Clinical Evaluation of Roche SD Biosensor Rapid Antigen Test for SARS-CoV-2 in Municipal Health Service Testing Site, the Netherlands

Rapid detection of infection is essential for stopping the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The Roche SD Biosensor rapid antigen test for SARS-CoV-2 was evaluated in a nonhospitalized symptomatic population. We rapid-tested a sample onsite and compared results with those from reverse transcription PCR and virus culture. We analyzed date of onset and symptoms using data from a clinical questionnaire. Overall test sensitivity was 84.9% (95% CI 79.1–89.4) and specificity was 99.5% (95% CI 98.7–99.8). Sensitivity increased to 95.8% (95% CI 90.5–98.2) for persons who sought care within 7 days of symptom onset. Test band intensity and time to result correlated strongly with viral load; thus, strong positive results could be read before the recommended time. Approximately 98% of all viable specimens with cycle threshold <30 were detected. Rapid antigen tests can detect symptomatic SARS-CoV-2 infections in the early phase of disease, thereby identifying the most infectious persons.

Shedding of Yellow Fever Virus From an Imported Case in the Netherlands After Travel to Brazil

We report yellow fever infection in a Dutch traveler returning from Brazil. Yellow fever virus (YFV) was identified in serum and urine samples over a period of 1 month. Yellow fever virus genome sequences from the patient clustered with recent Brazilian YFV and showed with limited nucleotide changes during the resolving infection.

Cell-line dependent antiviral activity of sofosbuvir against Zika virus

The recent epidemic of Zika virus (ZIKV) in the Americas and its association with fetal and neurological complications has shown the need to develop a treatment. Repurposing of drugs that are already FDA approved or in clinical development may shorten drug development timelines in case of emerging viral diseases like ZIKV. Initial studies have shown conflicting results when testing sofosbuvir developed for treatment of infections with another Flaviviridae virus, hepatitis C virus. We hypothesized that the conflicting results could be explained by differences in intracellular processing of the compound. We assessed the antiviral activity of sofosbuvir and mericitabine against ZIKV using Vero, A549, and Huh7 cells and measured the level of the active sofosbuvir metabolite by mass spectrometry. Mericitabine did not show activity, while sofosbuvir inhibited ZIKV with an IC₅₀ of ∼4 μM, but only in Huh7 cells. This correlated with differences in intracellular concentration of the active triphosphate metabolite of sofosbuvir, GS-461203 or 007-TP, which was 11-342 times higher in Huh7 cells compared to Vero and A549 cells. These results show that a careful selection of cell system for repurposing trials of prodrugs is needed for evaluation of antiviral activity. Furthermore, the intracellular levels of 007-TP in tissues and cell types that support ZIKV replication in vivo should be determined to further investigate the potential of sofosbuvir as anti-ZIKV compound.

Diagnostic performance of influenza viruses and RSV rapid antigen detection tests in children in tertiary care

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The here studied rapid antigen detection test (RADT) BinaxNOW RSV has a high sensitivity and positive predictive value.

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RADT BinaxNOW Influenza A&B has a relatively low sensitivity and positive predictive value.

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We advise a restricted use of RADT BinaxNOW Influenza A&B in a tertiary paediatric care setting.

Background

Rapid antigen detection tests (RADTs) are increasingly used to detect influenza viruses and respiratory syncytial virus (RSV). However, their sensitivity and specificity are a matter of debate, challenging their clinical usefulness.

Objectives

Comparing diagnostic performances of BinaxNow Influenza AB^® (BNI) and BinaxNow RSV^® (BNR), to those of real-time reverse transcriptase PCR (RT-PCR), virus isolation and direct immunofluorescence (D-IF) in paediatric patients.

Study design

Between November 2005 and September 2013, 521 nasal washings from symptomatic children (age <5 years) attending our tertiary care centre were tested, with a combination of the respective assays using RT-PCR as gold standard.

