Escherichia coli isolates from 24 sick psittacine birds were serogrouped and investigated for the presence of genes encoding the following virulence factors: attaching and effacing (eae), enteropathogenic E. coli EAF plasmid (EAF), pili associated with pyelonephritis (pap), S fimbriae (sfa), afimbrial adhesin (afa), capsule K1 (neu), curli (crl, csgA), temperature--sensitive hemagglutinin (tsh), enteroaggregative heat-stable enterotoxin-1 (astA), heat--stable enterotoxin -1 heat labile (LT) and heat stable (STa and STb) enterotoxins, Shiga-like toxins (stx1 and stx2), cytotoxic necrotizing factor 1 (cnf1), haemolysin (hly), aerobactin production (iuc) and serum resistance (iss). The results showed that the isolates belonged to 12 serogroups: O7; O15; O21; O23; O54; O64; O76; O84; O88; O128; O152 and O166. The virulence genes found were: crl in all isolates, pap in 10 isolates, iss in seven isolates, csgA in five isolates, iuc and tsh in three isolates and eae in two isolates. The combination of virulence genes revealed 11 different genotypic patterns. All strains were negative for genes encoding for EAF, EAEC, K1, sfa, afa, hly, cnf, LT, STa, STb, stx1 and stx2. Our findings showed that some E. coli isolated from psittacine birds present the same virulence factors as avian pathogenic E. coli (APEC), uropathogenic E. coli (UPEC) and Enteropathogenic E. coli (EPEC) pathotypes.3110916921Baldini, M.M., Kaper, J.B., Levine, M.M., Candy, D.C.A., Moon, H.W., Plasmid-mediated adhesion of enteropathogenic Escherichia coli (1983) J. Pediatr. Gastroenterol. Nutr., 2, pp. 534-538Bangert, R.L., Cho, B.R., Widders, P.R., Strauber, E.H., Ward, A.C.S., A survey of aerobic bacteria and fungi in the healthy psittacine birds (1988) Avian Dis, 32, pp. 46-52Baudry, B., Savarino, S.J., Vial, P., Kaper, J.P., Levine, M.M.A., A sensitive and specific DNMA probe to identify enteroaggregative E. coli, a recently discovered diarrheal pathogen (1990) J. Infect. Dis., 161, pp. 1249-1251Blanco, J.E., Blanco, M., Mora, A., Blanco, J., Production of toxins (enterotoxins, verotoxins, and necrotoxins) and colicins by Escherichia coli strains isolated from septicemic and healthy chickens: Relationship with in vivo pathogenicity (1997) J. Clin. Microbiol., 35, pp. 2953-2957Blanco, M., Blanco, J.E., Gonzalez, E.A., Mora, A., Jansen, W., Gomes, T.A.T., Zerbini, F., Blanco, G., Genes coding for enterotoxins and verotoxins in porcine Escherichia coli strains belonging to different O:K:H serotypes: relationship with toxic phenotypes (1997) J. Clin. Microbiol., 35, pp. 2958-2963Blanco, J.E., Blanco, M., Mora, A., Jansen, W.H., Garcia, V., Vazquez, M.L., Blanco, J., Serotypes of Escherichia coli isolated from septicaemic chickens in Galicia (Northwest Spain) (1998) Vet. Microbiol., 61, pp. 229-235Boom, R., Sol, C.J.A., Salimans, M.M.M., Jansen, C.L., Wertheim-Van Dillen, P.M.E., Van Der Noordaa, J., Rapid and Simple Method for purification of Nucleic Acids (1990) J. Clin. Microbiol., 28, pp. 495-503Delicato, E.R., Brito, B.G., Gaziri, L.C.J., Vidotto, M.C., Virulence associated genes in Escherichia coli isolates from poultry with colibacilosis (2003) Vet. Microbiol., 94, pp. 97-103Dorrestein, G.M., Buitelaar, M.N., Van der Hage, M.H., Zwart, P., Evaluation of a bacteriological and mycological examination of psittacine birds (1985) Avian Dis, 29, pp. 951-962Dozois, M.C., Dho-Moulin, M., Brée, A., Fairbrother, J.M., Desaultels, C., Curtiss III, R., Relationship between the Ths autotransporter and pathogenicity of avian Escherichia coli and localization and analysis of the tsh genetic region (2000) Infect. Immun., 68, pp. 4145-4154Dziva, F., Stevens, M.P., Colibacilosis in poultry: unravelling the molecular basis of virulence