Nível de conhecimento de tutores de cães e gatos sobre zoonosesLevel of knowledge on zoonoses in dog and cat owners Nivel de conocimiento sobre zoonosis en dueños de perros y gatos

No abstract

Tambaqui or cachama ( Colossoma macropomum ) is one of the most important neotropical freshwater fish used for aquaculture in South America, and its production is concentrated at low latitudes (close to the Equator, 0°), where the water temperature is warm. Therefore, understanding how selection shapes genetic variations and structure in farmed populations is of paramount importance in evolutionary biology. High‐throughput sequencing to generate genome‐wide data for fish species allows for elucidating the genomic basis of adaptation to local or farmed conditions and uncovering genes that control the phenotypes of interest. The present study aimed to detect genomic selection signatures and analyze the genetic variability in farmed populations of tambaqui in South America using single‐nucleotide polymorphism (SNP) markers obtained with double‐digest restriction site‐associated DNA sequencing. Initially, 199 samples of tambaqui farmed populations from different locations (located in Brazil, Colombia, and Peru), a wild population (Amazon River, Brazil), and the base population of a breeding program (Aquaculture Center, CAUNESP, Jaboticabal, SP, Brazil) were genotyped. Observed and expected heterozygosity was 0.231–0.350 and 0.288–0.360, respectively. Significant genetic differentiation was observed using global F ST analyses of SNP loci ( F ST = 0.064, p < 0.050). Farmed populations from Colombia and Peru that differentiated from the Brazilian populations formed distinct groups. Several regions, particularly those harboring the genes of significance to aquaculture, were identified to be under positive selection, suggesting local adaptation to stress under different farming conditions and management practices. Studies aimed at improving the knowledge of genomics of tambaqui farmed populations are essential for aquaculture to gain deeper insights into the evolutionary history of these fish and provide resources for the establishment of breeding programs.

Streptococcus agalactiae, group B Streptococcus (GBS), is the main bacterial pathogen of cultured Nile tilapia in many countries and causes extensive deaths in all stages of the farming cycle throughout the year. This study investigated the genetic diversity, virulence, presence of antibiotic resistance genes and antimicrobial susceptibility of 72 GBS linked to mass mortalities of cultured Nile tilapia in Brazil. Isolate identity was confirmed by morphological, biochemical and molecular analyses. Capsular serotype, multi-locus sequence typing (MLST) allelic profiles and putative pathogenic factors were identified by polymerase chain reaction (PCR), gel electrophoresis, sequencing and molecular analyses of different genes. The presence of antimicrobial resistance genes and antimicrobial susceptibility to florfenicol (FFC), oxytetracycline (OTC), thiamphenicol (TAP) and their combination were evaluated by PCR, followed by gel electrophoresis, and broth microdilution antimicrobial susceptibility testing, respectively. All clinical isolates studied were confirmed to be GBS, one from serotype III (IA2022) and 71 from serotype Ib, suggesting that serotype Ib was the most prevalent strain between 2011 and 2016 in the south and southern and southeastern regions of Brazil. Eight different allelic profiles were identified for the first time, being adhP-52, pheS-2, atr-31, glnA-4, sdhA-2, tkt-19 the most predominant. Between one (glcK) and three (adhP and glnA) alleles were present at each locus. All strains, except IA2022, showed a partial gene deletion event on the glcK gene. The surface protein Rib and hypervirulent GBS adhesin BibA were detected in all strains, except for 18P, which was negative for rib. On the other hand, α and β antigens of the C protein were only detected in IA2022. All antimicrobials showed high minimum inhibitory concentration (MIC ≥ 16 ug/mL) values against several strains with negative results for resistance genes. Despite indifference and antagonism being the most predominant activities in all combinations evaluated, the record of synergism, including in a strain with a resistance gene and phenotypic resistance, suggests that combination therapy can have therapeutic efficacy when well planned. The combination involving OTC and TAP or FFC is a likely candidate for improving the treatment of streptococcosis using combination therapy, even for strains showing phenotypic and genotypic resistance to OTC. This study provides pertinent data on pathogenic GBS genetic diversity, virulence, the presence of antibiotic resistance genes and antimicrobial susceptibility, which may be useful in the development of effective vaccines and therapeutic strategies for the prevention and control of streptococcosis in aquaculture farms.