Genomic Characterization of Aeromonas veronii Provides Insights into Taxonomic Assignment and Reveals Widespread Virulence and Resistance Genes throughout the World.

Aeromonas veronii is a Gram-negative bacterial species that causes disease in fish and is nowadays increasingly recurrent in enteric infections of humans. This study was performed to characterize newly sequenced isolates by comparing them with complete genomes deposited at the NCBI (National Center for Biotechnology Information). Nine isolates from fish, environments, and humans from the São Francisco Valley (Petrolina, Pernambuco, Brazil) were sequenced and compared with complete genomes available in public databases to gain insight into taxonomic assignment and to better understand virulence and resistance profiles of this species within the One Health context. One local genome and four NCBI genomes were misidentified as A. veronii. A total of 239 virulence genes were identified in the local genomes, with most encoding adhesion, motility, and secretion systems. In total, 60 genes involved with resistance to 22 classes of antibiotics were identified in the genomes, including mcr-7 and cphA. The results suggest that the use of methods such as ANI is essential to avoid misclassification of the genomes. The virulence content of A. veronii from local isolates is similar to those complete genomes deposited at the NCBI. Genes encoding colistin resistance are widespread in the species, requiring greater attention for surveillance systems.

Downregulation of growth plate genes involved with the onset of femoral head separation in young broilers.

Femoral head separation (FHS) is characterized by the detachment of growth plate (GP) and articular cartilage, occurring in tibia and femur. However, the molecular mechanisms involved with this condition are not completely understood. Therefore, genes and biological processes (BP) involved with FHS were identified in 21-day-old broilers through RNA sequencing of the femoral GP. 13,487 genes were expressed in the chicken femoral head transcriptome of normal and FHS-affected broilers. From those, 34 were differentially expressed (DE; FDR ≤0.05) between groups, where all of them were downregulated in FHS-affected broilers. The main BP were enriched in receptor signaling pathways, ossification, bone mineralization and formation, skeletal morphogenesis, and vascularization. RNA-Seq datasets comparison of normal and FHS-affected broilers with 21, 35 and 42 days of age has shown three shared DE genes (FBN2, C1QTNF8, and XYLT1) in GP among ages. Twelve genes were exclusively DE at 21 days, where 10 have already been characterized (SHISA3, FNDC1, ANGPTL7, LEPR, ENSGALG00000049529, OXTR, ENSGALG00000045154, COL16A1, RASD2, BOC, GDF10, and THSD7B). Twelve SNPs were associated with FHS (p < 0.0001). Out of those, 5 were novel and 7 were existing variants located in 7 genes (RARS, TFPI2, TTI1, MAP4K3, LINK54, and AREL1). We have shown that genes related to chondrogenesis and bone differentiation were downregulated in the GP of FHS-affected young broilers. Therefore, these findings evince that candidate genes pointed out in our study are probably related to the onset of FHS in broilers.

Comprehensive Analyses of Bone and Cartilage Transcriptomes Evince Ion Transport, Inflammation and Cartilage Development-Related Genes Involved in Chickens' Femoral Head Separation.

Femoral head separation (FHS) is usually a subclinical condition characterized by the detachment of articular cartilage from the bone. In this study, a comprehensive analysis identifying shared and exclusive expression profiles, biological processes (BP) and variants related to FHS in the femoral articular cartilage and growth plate in chickens was performed through RNA sequencing analysis. Thirty-six differentially expressed (DE) genes were shared between femoral articular cartilage (AC) and growth plate (GP) tissues. Out of those, 23 genes were enriched in BP related to ion transport, translation factors and immune response. Seventy genes were DE exclusively in the AC and 288 in the GP. Among the BP of AC, the response against bacteria can be highlighted, and for the GP tissue, the processes related to chondrocyte differentiation and cartilage development stand out. When the chicken DE genes were compared to other datasets, eight genes (SLC4A1, RHAG, ANK1, MKNK2, SPTB, ADA, C7 and EPB420) were shared between chickens and humans. Furthermore, 89 variants, including missense in the SPATS2L, PRKAB1 and TRIM25 genes, were identified between groups. Therefore, those genes should be more explored to validate them as candidates to FHS/FHN in chickens and humans.

Molecular screening for the mutation associated with canine degenerative myelopathy (SOD1:c.118G > A) in German Shepherd dogs in Brazil.

