Therapy combining benzylpenicillin G and its repository form benzylpenicillin G benethamine could be a potentially effective alternative enhanced regimen for treating latent syphilis in HIV-infected patients because peak serum and cerebrospinal fluid concentrations would be achieved early post-administration by the former molecule and sustained for 24 h due to the prolonged half-life of the latter. In this study, 23 asymptomatic HIV and Treponema pallidum co-infected patients received 10 d of combined therapy (2 M IU intramuscular once daily) and were followed up at 3, 6 and 12 months. None experienced side effects or clinical symptoms. Of the 18 patients who were evaluated 1 y later, 8 (44.4%) exhibited serological treatment failure, defined as a positive serum rapid plasma reagin test. In conclusion, a 10-d regimen combining penicillin G and penicillin G benethamine seems to be of no benefit compared to currently recommended treatment.