Omori, E. | bioRxiv Science

bioRxiv2022

Incidence, antifungal resistance properties, and virulence traits of candida species isolated from HIV/AIDS Patients from the hospital system in Kenya.

Candidiasis is the most common fungal infection in hospitalized patients with acquired immune deficiency syndrome resulting to morbidity and mortality. This study aimed at characterizing, incidence, susceptibility, resistance genes, antibiofilm activity, and virulence traits of Candida species isolated from HIV-Infected patients. One hundred and eighty-one samples were collected and cultured on Sabouraud Dextrose Agar, biochemical tests and confirmed using automated Vitek-2 (R) Compact bioMerieux followed by susceptibility tests. were done by use of various conventional antifungals against the isolates using standard procedures. Virulence factors, biofilm formations and resistance genes of Candida strains were determined. Out of the 181 samples, 46 were identified as Candida spp., 20 C. albicans (43.5%), 6 C. tropicalis (13.0%), 8 C. krusei (17.4%), 4 C. glabrata (8.7%), 3 C. famata (6.5%), 3 C. parapsilosis (6.5%), and 2 C. guilliermondii (4.3%). All the Candida albicans isolated were both Gram positive and Germ test tube test positive. Eighteen (90%) of the isolates were susceptible to Clotrimazole at a concentration of 5 g/mL - 10g/mL followed by 17 (85%) isolates to Panosoconazole at a concentration of 0.002 g/mL - 5g/mL. Eight (40.0 %) of the Candida albicans isolates possessed the gene (cdr1) that was observed at 286 bp. Virulence enzymes was determined in which 100% produced Haemolysin, followed by proteinase (75.0%), phospholipase (50%), coagulase at (50%) and lastly capsulase (25.0%). Fluconazole and Clotrimazole did not inhibit growth of C. albicans at high concentrations but from our study, it was deduced that they inhibit biofilm formation at lower concentrations. C. albicans isolates were resistant to multiple antifungal including those commonly used in the management on HIV/AIDs patient. This attributed to resistant genes and produced various virulence factors that were found to be present in the isolates. Therefore, there is a need to carry out regular surveillance on antifungal drug resistance.

microbiology↗

bioRxiv2021

Combined computational and cellular screening identifies synergistic inhibition of SARS-CoV-2 by lenvatinib and remdesivir

Rapid repurposing of existing drugs as new therapeutics for COVID-19 has been an important strategy in the management of disease severity during the ongoing SARS-CoV-2 pandemic. Here, we used high-throughput docking to screen 6000 compounds within the DrugBank library for their potential to bind and inhibit the SARS-CoV-2 3CL main protease, a chymotrypsin-like enzyme that is essential for viral replication. For 19 candidate hits, parallel in vitro fluorescence-based protease-inhibition assays and Vero-CCL81 cell-based SARS-CoV-2 replication-inhibition assays were performed. One hit, diclazuril (an investigational anti-protozoal compound), was validated as a SARS-CoV-2 3CL main protease inhibitor in vitro (IC50 value of 29 {micro}M) and modestly inhibited SARS-CoV-2 replication in Vero-CCL81 cells. Another hit, lenvatinib (approved for use in humans as an anti-cancer treatment), could not be validated as a SARS-CoV-2 3CL main protease inhibitor in vitro, but serendipitously exhibited a striking functional synergy with the approved nucleoside analogue remdesivir to inhibit SARS-CoV-2 replication, albeit this was specific to Vero-CCL81 cells. Lenvatinib is a broadly-acting host receptor tyrosine kinase (RTK) inhibitor, but the synergistic effect with remdesivir was not observed with other approved RTK inhibitors (such as pazopanib or sunitinib), suggesting that the mechanism-of-action is independent of host RTKs. Furthermore, time-of-addition studies revealed that lenvatinib/remdesivir synergy probably targets SARS-CoV-2 replication subsequent to host-cell entry. Our work shows that combining computational and cellular screening is a means to identify existing drugs with repurposing potential as antiviral compounds. Future studies could be aimed at understanding and optimizing the lenvatinib/remdesivir synergistic mechanism as a therapeutic option.

microbiology↗