Results

Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of BNI were 69% (confidence interval [CI] [51–83]), 96% [94–97], 55% [39–70] and 98% [96–99] respectively. Of eleven false-negative samples, RT-PCR Ct-values were higher than all RT-PCR positive test results (27 vs 22, p = 0.012). Of twenty false-positive samples, none were culture positive and two tested positive in D-IF.

Sensitivity, specificity, PPV and NPV for BNR were 79% [73–85], 98% [96–99], 97% [93–99] and 88% [84–91]. Of the 42 false-negative samples the median Ct-value was higher than that of all RT-PCR positive samples (31 vs 23, p < 0.0001). Five false-positive samples were detected. Three of these tested positive for RSV in virus isolation and D-IF.

Conclusions

RADTs have a high specificity with BNR being superior to BNI. However, their relative low sensitivity limits their usefulness for clinical decision making in a tertiary care paediatric hospital.

Severe asymptomatic coronary obstruction in chronic hemodialysed patient - a case report

Introduction. Arterial stiffness and vascular calcifications are independent predictors of cardiovascular morbidity and mortality in the chronic kidney disease (CKD) stage 5D population. According to the guidelines, patients on renal replacement therapy represent a very high cardiovascular risk class. Case report. We report the case of a 67-year-old hypertensive male patient, known with CKD stage 5D on hemodialysis (three times per week), secondary bone mineral disease, admitted for progressive right leg pain. The physical examination detected right dorsalis pedis artery pulse absence. Blood biochemistry emphasized hypercalcemia, hyperphosphatemia, increased alkaline phosphatase, metabolic acidosis, hypoalbuminemia, iPTH values above upper limits. The X-ray of right shin highlighted a vascular calcification with a "train track" aspect on the tibial-peroneal artery trunk and the thoracic X-ray (performed with low ray regime) showed calcium deposits in coronary arteries walls. Legs arteriography and coronary angiography were performed revealing multiple lesions on investigated vessels with an 80% narrowing of right coronary artery. The particularity of the case lies in the absence of angina in a chronic hemodialysis patient in whom multiple significant angiographically stenosis of the coronary arteries were found and successful endovascular therapy was performed. Conclusion. The broadening of the indication for coronary angiography should be considered in certain asymptomatic CKD stage 5D patients based on a risk score involving calcium, phosphate, PTH and acid-base imbalances, while considering their major influence on the structure and tone of vascular walls thus on cardiovascular morbidity and mortality rates. Abbreviations. ABI = ankle-brachial index,CAD = coronary artery disease,CKD = chronic kidney disease,CT = computed tomography, EBCT = electron-beam computed tomography,ESRD = end-stage renal disease,GFR = glomerular filtration rate,iPTH = intact parathormon,PCI = percutaneous coronary intervention.

The role of oral sodium bicarbonate supplementation in maintaining acid-base balance and its influence on the cardiovascular system in chronic hemodialysis patients - results of a prospective study

