Evaluation of the Cepheid Xpert Xpress SARS-CoV-2 test for bronchoalveolar lavage

Accurate and rapid laboratory tests are essential for the prompt diagnosis of COVID-19, which is important to patients and infection control. The Xpert Xpress SARS-CoV-2 test is a real-time RT-PCR intended for the qualitative detection of nucleic acid from SARS-CoV-2 in upper respiratory specimens. In this study, we assessed the analytical and clinical performance characteristics of this rapid test for SARS-CoV-2 in 60 bronchoalveolar lavage (BAL) specimens. BAL is a specimen type that is not authorized under EUA for the Xpert Xpress SARS-CoV-2 test. The limit of detection of the Xpert Xpress SARS-CoV-2 test was 500 copies/ml. The overall agreement of the Xpert Xpress SARS-CoV-2 test was 100%. The Xpert Xpress SARS-CoV-2 test is sensitive and specific to aid in diagnosis of COVID-19 using bronchoalveolar lavage.

New Unknown Sars-Cov-2 Virus Variants and Hidden Pandemics Within Them in Developing Countries

It is not known whether one or a combination of different mutations will alter the viral clinical and epidemiological manifestations, transmissibility, virulence, or efficacy of the vaccine. Transmission of the new variant by asymptomatic carriers is also unknown. Vaccines or antiviral agents have not yet induced the pressure of the mutation; however, other mutations are anticipated after global vaccination and after the introduction of proven therapies. Thus, a willingness to rapidly emerge new options is prudent. Less virulent but highly heritable variants can also be expected, which may contribute to herd immunity. There is a need to develop clinical and rapid laboratory tests to monitor vaccinated individuals for secondary infection potentially caused by the new variant. Importantly, restrictive countermeasures, spatial distancing, personal hygiene, travel bans, and facial disguises remain relevant in the fight against the virus.

A Spider Toxin Exemplifies the Promises and Pitfalls of Cell-Free Protein Production for Venom Biodiscovery

Arthropod venoms offer a promising resource for the discovery of novel bioactive peptides and proteins, but the limited size of most species translates into minuscule venom yields. Bioactivity studies based on traditional fractionation are therefore challenging, so alternative strategies are needed. Cell-free synthesis based on synthetic gene fragments is one of the most promising emerging technologies, theoretically allowing the rapid, laboratory-scale production of specific venom components, but this approach has yet to be applied in venom biodiscovery. Here, we tested the ability of three commercially available cell-free protein expression systems to produce venom components from small arthropods, using U2-sicaritoxin-Sdo1a from the six-eyed sand spider Hexophtalma dolichocephala as a case study. We found that only one of the systems was able to produce an active product in low amounts, as demonstrated by SDS-PAGE, mass spectrometry, and bioactivity screening on murine neuroblasts. We discuss our findings in relation to the promises and limitations of cell-free synthesis for venom biodiscovery programs in smaller invertebrates.

Salivary Biomarkers in COVID-19 Patients: Towards a Wide-Scale Test for Monitoring Disease Activity

The ongoing outbreak of coronavirus disease 2019 (COVID-19), which impairs the functionality of several organs, represents a major threat to human health. One of the hardest challenges in the fight against COVID-19 is the development of wide-scale, effective, and rapid laboratory tests to control disease severity, progression, and possible sudden worsening. Monitoring patients in real-time is highly demanded in this pandemic era when physicians need reliable and quantitative tools to prioritize patients’ access to intensive care departments. In this regard, salivary biomarkers are extremely promising, as they allow for the fast and non-invasive collection of specimens and can be repeated multiple times. Methods: We compare salivary levels of immunoglobulin A subclasses (IgA1 and IgA2) and free light chains (kFLC and λFLC) in a cohort of 29 SARS-CoV-2 patients and 21 healthy subjects. Results: We found that each biomarker differs significantly between the two groups, with p-values ranging from 10−8 to 10−4. A Receiving Operator Curve analysis shows that λFLC level is the best-suited candidate to discriminate the two groups (AUC = 0.96), with an accuracy of 0.94 (0.87–1.00 95% CI), a precision of 0.91 (0.81–1.00 95% CI), a sensitivity of 1.00 (0.96–1.00 95% CI), and a specificity of 0.86 (0.70–1.00 95% CI). Conclusion: These results suggest λFLC as an ideal indicator of patient conditions. This hypothesis is strengthened by the consideration that the λFLC half-life (approximately 6 h) is significantly shorter than the IgA one (21 days), thus confirming the potential of λFLC for effectively monitoring patients’ fluctuation in real-time.

Salivary Biomarkers in COVID-19 Patients: The Rabbit out of the Hat!

Background: The ongoing outbreak of Coronavirus Disease 2019 (COVID-19) represents a major threat to human health, which impairs the functionality of several organs. One of the hardest challenges in the fight against COVID-19 is the development of wide-scale, effective, and rapid laboratory tests to control disease severity, progression, and possible sudden worsening. Monitoring patients in real-time is indeed highly demanded in this pandemic era when physicians need reliable and quantitative tools to prioritize patients’ access to intensive care departments. In this regard, salivary biomarkers are extremely promising, as they allow for a fast and non-invasive specimens’ collection, which can be repeated multiple times. Methods: We compare salivary levels of immunoglobulin A subclasses (IgA1 and IgA2) and free-light chains (FLC k and λ) in a cohort of 29 SARS-CoV-2 patients and 21 healthy subjects. Results: We found that each biomarkers differs significantly between the two groups, with p-values ranging from 10-8 to 10-4. The performance ranking of these markers, shows that λFLC level (p=1.4e-8) is the best-suited candidate to discriminate the two groups, with an accuracy of 0.94 (0.87-1.00 95% CI), a precision of 0.91 (0.81-1.00 95% CI), a sensitivity of 1.00 (0.96-1.00 95% CI) and a specificity of 0.86 (0.70-1.00 95% CI). Conclusion: These results suggest λFLC as an ideal indicator of patient conditions. This is more strengthened in consideration that λFLC half-life (approximately 6 hours) is significantly shorter than the IgA one (21 days): thus λFLC appears displaying the potential to effectively monitor patients fluctuation in real-time.

Identification of serodiscordant couples, their clinical and laboratory characteristics, and vulnerabilities of HIV transmission risk in Northeastern Brazil in the era of pre-exposure prophylaxis (PrEP)

Objectives: To evaluate the frequency of HIV serodiscordants couples and their seronegative partners who were candidates for pre-exposure prophylaxis (PrPE), and the knowledge about behavioural measures to reduce virus transmission. Methods: The research was performed in Northeastern Brazil, from February 2016 to March 2017. Ninety HIV-positive individuals (Index) and their HIV-serodiscordant partners (n = 17) were submitted for epidemiological, clinical, and laboratory questionnaires, and for rapid laboratory tests for syphilis, hepatitis B and C. Results: High frequencies of HIV-syphilis (34.4%) and HIV-HBV (3.3%) coinfection were detected in the HIV-positive individuals. Three new HIV cases were detected in partners. Most participants in both groups (85.6%, Index; 94.1%, Partners) had an excellent degree of knowledge regarding HIV transmission, although nine seronegative HIV partners with a high risk of HIV infection were identified (53%). HIV-positive individuals had a high frequency of HIV-syphilis co-infection and 10% of them did not use antiretroviral by personal option. Conclusions: Adoption of PrEP and other preventive measures to prevent HIV transmission in serodiscordants couples should be studied and evaluated.