Antimicrobial Resistance of Coagulase-positive Staphylococcus Isolated From Healthy Crioulo Horses and Associated Risk Factors.

Antimicrobial resistance (AMR) is a global concern that must be addressed from a one health perspective. Horses are companion animals and their contact with humans facilitates exchange of resistant bacteria. This study aimed to evaluate AMR of coagulase-positive Staphylococcus (CoPS), including Staphylococcus aureus, isolated from healthy Crioulo horses. Swab samples from nostrils (n = 214) and skin (n = 107) of 107 horses from Porto Alegre, South Brazil, were used for CoPS isolation. The isolates were evaluated for AMR and a multivariate logistic regression was applied to identify the risk factors associated to this outcome, using information on horses' management and installations where they were maintained. A total of 143 CoPS were isolated from 79 horses (73.8%), of which 8 (5.6%) were S. aureus. The isolates showed resistance to seven of 10 tested antimicrobials and 38.5% (55/143) of them were resistant to at least one antimicrobial. One isolate (0.7%; 1/143) was classified as multidrug-resistant. Regarding S. aureus, 62.5 % (5/8) showed AMR, but none were methicillin-resistant. The risk factors associated with CoPS' antimicrobial resistance were lower frequency of bed changing (OR = 6.40; P = .001) and nonaccumulation of bed materials (OR = 3.47; P = .002). The results point that healthy horses have antimicrobial-resistant CoPS and S. aureus in their microbiota, which may be of concern for animal and human health. Moreover, bed management was associated with AMR, which can serve as a guide for best practices to be adopted to avoid the occurrence of resistant bacteria in these animals.

Trypanosoma cruzi Malic Enzyme Is the Target for Sulfonamide Hits from the GSK Chagas Box.

Chagas disease, an infectious condition caused by Trypanosoma cruzi, lacks treatment with drugs with desired efficacy and safety profiles. To address this unmet medical need, a set of trypanocidal compounds were identified through a large multicenter phenotypic-screening initiative and assembled in the GSK Chagas Box. In the present work, we report the screening of the Chagas Box against T. cruzi malic enzymes (MEs) and the identification of three potent inhibitors of its cytosolic isoform (TcMEc). One of these compounds, TCMDC-143108 (1), came out as a nanomolar inhibitor of TcMEc, and 14 new derivatives were synthesized and tested for target inhibition and efficacy against the parasite. Moreover, we determined the crystallographic structures of TcMEc in complex with TCMDC-143108 (1) and six derivatives, revealing the allosteric inhibition site and the determinants of specificity. Our findings connect phenotypic hits from the Chagas Box to a relevant metabolic target in the parasite, providing data to foster new structure-activity guided hit optimization initiatives.

Anti-ganglioside antibodies in patients with Zika virus infection-associated Guillain-Barré Syndrome in Brazil.

Zika virus infection is associated with the development of Guillain-Barré syndrome (GBS), a neurological autoimmune disorder caused by immune recognition of gangliosides and other components at nerve membranes. Using a high-throughput ELISA, we have analyzed the anti-glycolipid antibody profile, including gangliosides, of plasma samples from patients with Zika infections associated or not with GBS in Salvador, Brazil. We have observed that Zika patients that develop GBS present higher levels of anti-ganglioside antibodies when compared to Zika patients without GBS. We also observed that a broad repertoire of gangliosides was targeted by both IgM and IgG anti-self antibodies in these patients. Since Zika virus infects neurons, which contain membrane gangliosides, antigen presentation of these infected cells may trigger the observed autoimmune anti-ganglioside antibodies suggesting direct infection-induced autoantibodies as a cause leading to GBS development. Collectively, our results establish a link between anti-ganglioside antibodies and Zika-associated GBS in patients.

A blockage monoclonal antibody protocol as an alternative strategy to avoid anti-CD38 interference in immunohematological testing.

BACKGROUND: As CD38 is expressed on red blood cells (RBCs), the plasma of patients on daratumumab (DARA) reacts with the panel cells of pretransfusion tests, masking underlying alloantibodies. The treatment of RBCs with dithiothreitol (DTT) is the most disseminated method to overcome DARA effect on immunohematological tests, but it hampers the identification of potentially harmful antibodies. Our goal was to validate a new strategy, the blockage monoclonal antibody protocol (BMAP), to mitigate the DARA interference on RBCs using anti-CD38 and antihuman globulin. METHODS: Samples of patients receiving DARA were included in the study. Sera were tested using both DTT- and BMAP-treated RBCs, which comprised three steps: 1) titration of monoclonal anti-CD38, 2) treatment of RBCs obtained from donors with anti-CD38, and 3) blockage of anti-CD38-adsorbed RBCs with antihuman globulin. RESULTS: Twenty patients were included in the study. Donor RBCs were treated with anti-CD38 and successfully blocked with antihuman globulin. In 19 patients, DARA-mediated agglutination was eliminated using both DTT- and BMAP-treated RBCs. In one patient, agglutination persisted when tested against the BMAP-treated RBCs, and alloantibodies were identified. Patient samples were mixed with commercial anti-D, -C, -e, -K, -Jka, -Kpb and tested against antigen-positive BMAP-treated RBCs, resulting in detection of these antibodies. CONCLUSION: This study validated a new strategy to minimize the interference of DARA on immunohematological tests. The protocol preserves the integrity of RBC antigens, permitting the detection of antibodies from all blood group systems. The BMAP has potential use in other situations where specific antibodies may interfere with pretransfusion screening.

First Nonphosphorylated Inhibitors of Phosphoglucose Isomerase Identified by Chemical Library Screening.

Human African trypanosomiasis, Chagas disease, and leishmaniasis are human infections caused by kinetoplastid parasites of the genera Trypanosoma and Leishmania. Besides their severity and global impact, treatments are still challenging. Currently available drugs have important limitations, highlighting the urgent need to develop new drugs. Phosphoglucose isomerase (PGI) is considered a promising target for the development of antiparasitic drugs, as it acts on two essential metabolic pathways, glycolysis and gluconeogenesis. Herein, we describe the identification of new nonphosphorylated inhibitors of Leishmania mexicana PGI ( LmPGI), with the potential for the development of antiparasitic drugs. A fluorescence-based high-throughput screening (HTS) assay was developed by coupling the activities of recombinant LmPGI with glucose-6-phosphate dehydrogenase and diaphorase. This coupled assay was used to screen 42,720 compounds from ChemBridge and TimTec commercial libraries. After confirmatory assays, selected LmPGI inhibitors were tested against homologous Trypanosoma cruzi and humans. The PGI hits are effective against trypanosomatid PGIs, with IC50 values in the micromolar range, and also against the human homologous enzyme. A computational analysis of cavities present on PGI's crystallographic structure suggests a potential binding site for the proposed mixed-type inhibition mechanism.