Background: Major acid-base variations during dialysis and the imbalances in serum calcium levels intensified by them play a role in cardiovascular damage of hemodialysis patients. Early vascular walls modifications can be objectified by determining the pulse wave velocity (PWV) - a marker of vascular stiffness that is associated with increased risk of cardiovascular events. Material and methods: This was a prospective study conducted on 63 chronic hemodialysis patients with diuresis above 500 mL/ 24 hours and predialysis blood pressure below 160 mmHg (treatment controlled) randomized in two groups for 12 months - the study group receiving interdialitic oral sodium bicarbonate doses and control group, without oral sodium bicarbonate supplementation, but receiving higher bicarbonate prescriptions in dialysis. All the patients were monthly evaluated by biochemical tests (serum calcium, phosphate, iPTH, bicarbonate), the assessment of prescribed doses of phosphate binders being undergone. Two PWV determinations and chest X-ray exams for coronary calcifications were done - at the beginning and end of the study for every patient. Results: In the study group (n = 29), the mean age was 56.48 ± 12.78 years and the average duration of dialysis was 55.51 ± 34.53 months, the mean dialysis bicarbonate was 29.81 ± 1.41 mEq/ L and 27 of them (subgroup 0) had alkaline reserve (AR) 20-22 mEq/ L. The control group (n = 34) had a mean age of 57.35 ± 15.32 years and the mean dialysis duration 59.67 ± 34.79 months, with an average level of dialysis bicarbonate of 33 ± 2.2 mEq/ L necessary to maintain AR within guidelines. Depending on the mean AR obtained, this group was divided into three subgroups (subgroup 1, subgroup 2, and subgroup 3). There were statistically significant differences regarding the necessary of dialysis bicarbonate (p < 0.001), average serum calcium levels (p < 0.001) and serum phosphorus (p < 0.001), as well as PWV mean values and the number of vascular calcifications (p = 0.036) between the study and the control group. The average dose of phosphate binders was significantly higher in the study group (p = 0.01). At the end of the study, the serum iPTH average levels were decreased in the study group (p < 0.001) and significantly increased in the control group (p < 0.001). Conclusions: Avoiding large variations in serum bicarbonate levels is an important step in hemodialysis patients' management because wide acidosis-alkalosis variation can increase cardiovascular risks in terms of altering the vessel walls elasticity and favoring their calcifications. Abbreviations: GFR = glomerular filtration rate,PWV = pulse wave velocity, iPTH = intact parathyroid hormone,AR = alkaline reserve, BP = blood pressure,mEq = milliequivalents,L = liter.

Emerging Viruses in the Republic of Suriname: Retrospective and Prospective Study into Chikungunya Circulation and Suspicion of Human Hantavirus Infections, 2008-2012 and 2014

INTRODUCTION

Suriname is a country on the northeastern Atlantic coast of South America. It is unique in the sense that different ethnic cultures live together within the country, resulting in high levels of transport of both humans and products between the Asian, African, and European continents as well as the Caribbean. Travel is only one of the many factors present in Suriname contributing to the risk for the emergence or introduction of any infectious disease. Recently, circulation of both chikungunya virus (CHIKV) and hantavirus was reported in areas neighboring Suriname. Here we report a retrospective and prospective study into chikungunya and hantavirus circulation.

METHODS

A chikungunya and hantavirus retrospective serological study was conducted on samples submitted for dengue, leptospirosis, and/or influenza virus diagnostics between 2008 and 2012 to the Bureau of Public Health in Suriname. This was followed by a prospective CHIKV serological and molecular surveillance study until the detection of the first autochthonous CHIKV cases in Suriname in May and June of 2014.

RESULTS

None of the tested samples showed the presence of CHIKV antibodies in the retrospective serological study. Prospective testing of CHIKV-suspected patients resulted in the detection of the first autochthonous CHIKV cases in Suriname in May, 2015. In one sample, we were able to isolate and sequence the virus. Retrospective testing for the presence of hantavirus antibodies showed a relative high response in both pan-hantavirus enzyme-linked immunosorbent assay (ELISA) and immunofluorescence assay (IFA). However, neutralization tests did not yield any evidence for infection with either Seoul or Andes hantavirus.

CONCLUSION

Here we report the presence of CHIKV in the republic of Suriname and the first serological indication of hantavirus infections in symptomatic patients.

Persistent spiking fever in a child with acute myeloid leukemia and disseminated infection with enterovirus

We here report a 7 year old acute myeloid leukemia patient with persistent spiking fever likely caused by chronic echovirus 20 infection. After immunoglobulin substitution fevers subsided and the virus was cleared. Enterovirus infection should be considered in immunocompromised patients with unexplained persistent fever.

Validation of a multiplex reverse transcriptase PCR ELISA for the detection of 19 respiratory tract pathogens

INTRODUCTION

Since acute respiratory tract infections inflict a high burden of disease in children worldwide, a multiplex reverse transcription polymerase chain reaction combined with a microwell hybridization assay (m-RT-PCR-ELISA) to detect 19 different respiratory pathogens was developed and validated.

