Staphylococcus aureus is a globally significant pathogen associated with severe infections, foodborne illnesses, and animal diseases. Its control has become increasingly challenging due to the spread of antibiotic-resistant strains, highlighting the urgent need for effective alternatives. In this context, bacteriophages have emerged as promising biocontrol agents. This study aimed to characterize the newly isolated Staphylococcus phage CapO46 and evaluate its efficacy in reducing S. aureus in milk. Identified as a new species within the Rosenblumvirus genus, CapO46 exhibited a podovirus-like structure and a small linear dsDNA genome (17,107 bp), with no lysogeny-related, antimicrobial resistance, or virulence genes. Host range assays demonstrated its ability to infect all 31 S. aureus isolates from two different countries and in diverse environmental contexts, achieving high efficiency of plating (EOP > 0.5) in 64.5% of cases. Kinetic analyses revealed rapid adsorption and a short latent period, with a burst size of approximately 30 PFU/cell. In UHT whole-fat milk, CapO46 achieved a maximum reduction of 7.2 log10 CFU/mL in bacterial load after 12 h, maintaining significant suppression (1.6 log10 CFU/mL) after 48 h. Due to its genetic safety, high infectivity across multiple isolates, and antimicrobial activity in milk, CapO46 can be considered a promising candidate for S. aureus biocontrol applications.

The threatened orchid Cattleya milleri is a microendemic orchid of a Brazilian savanna hotspot. As endophytes and mycorrhizae may improve its propagation and conservation, we investigated its root fungal community. Cattleya milleri roots were sampled in five natural sites and at a greenhouse. Fungal root endophytes were isolated for characterization and molecular ITS (Internal Transcribed Spacer) identification. Total DNA was extracted from endorhiza and rhizosphere for ITS amplification and sequencing. Sixteen fungal isolates were clustered in 6 Operational Taxonomic Units (OTUs) and endorhizal and rhizospheric sequences were clustered in 327 OTUs. Endorhiza presented from 25 to 89 OTUs, and rhizosphere 56 OTUs. Cluster analysis showed high divergence between natural and greenhouse fungal communities, but similarity among natural samples. From the 94 genera, 24 were annotated as endophytes, two mycorrhizas, 33 pathotrophs, 40 saprotrophs, and 17 symbiotrophs based on the FunGuild database. Endophytes of the orders Capnodiales, Hypocreales, Pleosporales, and mycorrhizae of Sebacinales occurred in all sites. The mycorrhizae Tulasnella occurred in all natural samples. The interaction with only two mycorrhizal taxa may limit C. milleri distribution. However, the recruitment of many non-mycorrhizal endophytes is essential to natural development. Pleosporales, Tulasnella, and Sebacinalles may be considered for C. milleri propagation and conservation.

Anais do XXXII Congresso Brasileiro de Virologia: Virologia em Casa (978-65-5941-393-5) - Proposal Of A Phage Cocktail For Sulfate-Reducing Bacteria Biofilms Control In Environments Related To The Oil And Gas Industry