of avian pathogenic Escherichia coli in their natural hosts (2008) Avian Pathol, 37, pp. 355-366Ewers, C., Janben, T., Kiebling, S., Philipp, H.C., Wieler, L., Molecular epidemiology of avian pathogenic Escherichia coli (APEC) isolated from colisepticemia in poultry (2004) Vet. Microbiol., 104, pp. 91-101Flammer, K., Drewes, L.A., Species-related differences in the incidence of Gram-negative bacteria isolated from the cloaca of clinically normal psittacine birds (1988) Avian Dis, 32, pp. 79-83Graham, C.L., Graham, D.L., Occurrence of Escherichia coli in feces of psittacine birds (1978) Avian Dis, 22, pp. 717-720Guinée, P.A., Jansen, W.H., Wadström, T., Sellwood, R., Escherichia coli associated with neonatal diarrhea in piglets and calves (1981) Curr. Top. Vet. Anim. Sci., 13, pp. 126-162Hoefer, H.L., Diseases of the gastrointestinal tract (1997) Avian Medicine and Surgery, pp. 419-453. , Altman R.B., Clubb S.L., Dorestein G.M. & Quesenbery K. (Eds), Saunders Company, PhiladelphiaHorne, S.M., Pfaff-Mcdonough, S.J., Giddings, C.W., Nolan, L.K., Cloning and sequencing of the iss gene from a virulent avian Escherichia coli (2000) Avian Dis, 44, pp. 179-184Janben, T., Schwarz, C., Preikschat, P., Voss, M., Philipp, H.C., Wieler, L.H., Virulence-associated genes in avian pathogenic Escherichia coli (APEC) isolated from internal organs of poultry having died from colibacillosis (2001) Int. J. Med. Microbiol. ., 291, pp. 371-378Jerse, A.E., Jun, Y., Tall, B.D., Kaper, J.B., A genetic locus of enteropathogenic Escherichia coli necessary for the production of attaching and effacing lesions on tissue culture cells (1990) Proc. Natl Acad. Sci. USA, 87, pp. 7839-7843Johnson, J.T., Kariyawasam, S., Wannemuehler, Y., Mangiamele, P., Johnson, S.J., Doetkott, C., Skyberg, J.A., Nolan, L., The genome sequence of avian pathogenic Escherichia coli strain O1:K1:H7 shares strong similarities with human extraintestinal pathogenic E. coli genomes (2007) J. Bacteriol., 189, pp. 3228-3226Knöbl, T., Baccaro, M.R., Moreno, A.M., Vieira, M.A., Ferreira, C.S., Ferreiara, A.J., Virulence properties of Escherichia coli isolated from ostriches with respiratory disease (2001) Vet. Microbiol., 2283, pp. 71-80Knöbl, T., Godoy, S.N., Matushima, E.R., Guimarães, M.B., Ferreiara, A.J., Caracterização molecular dos fatores de virulência de estirpes de Escherichia coli isoladas de papagaios com colibacilose aviária (2008) Braz. J. Vet. Res. Anim. Sci., 45, pp. 54-60Knöbl, T., Menão, M., Escherichia coli enteropatogênica (EPEC) isoladas de psitacídeos (2010) FIEP Bulletin, 80, pp. 839-841Maas, R., An improved colony hybridization method with significantly increased sensitivity for detection of single genes (1983) Plasmid, 10, pp. 296-298Marietto-Gonçalves, G.A., Almeida, S.M., Lima, E.T., Andreatti Filho, R.L., Detecção de Escherichia coli e Salmonella spp. Em microbiota intestinal de Psittaciformes em fase de reabilitação e soltura (2010) Braz. J. Vet. Res. Anim. Sci., 47, pp. 185-189Marietto-Gonçalves, G.A., Lima, E.T., Sequeira, J.L., Andreatti Filho, R.L., Colisepticemia em papagaio verdadeiro (Amazona aestiva) (2007) Revta Braz. Saúde Prod. Anim., 8, pp. 56-60Mattes, B.R., Consiglio, S.A.A., Almeida, B.Z., Guido, M.C., Orsi, R.B., Silva, R.M., Costa, A., Knöbl, T., Influência da biossegurança na colonização intestinal por Escherichia coli em psitacídeos (2005) Arqs Inst. Biológico, 72, pp. 13-16. , São PauloMaurer, J.J., Brown, T.P., Steffens, W.L., Thayer, S.G., The occurrence of ambient temperature-regulated adhesins, curli, and the temperature-sensitive hemagglutinin Tsh among avian Escherichia coli (1998) Avian Dis, 42, pp. 106-118Menão, M.C., Ferreira, C.S.A., Castro, A.G.M., Knöbl, T., Ferreira, A.J.P., Sorogrupos