SARS-CoV-2 Rapid Antigen Test Based on a New Anti-Nucleocapsid Protein Monoclonal Antibody: Development and Real-Time Validation.

SARS-CoV-2 diagnostic tests have become an important tool for pandemic control. Among the alternatives for COVID-19 diagnosis, antigen rapid diagnostic tests (Ag-RDT) are very convenient and widely used. However, as SARS-CoV-2 variants may continuously emerge, the replacement of tests and reagents may be required to maintain the sensitivity of Ag-RDTs.

Capture ELISA for KPC Detection in Gram-Negative Bacilli: Development and Standardisation.

The detection of KPC-type carbapenemases is necessary for guiding appropriate antibiotic therapy and the implementation of antimicrobial stewardship and infection control measures. Currently, few tests are capable of differentiating carbapenemase types, restricting the lab reports to their presence or not. The aim of this work was to raise antibodies and develop an ELISA test to detect KPC-2 and its D179 mutants.

Identification of Zika Virus NS1-Derived Peptides with Potential Applications in Serological Tests.

Zika virus (ZIKV), a mosquito-borne pathogen, is an emerging arbovirus associated with sporadic symptomatic cases of great medical concern, particularly among pregnant women and newborns affected with neurological disorders. Serological diagnosis of ZIKV infection is still an unmet challenge due to the co-circulation of the dengue virus, which shares extensive sequence conservation of structural proteins leading to the generation of cross-reactive antibodies. In this study, we aimed to obtain tools for the development of improved serological tests for the detection of ZIKV infection.

O55 Polysaccharides Are Good Antigen Targets for the Formulation of Vaccines against O55 STEC and Capsulated aEPEC Strains.

The serogroup O55 of is composed of strains whose mechanisms of virulence are different from each other. Since the O55 polysaccharides are present in all O55 strains, and so are the polymers that compose the capsule of O55 atypical enteropathogenic (aEPEC), it was investigated whether anti-O55 antibodies were able to help the innate immune system to eliminate capsulated aEPEC and Shiga toxin-producing (STEC) belonging to the serogroup O55. The results demonstrate that the capsule of EPEC was able to inhibit the deposition of C3b on the bacterial surface and, as a consequence, their lysis by the alternative pathway of the complement system.

Therapeutic Antibodies Against Shiga Toxins: Trends and Perspectives.

Shiga toxins (Stx) are AB-type toxins, composed of five B subunits which bind to Gb host cell receptors and an active A subunit, whose action on the ribosome leads to protein synthesis suppression. The two Stx types (Stx1 and Stx2) and their subtypes can be produced by Shiga toxin-producing strains and some spp. These bacteria colonize the colon and induce diarrhea that may progress to hemorrhagic colitis and in the most severe cases, to hemolytic uremic syndrome, which could lead to death.

Strains Responsible for Cystitis in Female Pediatric Patients with Normal and Abnormal Urinary Tracts Have Different Virulence Profiles.

The role of uropathogenic (UPEC) in colonization and infection of female patients with anatomical and functional abnormalities of the urinary system is elusive. In this study, the phenotype, genotype and the phylogeny of UPEC strains isolated from the urine of pediatric female patients with cystitis of normal and abnormal urinary tract were determined. Multiplex PCR results demonstrated that 86% of the strains isolated from female patients with normal urinary tract (NUT), belonged to the phylo-groups B2 and D.

Anti-DENV-NS1 monoclonal antibody for the differential histopathological diagnosis of hemorrhagic fever caused by dengue.

Dengue is the most prevalent arboviral disease in humans in tropical and subtropical regions, especially in urban areas, and can cause major epidemics. Although a self-limiting illness, it may sometimes have serious hemorrhagic manifestations, and the outcome of dengue hemorrhagic fever has similar clinical manifestations as in other infections, which could result in death. Therefore, autopsy procedures are required under certain circumstances such as in hemorrhagic fevers, sometimes to confirm or to clarify the diagnosis that may have epidemiological consequences.

In Silico Prediction and Design of Uropathogenic Alpha-Hemolysin Generate a Soluble and Hemolytic Recombinant Toxin.

The secretion of α-hemolysin by uropathogenic (UPEC) is commonly associated with the severity of urinary tract infections, which makes it a predictor of poor prognosis among patients. Accordingly, this toxin has become a target for diagnostic tests and therapeutic interventions. However, there are several obstacles associated with the process of α-hemolysin purification, therefore limiting its utilization in scientific investigations.

Heat-Labile Toxin from Enterotoxigenic Causes Systemic Impairment in Zebrafish Model.

Heat-labile toxin I (LT-I), produced by strains of enterotoxigenic (ETEC), causes profuse watery diarrhea in humans. Different in vitro and in vivo models have already elucidated the mechanism of action of this toxin; however, their use does not always allow for more specific studies on how the LT-I toxin acts in systemic tracts and intestinal cell lines. In the present work, zebrafish () and human intestinal cells (Caco-2) were used as models to study the toxin LT-I.