METHODS

A total of 430 respiratory specimens were retrospectively tested in parallel by both the advanced 19-valent m-RT-PCR-ELISA as well as by culture or individual RT-PCR assays used in clinical routine.

RESULTS

The mean (median) sensitivity of the m-RT-PCR-ELISA in the retrospective test was 93.3% (95.1%; range 83.3-100 %), and the mean (median) specificity was 99.8 and 100 % (range 98.6-100 %), respectively. The mean positive predictive value was 99.3 % (range 93.4-100 %) and the mean negative predictive value was 95.3 % (range 98.4-100 %). Feasibility and clinical value of the 19-valent method was prospectively shown on 16,231 incoming clinical specimens from patients between 0 and 16 years of age with acute respiratory tract infections admitted to pediatric hospitals or private practices from October 2003 to June 2010 in three regions in Germany (Kiel, Mainz, Freiburg; Freiburg to June 2007 only). At least one microorganism was detected in 10,765 of 16,231 (66.3 %) clinical specimens: 5,044 RV, 1,999 RSV, 1,286 AV, 944 EV, 737 seasonal IVA, 173 pandemic IVA H1N1-2009, 899 MPV, 518 CV, 383 PIV3, 268 PIV1, 259 Mpn, 205 IVB, 164 PIV2, 144 PIV4, 103 Bp, 29 Cpn and 29 Bpp, while reovirus and Lpn were not present in these specimens from a pediatric population. More than one organism could be detected in 13.4 % of the specimens.

CONCLUSIONS

The m-RT-PCR-ELISA evaluated here improves the spectrum for diagnosing respiratory infections and is a feasible instrument for individual diagnostic and epidemiological studies.

Evaluation of a multiplex reverse transcriptase PCR ELISA for the detection of nine respiratory tract pathogens

BACKGROUND

A multiplex reverse transcription (RT) polymerase chain reaction combined with a microwell hybridization assay (m-RT-PCR-ELISA) was previously developed to detect nine different microorganisms: enterovirus (EV), influenza virus type A (IVA) and type B (IVB), respiratory syncytial virus (RSV), parainfluenzavirus type 1 (PIV1) and type 3 (PIV3), adenovirus (AV), Mycoplasma pneumoniae (Mpn), Chlamydia pneumoniae (Cpn) in a single test. These organisms do not usually colonize the respiratory tract of humans, but, if present, it may be assumed they are involved in respiratory disease.

OBJECTIVES AND STUDY DESIGN

The m-RT-PCR-ELISA was tested on (i) culture supernatants of unknown contents, (ii) by determining the analytical sensitivity of 10-fold serial dilutions of culture supernatants and (iii) by determining clinical sensitivity in a retrospective study on 411 clinical specimens. The specimens were re-tested in parallel by m-RT-PCR-ELISA versus the gold standard culture and immunfluorescence, and versus individual RT-PCR.

RESULTS

(i) The 9-valent m-RT-PCR-ELISA shows 83% to 100% concordant results on 103 culture supernatants containing different organisms. (ii) The analytical sensitivity was as follows: higher sensitivity of the 9-valent m-RT-PCR-ELISA in comparison to culture in the cases of PIV3, IVA and IVB (factor 10) and AV and EV (factor 100), and lower sensitivity in case of RSV and PIV1 (factor 10). (iii) The agreement with the gold standard in the kappa statistic was excellent for RSV (kappa = 0.937), IVA (kappa = 0.940), very good for PIV1 (kappa = 0.914), IVB (kappa = 0.907) and satisfactory for PIV3 (kappa = 0.410). For AV, EV and Mpn the m-RT-PCR-ELISA preliminary could be qualified as very good, based on the data derived on culture supernatants. Information about the validity for Cpn is limited.

CONCLUSION

The m-RT-PCR-ELISA is a feasible, sensitive and specific method for detection of a broad spectrum of organisms. It is suitable for individual as well as epidemiological diagnosis.