Comparison of capillary blood and plasma samples for the evaluation of seroprevalence to SARS-CoV-2 antibodies by lateral flow immunoassay in a university population in Medellín, Colombia, 2020.

Objectives: The aim of this study was to estimate the seroprevalence of anti-SARS-CoV-2 antibodies using the SARS-CoV-2 antibody test in a university population. Capillary blood and plasma samples were compared and correlated with symptomatology to establish rapid treatment processes and develop a public health strategy within the community. Study design: Descriptive study of seroprevalence of anti-SARS-CoV-2 antibodies in a university population. Methods: Standardised and validated laboratory serological tests were used to assess the immune response detected in capillary blood and plasma samples. In this study, 280 participants from the University Colegio Mayor de Antioquia in the Municipality of Medellín, Colombia, were tested for SARS-CoV-2 antibodies in capillary blood and plasma samples between November 2020 and January 2021. Results: In total, 29 (11.2%) individuals had positive results for anti-SARS-CoV-2 antibodies (IgG/IgM); 28 (96.6%) had positive results in plasma samples and 11 (37.9%) in capillary blood samples. The two tests were compared, and the overall sensitivity and specificity of capillary vs plasma samples was 36.7% and 99.6%, respectively. Conclusions: Anti-SARS-CoV-2 antibodies (IgG/IgM) can be used to estimate the seroprevalence in populations, including immunity by vaccination; however, capillary blood samples should not be used to detect previous infection as they provide low sensitivity compared to plasma samples.

Whole-Genome Sequence of Bioactive Compound-Producing Pseudomonas aeruginosa Strain LV.

Pseudomonas aeruginosa is known for a high adaptive capacity due to the ability to synthesize several compounds that give advantages for competing with other microorganisms in the environment. The LV strain synthesizes bioactive compounds, mainly by secondary metabolism, with antitumor and antimicrobial activities against microbial pathogens.

Corrigendum: Determining the Targets of Fluopsin C Action on Gram-Negative and Gram-Positive Bacteria.

[This corrects the article DOI: 10.3389/fmicb.2020.01076.].

Determining the Targets of Fluopsin C Action on Gram-Negative and Gram-Positive Bacteria.

The antibiotic activity of metalloantibiotic compounds has been evaluated since the 90s, and many different modes of action were characterized. In the last decade, the effects of secondary metabolites produced by Pseudomonas aeruginosa LV strain, including a cupric compound identified as Fluopsin C, were tested against many pathogenic bacteria strains, proving their high antibiotic activity. In the present study, the bactericidal mechanisms of action of Fluopsin C and the semi-purified fraction F4A were elucidated. The results found in electron microscopy [scanning electron microscopy (SEM) and transmission electronic microscopy (TEM)] demonstrated that both Fluopsin C and F4A are affecting the cytoplasmatic membrane of Gram-positive and Gram-negative bacteria. These results were confirmed by fluorescence microscopy, where these bacteria presented permeabilization of their cytoplasmatic membranes after contact with the semi-purified fraction and pure compound. Using electronic and fluorescence microscopy, along with bacterial mutant strains with marked divisional septum, the membrane was defined as the primary target of Fluopsin C in the tested bacteria.

Fluopsin C for Treating Multidrug-Resistant Infections: In vitro Activity Against Clinically Important Strains and in vivo Efficacy Against Carbapenemase-Producing Klebsiella pneumoniae.

The increasing emergence of multidrug-resistant (MDR) organisms in hospital infections is causing a global public health crisis. The development of drugs with effective antibiotic action against such agents is of the highest priority. In the present study, the action of Fluopsin C against MDR clinical isolates was evaluated under in vitro and in vivo conditions. Fluopsin C was produced in cell suspension culture of Pseudomonas aeruginosa LV strain, purified by liquid adsorption chromatography and identified by mass spectrometric analysis. Bioactivity, bacterial resistance development risk against clinically important pathogenic strains and toxicity in mammalian cell were initially determined by in vitro models. In vivo toxicity was evaluated in Tenebrio molitor larvae and mice. The therapeutic efficacy of intravenous Fluopsin C administration was evaluated in a murine model of Klebsiella pneumoniae (KPC) acute sepsis, using six different treatments. The in vitro results indicated MIC and MBC below 2 µg/mL and low bacterial resistance development frequency. Electron microscopy showed that Fluopsin C may have altered the exopolysaccharide matrix and caused disruption of the cell wall of MDR bacteria. Best therapeutic results were achieved in mice treated with a single dose of 2 mg/kg and in mice treated with two doses of 1 mg/kg, 8 h apart. Furthermore, acute and chronic histopathological studies demonstrated absent nephrotoxicity and moderate hepatotoxicity. The results demonstrated the efficacy of Fluopsin C against MDR organisms in in vitro and in vivo models, and hence it can be a novel therapeutic agent for the control of severe MDR infections.