Human microbiota modulation via QseC sensor kinase mediated in the Escherichia coli O104:H4 outbreak strain infection in microbiome model.

Background: The intestinal microbiota plays a crucial role in human health, adjusting its composition and the microbial metabolites protects the gut against invading microorganisms. Enteroaggregative E. coli (EAEC) is an important diarrheagenic pathogen, which may cause acute or persistent diarrhea (≥14 days).

HSP90 Can Be Found in the Cell Surface and Is a Target for Antibodies with Therapeutic Potential.

Paracoccidioidomycosis (PCM) is one of the most frequent systemic mycoses in Latin America. It affects mainly male rural workers in impoverished regions, and the therapy can last up to two years or use drugs that are very toxic. Given the need for novel safe and effective approaches to treat PCM, we have been developing monoclonal antibodies (mAbs) that could be used not only to block specific fungal targets, but also modulate the host's antifungal immunity.

Zebrafish embryo sensitivity test as in vivo platform to anti-Shiga toxin compound screening.

Shiga toxin-producing Escherichia coli (STEC) pathotype secretes two types of AB cytotoxins (Stx1 and Stx2), responsible for complications such as hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS) in infected patients, which could lead to sequels and death. Currently, there is no effective treatment against the cytotoxic effect of these toxins. However, in order to approve any therapy molecule, an animal experiment is required in order to evaluate the efficacy and safety of therapeutic approaches.

Novel Hybrid of Typical Enteropathogenic and Shiga-Toxin-Producing (tEPEC/STEC) Emerging From Pet Birds.

Exotic psittacine birds have been implicated as reservoir of diarrheagenic (), including enteropathogenic (EPEC) and Shiga-toxin producing (STEC). Here, we present a genotypic and phenotypic characterization of typical EPEC/STEC hybrid strains isolated from exotic psittacine birds. The strains were positive for , A, and s2f genes, belong to serotype O137:H6 and ST2678.

Human Recombinant Fab Fragment Neutralizes Shiga Toxin Type 2 Cytotoxic Effects and .

Shiga toxin (Stx) producing (STEC) is responsible for causing hemolytic uremic syndrome (HUS), a life-threatening thrombotic microangiopathy characterized by thrombocytopenia, hemolytic anemia, and acute renal failure after bacterially induced hemorrhagic diarrhea. Until now, there has been neither an effective treatment nor method of prevention for the deleterious effects caused by Stx intoxication. Antibodies are well recognized as affinity components of therapeutic drugs; thus, a previously obtained recombinant human FabC11:Stx2 fragment was used to neutralize Stx2 in vitro in a Vero cell viability assay.

Immunogenic Domains and Secondary Structure of Recombinant Secreted Protein -Secreted Protein B.

Several pathogenic bacteria are able to induce the attaching and effacing (A/E) lesion. The A/E lesion is caused by effector proteins, such as -secreted protein B (EspB), responsible together with -secreted protein D for forming a pore structure on the host cell, which allows the translocation of effector proteins. Different variants of this protein can be found in strains, and during natural infection or when this protein is injected, this leads to variant-specific production of antibodies, which may not be able to recognize other variants of this bacterial protein.

Humoral immune response to Shiga Toxin 2 (Stx2) among Brazilian urban children with hemolytic uremic syndrome and healthy controls.

Background: Shiga toxin (Stx)-producing Escherichia coli (STEC) infection is associated with hemolytic uremic syndrome (HUS), the main cause of acute renal failure in early childhood. Stx is essential in the pathogenesis of HUS, which has been mostly related to Stx2-producing isolates. Very limited data exist on the immune response to STEC in the Brazilian population.

A rapid assay of the sialidase activity in species of the Bacteroides fragilis group by using peanut lectin hemagglutination.

In this study, a novel, simple and rapid hemagglutination assay by using a peanut lectin to detect a neuraminidase activity in strains of the Bacteroides fragilis group was developed. One hundred and fourteen species of the B. fragilis group isolated from children with and without diarrhea and 15 reference strains were evaluated.

Slot blot immunoassay as a tool for plasmid-encoded toxin detection in enteroaggregative Escherichia coli culture supernatants.

Plasmid-encoded toxin (Pet) is a heat-labile enterotoxin encoded in the enteroaggregative Escherichia coli (EAEC) virulence plasmid. Several evidence support the role of this 108-kDa secreted protein in the pathogenesis of EAEC diarrhea. In this study, we standardized a slot blot immunoassay for Pet detection.

Molecular engineering of an EGFP/disintegrin-based integrin marker.

Disintegrins are viper venom peptides, which bind integrins with high affinity (10(-8) M) and selectivity. Among them, eristostatin (Er) selectively binds and inhibits alphaIIbbeta3 integrin function. In this work we have engineered an enhanced green fluorescence protein (EGFP)-tagged Er as an alphaIIbbeta3 biomarker to be used in bioassays involving fluorescence detectors.