Diagnostic potential of blood plasma longitudinal viscosity measured using Brillouin light scattering.

Blood plasma viscosity (PV) is an established biomarker for numerous diseases. Measurement of the shear PV using conventional rheological techniques is, however, time consuming and requires significant plasma volumes. Here, we show that Brillouin light scattering (BLS) and angle-resolved spectroscopy measurements of the longitudinal PV from microliter-sized plasma volumes can serve as a proxy for the shear PV measured using conventional viscometers. This is not trivial given the distinct frequency regime probed and the longitudinal viscosity, a combination of the shear and bulk viscosity, representing a unique material property on account of the latter. We demonstrate this for plasma from healthy persons and patients suffering from different severities of COVID-19 (CoV), which has been associated with an increased shear PV. We further show that the additional information contained in the BLS-measured effective longitudinal PV and its temperature scaling can provide unique insight into the chemical constituents and physical properties of plasma that can be of diagnostic value. In particular, we find that changes in the effective longitudinal viscosity are consistent with an increased suspension concentration in CoV patient samples at elevated temperatures that is correlated with disease severity and progression. This is supported by results from rapid BLS spatial-mapping, angle-resolved BLS measurements, changes in the elastic scattering, and anomalies in the temperature scaling of the shear viscosity. Finally, we introduce a compact BLS probe to rapidly perform measurements in plastic transport tubes. Our results open a broad avenue for PV diagnostics based on the high-frequency effective longitudinal PV and show that BLS can provide a means for its implementation.

The effect of early remdesivir administration in COVID-19 disease progression in hospitalised patients.

BACKGROUND: Antiviral drugs have become crucial in managing COVID-19, reducing complications and mortality. Remdesivir has emerged as an effective therapeutic drug for hospitalized patients at risk of disease progression, especially when alternative treatments are infeasible. While the recommended treatment duration of remdesivir extends up to 7 days post-symptom onset, this study examines how early remdesivir administration impacts clinical outcomes. METHODS: We conducted a retrospective analysis using clinical data from consecutively PCR confirmed SARS-CoV­2 adult patients (≥ 18 years) who received remdesivir during their hospitalization at the department of infectious diseases, Klinik Favoriten in Vienna. The data covered the period from July 1, 2021, to April 31, 2022. Patients were divided into two groups based on the timing of remdesivir administration: an early group (0-3 days since symptom onset) and a late group (≥ 4 days since symptom onset). The primary outcome was in-hospital disease progression, assessed using the WHO COVID-19 Clinical Progression Scale (≥ 1 point increase). Multivariable logistic regression, adjusted for age, sex, SARS-CoV­2 variant, and COVID-19 vaccination status, was used to assess clinical outcomes. RESULTS: In total 219 patients were included of whom 148 (67.6%) were in the early group and 71 (32.4%) were in the late group. The average age was 66.5 (SD: 18.0) years, 68.9% of the patients were vaccinated, and 72.6% had the Omicron virus variant. Late remdesivir administration was associated with a significantly higher probability of needing high-flow oxygen therapy (OR 2.52, 95% CI 1.40-4.52, p = 0.002) and ICU admission (OR 4.34, 95% CI 1.38-13.67, p = 0.012) after adjusting for confounders. In the late group there was a trend towards a higher risk of clinical worsening (OR 2.13, 95% CI 0.98-4.64, p = 0.056) and need for any oxygen therapy (OR 1.85, 95% CI 0.94-3.64, p = 0.074). CONCLUSION: Compared to patients who received remdesivir within the first 3 days after symptom onset, administering remdesivir after day 3 in hospitalized COVID-19 patients is associated with higher risk for complications, such as the need for high-flow oxygen therapy and ICU admission.

Point-of-Care Method T2Bacteria®Panel Enables a More Sensitive and Rapid Diagnosis of Bacterial Blood Stream Infections and a Shorter Time until Targeted Therapy than Blood Culture.

BACKGROUND: Rapid diagnosis and identification of pathogens are pivotal for appropriate therapy of blood stream infections. The T2Bacteria®Panel, a culture-independent assay for the detection of Escherichia coli, Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa in blood, was evaluated under real-world conditions as a point-of-care method including patients admitted to the internal medicine ward due to suspected blood stream infection. METHODS: Patients were assigned to two groups (standard of care-SOC vs. T2). In the SOC group 2 × 2 blood culture samples were collected, in the T2 group the T2Bacteria®Panel was performed additionally for pathogen identification. RESULTS: A total of 94 patients were included. Pathogens were detected in 19 of 50 patients (38%) in the T2 group compared to 16 of 44 patients (36.4%) in the SOC group. The median time until pathogen detection was significantly shorter in the T2 group (4.5 h vs. 60 h, p < 0.001), as well as the time until targeted therapy (antibiotic with the narrowest spectrum and maximal effectiveness) (6.4 h vs. 42.2 h, p = 0.043). CONCLUSIONS: The implementation of the T2Bacteria®Panel for patients with sepsis leads to an earlier targeted antimicrobial therapy resulting in earlier sufficient treatment and decreased excessive usage of broad-spectrum antimicrobials.