Canine Degenerative Myelopathy is a late onset recessive autosomal disease characterized by a progressive ascending degeneration of the spinal cord. Two causal mutations are associated with this disease: a transition (c.118G>A) in exon 2 of the SOD1 that was described in several breeds and a transversion (c.52A>T) in exon 1 of the same gene described in Bernese Mountain dogs. The aim of this study was to understand the impact of the SOD1:c.118G > A mutation by genotyping a population of German Shepherd dogs in Brazil. A PCR-RFLP approach was used to genotype 97 healthy individuals belonging from the Northeast (Bahia and Pernambuco states) and South (Santa Catarina state) regions of Brazil. A total of 95 individuals were successfully genotyped resulting in an observed genotype frequency (with 95% confidence interval) of: 0.758 (0.672-0.844), 0.242 (0.156-0.328) and 0.000 (0.000-0.000) for "GG", "AG" and "AA" genotypes, respectively. To our knowledge, this is the first attempt to describe the presence of the "A" allele associated with CDM (SOD1:c.118G > A) in German Shepherd dogs in Brazil and, as such, these results contribute toward important epidemiological data in this country and to the knowledge of the distribution of the aforementioned mutation worldwide.

The presence of plasmids in Aeromonas hydrophila and its relationship with antimicrobial and heavy metal-resistance profiles / Presença de plasmídeos em Aeromonas hydrophila e sua relação com perfis de resistência aos antimicrobianos e metais pesados

ABSTRACT: Aeromonas hydrophila is a common fish pathogen that causes extensive damage to aquaculture. To develop and implement a more adequate strategy to farm fish, it is crucial to understand the bacterial-resistance levels and their transference dynamics. The objective of this study was to analyze the resistance profile of isolated Aeromonas hydrophila to antimicrobial agents and heavy metals and draw a correlation of the observed profiles with the presence of plasmids. Resistance of the isolated bacteria to antimicrobial agents (oxacilin, gentamicin, tetracycline, and nalidixic acid) and heavy metals (cadmium, lead, copper, and manganese) was verified using the minimum bactericidal concentration (MBC) and minimum inhibitory concentration (MIC) standards. The Multiple Antibiotic Resistance Index (MAR Index) was calculated. Plasmids were extracted by using a common methodology described elsewhere. Mann-Whitney Test, implemented in the R environment, was used to determine the correlation between resistance and plasmids presence. A high resistance to almost all antimicrobial agents and heavy metals was observed, except to gentamicin and cadmium. The MAR index results showed resistance to all antimicrobial profiles. Of the isolated bacteria, 14 showed the presence of plasmids. However, no correlation was noted between the resistance profile and the plasmid presence for these isolates, indicating that the genes responsible for resistance to microbial agents and heavy metals are present in the cromossomic DNA, which in turn suggested the possibility of gene transfer between the isolated bacteria. The resistance to heavy metals can be linked to heavy utilization of fertilizers along the Sao Francisco River.

RESUMO: Bactérias da espécie Aeromonas hydrophila são patógenos que atacam peixes, causando grandes prejuízos à piscicultura. Entender os perfis de resistência dessa bactéria e a capacidade da mesma em transferir tal resistência é importante para implantação de um manejo adequado na produção de peixes. Os objetivos desse estudo foram analisar a resistência de isolados de Aeromonas hydrophila à antimicrobianos e metais pesados e, correlacionar os perfis encontrados com a presença de plasmídeos. A resistência dos isolados aos antimicrobianos (oxacilina, gentamicina, tetraciclina e ácido nalidíxico) e metais pesados (cádmio, chumbo, cobre e manganês) foi verificada pelas técnicas da Concentração Bactericida Mínima (CBM) e Concentração Inibitória Mínima (CIM). Foi calculado o Índice de Resistência Múltipla aos Antimicrobianos (IRMA). Os plasmídeos foram extraídos por metodologias descritas pela literatura. A relação entre a resistência aos antimicrobianos e metais pesados com a presença de plasmídeos foi determinada pelo teste de Mann-Whitney utilizando o ambiente R. Foi observada alta resistência aos antimicrobianos e metais pesados testados, com exceção à gentamicina e cádmio. No IRMA os isolados apresentaram resistência a todos os perfis de antimicrobianos possíveis. Quatorze isolados apresentaram plasmídeos, mas não foi encontrada relação dos perfis de resistência com a presença destes, o que indica que os genes de resistência a esses compostos estejam presentes no DNA cromossômico. Porém apontam a possibilidade de transferência dos genes de resistência entre os isolados. Estes resultados apontam alta resistência dos isolados e capacidade de transmissão dessa resistência a outras bactérias. A resistência aos metais pesados, pode estar ligada ao uso de fertilizantes nas plantações localizadas próximas as margens do Rio São Francisco.