title: Virulence gene content in Escherichia coli isolates from poultry flocks with clinical signs of colibacillosis in Brazil.
abstract: Escherichia coli is a commensal bacterium of the bird's intestinal tract, but it can invade different tissues resulting in systemic symptoms (colibacillosis). This disease occurs only when the E. coli infecting strain presents virulence factors (encoded by specific genes) that enable the adhesion and proliferation in the host organism. Thus, it is important to differentiate pathogenic (APEC, avian pathogenic E. coli) and non-pathogenic or fecal (AFEC, avian fecal E. coli) isolates. Previous studies analyzed the occurrence of virulence factors in E. coli strains isolated from birds with colibacillosis, demonstrating a high frequency of the bacterial genes cvaC, iroN, iss, iutA, sitA, tsh, fyuA, irp-2, ompT and hlyF in pathogenic strains. The aim of the present study was to evaluate the occurrence and frequency of these virulence genes in E. coli isolated from poultry flocks in Brazil. A total of 138 isolates of E. coli was obtained from samples of different tissues and/or organs (spleen, liver, kidney, trachea, lungs, skin, ovary, oviduct, intestine, cloaca) and environmental swabs collected from chicken and turkey flocks suspected to have colibacillosis in farms from the main Brazilian producing regions. Total DNA was extracted and the 10 virulence genes were detected by traditional and/or real-time PCR. At least 11 samples of each gene were sequenced and compared to reference strains. All 10 virulence factors were detected in Brazilian E. coli isolates, with frequencies ranging from 39.9% (irp-2) to 68.8% (hlyF and sitA). Moreover, a high nucleotide similarity (over 99%) was observed between gene sequences of Brazilian isolates and reference strains. Seventy-nine isolates were defined as pathogenic (APEC) and 59 as fecal (AFEC) based on previously described criteria. In conclusion, the main virulence genes of the reference E. coli strains are also present in isolates associated with colibacillosis in Brazil. The analysis of this set of virulence factors can be used to differentiate between APEC and AFEC isolates in Brazil.
authors.affiliation: Laboratório de Diagnóstico Molecular, Universidade Luterana do Brasil (ULBRA), Av. Farroupilha, 8001, Prédio 22, Sala 312, Bairro São José, CEP 92425-900, Canoas, RS, Brazil.
authors.forename: Silvia
authors.initials: S
authors.lastname: De Carli
authors.affiliation: Laboratório de Diagnóstico Molecular, Universidade Luterana do Brasil (ULBRA), Av. Farroupilha, 8001, Prédio 22, Sala 312, Bairro São José, CEP 92425-900, Canoas, RS, Brazil Simbios Biotecnologia, Rua Cai, 541, Vila Princesa Izabel, CEP 94940-030, Cachoeirinha, RS, Brazil.
authors.forename: Nilo
authors.initials: N
authors.lastname: Ikuta
authors.affiliation: Laboratório de Diagnóstico Molecular, Universidade Luterana do Brasil (ULBRA), Av. Farroupilha, 8001, Prédio 22, Sala 312, Bairro São José, CEP 92425-900, Canoas, RS, Brazil.
authors.forename: Fernanda Kieling Moreira
authors.initials: FK
authors.lastname: Lehmann
authors.affiliation: Laboratório de Diagnóstico Molecular, Universidade Luterana do Brasil (ULBRA), Av. Farroupilha, 8001, Prédio 22, Sala 312, Bairro São José, CEP 92425-900, Canoas, RS, Brazil.
authors.forename: Vinicius Proença
authors.initials: VP
authors.lastname: da Silveira
authors.affiliation: Laboratório de Diagnóstico Molecular, Universidade Luterana do Brasil (ULBRA), Av. Farroupilha, 8001, Prédio 22, Sala 312, Bairro São José, CEP 92425-900, Canoas, RS, Brazil.
authors.forename: Gabriela
authors.initials: G
authors.lastname: de Melo Predebon
authors.affiliation: Simbios Biotecnologia, Rua Cai, 541, Vila Princesa Izabel, CEP 94940-030, Cachoeirinha, RS, Brazil.
authors.forename: André Salvador Kazantzi
authors.initials: AS
authors.lastname: Fonseca
authors.affiliation: Laboratório de Diagnóstico Molecular, Universidade Luterana do Brasil (ULBRA), Av. Farroupilha, 8001, Prédio 22, Sala 312, Bairro São José, CEP 92425-900, Canoas, RS, Brazil Simbios Biotecnologia, Rua Cai, 541, Vila Princesa Izabel, CEP 94940-030, Cachoeirinha, RS, Brazil vagner.lunge@gmail.com.
authors.forename: Vagner Ricardo
authors.initials: VR
authors.lastname: Lunge
mesh_terms: D000818:Animals; D001938:Brazil / Q000453:epidemiology; D002645:Chickens; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism; D005243:Feces / Q000382:microbiology; D008969:Molecular Sequence Data; D011201:Poultry Diseases / Q000453:epidemiology* / Q000382:microbiology; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D017422:Sequence Analysis, DNA / Q000662:veterinary; D037521:Virulence Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D029968:Escherichia coli Proteins; D037521:Virulence Factors
keywords: avian Escherichia coli; colibacillosis; virulence genes