Evaluation of the sample-to-result, random access NeuMoDx platform for viral load testing of Cytomegalovirus and Epstein Barr virus in clinical specimens.

BACKGROUND: The detection and follow up of cytomegalovirus (CMV) and Epstein-Barr virus (EBV) viral loads (VL) are crucial in the management of immunocompromised patients. Recently, molecular CE-IVD assays for detection and quantification of CMV and EBV have been launched for use on the random-access and sample-to-result NeuMoDx 96 and 288 platforms (Qiagen). OBJECTIVE: Evaluating the qualitative and quantitative performance of the NeuMoDx CMV and EBV assays in clinical specimens compared to a lab developed tests (LDT) and the CE-IVD assays on the Abbott m2000 system. METHOD: Both a prospective and a retrospective panel, compiled of non-detectable (ND), non-quantifiable (NQ) and quantifiable VLs in plasma samples have been evaluated for both CMV and EBV: NeuMoDx versus LDT and NeuMoDx versus Abbott m2000. Quantitative agreement was determined for samples with a quantifiable VL on both systems. RESULTS: Qualitative and quantitative agreement between the NeuMoDx and LUMC's LDT CMV assays was 88%. Qualitative agreement between the NeuMoDx and Abbott m2000 CMV assays was 92% and quantitative agreement was 87%. Qualitative and quantitative agreement between the NeuMoDx and the LDT EBV assays was 87%. Qualitative agreement between the NeuMoDx and Abbott m2000 EBV assays was 91% and quantitative agreement was 0%. CONCLUSION: These data show that the NeuMoDx assays are suitable for both detection and quantification of CMV and EBV in a medium- to high throughput diagnostic setting, but that differences in sensitivity and quantification (for EBV, NeuMoDx versus Abbott m2000) warrant an extensive transition period when using the respective assays for following VL in patient samples.

Norovirus disease associated with excess mortality and use of statins: a retrospective cohort study of an outbreak following a pilgrimage to Lourdes.

Although norovirus infection is generally known to be a mild disease, there is some evidence for severe outcome. An outbreak in a Dutch psychiatric institution, originating from pilgrims returning from Lourdes (France), provided an opportunity for performing a retrospective cohort study in order to identify risk factors for norovirus disease and excess mortality. Relative risks (RR) including 95% confidence intervals (CI) showed that attending the pilgrimage (RR 2·0, 95% CI 1·4-3·0) and age >70 (RR 1·7, 95% CI 1·2-2·2) were risk factors for symptomatic infection. In a subset of patients, for whom more detailed information was available, the use of statins was associated with norovirus disease when adjusted for underlying condition (adjusted odds ratio 3·9, 95% CI 1·2-13·0). Mortality was higher in cases infected during the pilgrimage compared to other residents (RR 20·9, 95% CI 4·7-93·8). Norovirus disease can lead to severe outcome. The newly identified risk of statins for contracting norovirus disease may have considerable consequences for the Western world and needs prospective confirmation.

Clostridium difficile is not associated with outbreaks of viral gastroenteritis in the elderly in the Netherlands.

The coincidental increase in norovirus outbreaks and Clostridium difficile infection (CDI) raised the question of whether these events could be related, e.g. by enhancing spread by diarrhoeal disease outbreaks. Therefore, we studied the prevalence of C. difficile in outbreaks of viral gastroenteritis in nursing homes for the elderly and characterised enzyme immunoassay (EIA)-positive stool samples. Stool samples from nursing home residents (n = 752) in 137 outbreaks of viral aetiology were investigated by EIA for the presence of C. difficile toxins. Positive samples were further tested by a cell neutralisation cytotoxicity test, a second EIA and culture. Cultured isolates were tested for the presence of toxin genes, the production of toxins and characterised by 16S rRNA polymerase chain reaction (PCR) and sequencing. Twenty-four samples (3.2%) tested positive in the EIA. Of these 24 positive samples, only two were positive by cytotoxicity and three by a second EIA. Bacterial culture of 21 available stool samples yielded a toxinogenic C. difficile PCR ribotype 001 in one patient sample only. In conclusion, we found no evidence in this retrospective study for an association between viral gastroenteritis outbreaks and C. difficile. The high rate of false-positive EIA samples emphasises the need for second confirmation tests to diagnose CDI.