First reported genome of an mcr-9-mediated colistin-resistant Salmonella Typhimurium isolate from Brazilian livestock

Objectives: To investigate the genetic context of colistin resistance in anmcr-9-harbouring Salmonella Typhimurium ST19 strain from swine in Brazil. Methods: Minimum inhibitory concentrations (MIC) to colistin were determined by broth microdilution. Whole-genome sequencing was performed on an Illumina MiSeq system, followed by de novo genome assembly using SPAdes 1.13.1. The draft genome sequence was annotated in Prokka using KBase online server. Downstream analyses for resistome and plasmid detection were performed using online tools available at the Center for Genomic Epidemiology. The strain was typed in silico using MLST 2.0. Phylogenetic analysis involving 24 other genomes of Salmonella Typhimurium ST19 and mcr-9-harbouring Salmonella Typhimurium isolated from humans, livestock and foodstuff in different regions was also performed. Results: Assembly of the draft genome resulted in 5245 protein-coding sequences, 14 rRNAs, 83 tRNAs and a GC content of 51.81%. The strain was identified as Salmonella Typhimurium ST19 harbouring a 265.5-kb pN1566-2 plasmid carrying genes encoding resistance to colistin (mcr-9.1), aminoglycosides (aadA1), tetracycline [tet(C)] and sulfonamides (sul1). Our findings indicate that the Salmonella Typhimurium ST19 strain in this study showed low genetic variability compared with Salmonella Typhimurium ST19 isolated from swine and poultry in Brazil, and was less related to those reported in other countries. Conclusions: This is the first reported genome of a phenotypically colistin-resistant Salmonella Typhimurium harbouring the mcr-9 variant in Brazilian livestock. This genome will aid global investigations on epidemiological and evolutionary aspects of plasmid-mediated colistin resistance and the role of colistin-resistant Salmonella Typhimurium ST19 lineage as a zoonotic pathogen

MBSP1: a biosurfactant protein derived from a metagenomic library with activity in oil degradation

Microorganisms represent the most abundant biomass on the planet; however, because of several cultivation technique limitations, most of this genetic patrimony has been inaccessible. Due to the advent of metagenomic methodologies, such limitations have been overcome. Prevailing over these limitations enabled the genetic pool of non-cultivable microorganisms to be exploited for improvements in the development of biotechnological products. By utilising a metagenomic approach, we identifed a new gene related to biosurfactant production and hydrocarbon degradation. Environmental DNA was extracted from soil samples collected on the banks of the Jundiaí River (Natal, Brazil), and a metagenomic library was constructed. Functional screening identifed the clone 3C6, which was positive for the biosurfactant protein and revealed an open reading frame (ORF) with high similarity to sequences encoding a hypothetical protein from species of the family Halobacteriaceae. This protein was purifed and exhibited biosurfactant activity. Due to these properties, this protein was named metagenomic biosurfactant protein 1 (MBSP1). In addition, E. coli RosettaTM (DE3) strain cells transformed with the MBSP1 clone showed an increase in aliphatic hydrocarbon degradation. In this study, we described a single gene encoding a protein with marked tensoactive properties that can be produced in a host cell, such as Escherichia coli, without substrate dependence. Furthermore, MBSP1 has been demonstrated as the frst protein with these characteristics described in the Archaea or Bacteria domains

Ruminant fat intake improves gut microbiota, serum inflammatory parameter and fatty acid profile in tissues of Wistar rats

Research Areas: Science & Technology - Other TopicsThis study tested the hypothesis that naturally and industrially produced trans-fatty acids can exert distinct efects on metabolic parameters and on gut microbiota of rats. Wistar rats were randomized into three groups according to the diet: CONT-control, with 5% soybean oil and normal amount of fat; HVF-20% of hydrogenated vegetable fat (industrial); and RUM-20% of ruminant fat (natural). After 53 days of treatment, serum biochemical markers, fatty acid composition of liver, heart and adipose tissue, histology and hepatic oxidative parameters, as well as gut microbiota composition were evaluated. HVF diet intake reduced triglycerides (≈ 39.39%) and VLDL levels (≈ 39.49%). Transfatty acids levels in all tissue were higher in HVF group. However, RUM diet intake elevated amounts of anti-infammatory cytokine IL-10 (≈ 14.7%) compared to CONT, but not to HVF. Furthermore, RUM intake led to higher concentrations of stearic acid and conjugated linoleic acid in all tissue; this particular diet was associated with a hepatoprotective efect. The microbial gut communities were signifcantly diferent among the groups. Our results show that ruminant fat reversed the hepatic steatosis normally caused by high fat diets, which may be related to the remodelling of the gut microbiota and its anti-infammatory potential.info:eu-repo/semantics/publishedVersio

Microbial culture in minimal medium with oil favors enrichment of biosurfactant producing genes

The waste produced by petrochemical industries has a significant environmental impact. Biotechnological approaches offer promising alternatives for waste treatment in a sustainable and environment-friendly manner. Microbial consortia potentially clean up the wastes through degradation of hydrocarbons using biosurfactants as adjuvants. In this work, microbial consortia were obtained from a production water (PW) sample from a Brazilian oil reservoir using enrichment and selection approaches in the presence of oil as carbon source. A consortium was obtained using Bushnell-Haas (BH) mineral medium with petroleum. In parallel, another consortium was obtained in yeast extract peptone dextrose (YPD)-rich medium and was subsequently compared to the BH mineral medium with petroleum. Metagenomic sequencing of these microbial communities showed that the BH consortium was less diverse and predominantly composed of Brevibacillus genus members, while the YPD consortium was taxonomically more diverse. Functional annotation revealed that the BH consortium was enriched with genes involved in biosurfactant synthesis, while the YPD consortium presented higher abundance of hydrocarbon degradation genes. The comparison of these two consortia against consortia available in public databases confirmed the enrichment of biosurfactant genes in the BH consortium Functional assays showed that the BH consortium exhibits high cellular hydrophobicity and formation of stable emulsions, suggesting that oil uptake by microorganisms might be favored by biosurfactants. In contrast, the YPD consortium was more efficient than the BH consortium in reducing interfacial tension. Despite the genetic differences between the consortia, analysis by a gas chromatography-flame ionization detector showed few significant differences regarding the hydrocarbon degradation rates. Specifically, the YPD consortium presented higher degradation rates of C12 to C14 alkanes, while the BH consortium showed a significant increase in the degradation of some polycyclic aromatic hydrocarbons (PAHs). These data suggest that the enrichment of biosurfactant genes in the BH consortium could promote efficient hydrocarbon degradation, despite its lower taxonomical diversity compared to the consortium enriched in YPD medium. Together, these results showed that cultivation in a minimal medium supplemented with oil was an efficient strategy in selecting biosurfactant-producing microorganisms and highlighted the biotechnological potential of these bacterial consortia in waste treatment and bioremediation of impacted areas