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The characterization of surface microbiota living in biofilms within livestock buildings has been relatively unexplored, despite its potential impact on animal health. To enhance our understanding of these microbial communities, we characterized 11 spore-forming strains isolated from two commercial broiler chicken farms. Sequencing of the strains revealed them to belong to three species Bacillus velezensis, Bacillus subtilis, and Bacillus licheniformis. Genomic analysis revealed the presence of antimicrobial resistance genes and genes associated with antimicrobial secretion specific to each species. We conducted a comprehensive characterization of the biofilm formed by these strains under various conditions, and we revealed significant structural heterogeneity across the different strains. A macro-colony interaction model was employed to assess the compatibility of these strains to coexist in mixed biofilms. We identified highly competitive B. velezensis strains, which cannot coexist with other Bacillus spp. Using confocal laser scanning microscopy along with a specific dye for extracellular DNA, we uncovered the importance of extracellular DNA for the formation of B. licheniformis biofilms. Altogether, the results highlight the heterogeneity in both genome and biofilm structure among Bacillus spp. isolated from biofilms present within livestock buildings. [ABSTRACT FROM AUTHOR]

Little information about biofilm microbial communities on the surface of livestock buildings is available yet. While these spatially organized communities proliferate in close contact with animals and can harbor undesirable microorganisms, no standardized methods have been described to sample them non-destructively. We propose a reproducible coupon-based capture method associated with a set of complementary ex-situ analysis tools to describe the major features of those communities. To demonstrate the biofilm dynamics in a pig farm building, we analyzed the coupons on polymeric and metallic materials, as representative of these environments, over 4 weeks. Confocal laser scanning microscopy (CLSM) revealed a rapid coverage of the coupons with a thick layer of biological material and the existence of dispersed clusters of active metabolic microorganisms. After detaching the cells from the coupons, counts to quantify the CFU/cm2 were done with high reproducibility. High-throughput sequencing of the 16S rRNA V3-V4 region shows bacterial diversity profiles in accordance with reported bacteria diversity in pig intestinal ecosystems and reveals differences between materials. The coupon-based methodology allows us to deepen our knowledge on biofilm structure and composition on the surface of a pig farm and opens the door for application in different types of livestock buildings. [ABSTRACT FROM AUTHOR]

The genomes of four clinical Gram-negative ESKAPE bacterial strains highly resistant to the last-resort antibiotic colistin were sequenced and analyzed. The strains were found to carry multidrug-resistant genes besides colistin-resistant genes., Competing Interests: The authors declare no conflict of interest.