Tipagem molecular, detecção de genes de virulência e determinação do potencial patogênico de isolados de Escherichia coli de patos (Cairina moschata), perus (Meleagris gallopavo), galinhas (Gallus gallus)

• Autor(a) principal: Almeida, Ana Maria de Souza
• Data de Publicação: 2019
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/10105
• topic: Antimicrobianos; APEC; Heterogeneidade; Patogenicidade; Genes de virulência; Antimicrobials; APEC; Heterogeneity; Pathogenicity; Virulence genes; CIENCIAS AGRARIAS::MEDICINA VETERINARIA

The general objective of this work is to evaluate the phylogenetics and to detect virulence genes from Escherichia coli isolates from different bird species, as well as to investigate their pathogenic potential in fertile broiler eggs. In the present study three experiments were carried out to analyze, in different aspects, E. coli isolates from different bird species. In experiment 1, E. coli isolated from ducks and turkeys were inoculated into broiler chicks one day to evaluate the pathogenicity of the strains. Fifty isolates of E. coli originating from ducks and 50 isolates from turkeys were tested for the genes iss, iucD, papC and tsh, all commonly found in APEC. Of the 100 isolates of E.coli analyzed, 42% (42/100) detected one or more genes and only 14.2% (6/42) had the four genes studied. After PCR, the positive strains were selected for the four genes common to APEC. Three isolates from ducks and three turkeys were purified separately and six inoculants were inoculated at 107 CFU / mL and inoculated via air sac in one - day - old chicks to evaluate the pathogenicity of these six positive isolates for the four genes. The chicks were evaluated twice a day for ten days in relation to mortality rate, clinical signs and macroscopic findings. The challenged chicks presented respiratory signs (sneezing, nasal discharge and rales) and macroscopic lesions such as aerossaculitis, persistence of the yolk sac, pericarditis and exudate in the nasal sinuses. In view of the results, it is concluded that E.coli originating from both ducks and turkeys are potentially pathogenic for day-old challenged cuttlefish chicks. In the experiment 2, embryos of broiler chickens were challenged with E. coli isolates positive for the iss, tsh, papC and iucD genes from hen, broiler, duck and turkey to analyze the pathological and hematological conditions , besides the performance of broiler chickens kept up to 42 days of age. Embryos with 18 days of incubation were challenged, via air chamber, with 0.1 mL of four different inoculants, according to the treatment, (T2 - E.coli of hen chicken, T3 - E.coli of broiler, T4 - E.coli of duck and T5 - E. coli of turkey) with concentration of 107 CFU / mL and with sterile saline solution (T1 - control group). Embryonic and post - hatch mortality rates, clinical signs, hematological alterations, interference of zootechnical performance and macroscopic findings during the incubation period and rearing up to 42 days of life were evaluated. At 14, 28 and 42 days, one bird from each of the four replicates of the five treatments. Regardless of the species of origin, E.coli isolates were not able to cause significant mortality in embryos challenged at 18 days of incubation. At birth and up to 42 days of age, broiler chickens developed respiratory disease, worsened zootechnical performance and there were no significant haematological changes. In the experiment 3, 33 E. coli isolates from ducks, turkeys, chickens and pigeons were evaluated by PFGE and antimicrobial susceptibility test to characterize their respective phylogenetic profiles and susceptibility to antimicrobials commonly used in poultry farming. E. coli originated from ducks, turkeys, chickens and pigeons grouped into a group with 41.1% similarity. Resistance to different antimicrobials tested (ampicillin, amoxicillin, ceftiofur, doxycycline, enrofloxacin, neomycin, sulfametazole, sulfonamide, tetracycline, cotrimoxazole and chloranfericol) was observed among the 33 isolates of E. coli, mainly tetracyclines, followed by fluoroquinolones and sulfonamides. It is concluded that E.coli originating from birds have different profiles and behaviors.