Dengue virus (DENV) is the most important viral pathogen transmitted by Aedes sp. mosquitoes and the causative agent of dengue fever. According to WHO, over 40% of the world population is at risk from dengue and about 2.5% of those affected die each year. Our laboratory has previously identified a novel bacterium in the gut of field caught Aedes mosquitoes that had interesting properties with regards to vector competence. It was identified as Chromobacterium Panama (Csp_P), and studies have shown that it inhibit DENV infection in the mosquito. Further studies showed that the Csp_P culture supernatant could inhibit DENV infection in vitro. Based on these findings, we characterized several biochemical features and the mode of action of the putative anti-DENV factors. The Csp_P-derived anti-DENV factors were heat-stable at 70°C and the activity was enriched in the protein fraction, with molecular weights ranging from 50-100kDa. The activity seems to be associated with a Csp_P secreted multiprotein complex or protein oligomer. We also documented an apparent loss of the DENV envelope protein upon exposure to this protein fraction, which most likely account for abolished viral attachment to host cells. Additionally, proteomic analysis of the fraction identified 33 unique Csp_P proteins, including an extracellular cholesterol oxidase that has been indirectly linked to viral replication in several studies. Several bacterial metalloproteases were also identified, and may be responsible for the proteolytic degradation of the DENV envelope protein. Together, our study characterized an important microbial-derived protein extract with anti-DENV activity in vitro