de Escherichia coli isolados de frangos de corte com doença respiratória crônica (2002) Arqs Inst. Biológico, 65, pp. 15-17. , São PauloMonroy, M.A., Knöbl, T., Bottino, J.A., Ferreira, C.S., Ferreira, A.J.P., Virulence characteristics of Escherichia coli isolates obtained from broilers breeders with salpingitis (2005) Comp. Immunol. Microbiol. Infect. Dis., 28, pp. 1-15Nakazato, G., Campos, T.A., Stehling, E.G., Brocchi, M., Da Silveira, W.D., Virulence factors of avian pathogenic Escherichia coli (APEC) (2009) Pesq. Vet. Bras., 29, pp. 479-486Nardi, A.R., Salvatori, M.R., Coswig, L.T., Gatti, M.S., Leite, D.S., Valadares, G.F., Neto, M.G., Yano, T., Type 2 heat-labile enterotoxin (LTII) producing Escherichia coli isolated from ostriches with diarrhea (2005) Vet. Microbiol., 105, pp. 245-249Ngeleka, M., Brereton, L., Brown, G., Fairbrother, J.M., Pathotypes of avian Escherichia coli as related to tsh-, pap-, pil-, and iuc-DNA sequences, and antibiotic sensitivity of isolates from internal tissues and the cloacae of broilers (2002) Avian Dis, 46, pp. 143-152Olsivik, O., Strockbine, N.A., (1993) Diagnostic Molecular Microbiology: Principles and applications, pp. 271-276. , Persing D.H., Smith T.F., Tenover F.C., T.J. White T.J. (Eds), American Society for Microbiology, Washington, DCPakpinyo, S., Ley, D.H., Barnes, J.P., Vaillancourt, J.P., Guy, J.S., Prevalence of enteropathogenic Escherichia coli in naturally occurring cases of poultry enteritis-mortality syndrome (2002) Avian Dis, 46, pp. 360-369Parreira, V.R., Gyles, C.L., A novel pathogenicity island intregrated adjacent to the thrWtRNA gene of avian pathogenic Escherichia coli encodes a vacuolating autotransporter toxin (2003) Infect. Immun., 71, pp. 5087-5096Parreira, V.R., Yano, T., Cytotoxin produced by Escherichia coli isolated from chickens with swollen head syndrome (SHS) (1998) Vet. Microbiol., 62, pp. 111-119Pollard, D.R., Johnson, W.M., Lior, H., Tyler, S.D., Rozes, K.R., Rapid and specific detection of verotoxin genes in Escherichia coli by the polymerase chain reaction (1990) J. Clin. Microbiol., 28, pp. 540-545Pourbakhsh, S.A., Dho-Moulin, M., Brée, A., Desautels, C., Doize, B.M., Fairbrother, J.M., Localization of the in vivo expression of P and F1 fimbriae in chickens experimentally inoculated with pathogenic Escherichia coli (1997) Microbiol. Pathog., 22, pp. 331-341Provence, D.L., Curtiss, R., Role of crl in avian pathogenic Escherichia coli: a knockout mutation of crl does not affect hemagglutination activity, fibronectin binding, or curli production (1992) Infect. Immun., 60, pp. 4460-4467Ron, E.Z., Host specificity of septicemic Escherichia coli: Human and avian pathogens (2006) Curr. Opin. Microbiol., 9, pp. 28-32Saidenberg, A.B.S., (2008) Detecção dos fatores de virulência de Escherichia coli isoladas de psitacídeos com diferentes manifestações clínicas, p. 91. , Dissertação de Mestrado, Faculdade de Medicina Veterinária e Zootecnia, USP, São PauloSalvatori, M.R., Yano, T., Carvalho, H.E., Parreira, V.R., Gyles, C.L., Vacuolating cytotoxin produced by avian pathogenic Escherichia coli (2001) Avian Dis, 45, pp. 43-51Schremmer, C., Lohr, J.E., Wastlhuber, U., Kösters, J., Ravelshofer, K., Steinrück, H., Wieler, L.H., Enteropathogenic Escherichia coli in psittaciformes (1999) Avian Pathol, 28, pp. 349-354Schultsz, C., Pool, G.J., Van Ketel, R., Wevek, D., Speelman, P., Dankert, J., Detection of enterotoxigenic Escherichia coli in stool samples by using nonradioactively labeled oligonucleotide DNA probes and PCR (1994) J. Clin. Microbiol., 32, pp. 2393-2397Stathopoulus, C., Provence, D.L., Curtiss, R., Characterization of the avian pathogenic Escherichia coli hemagglutinin Tsh, a member of the immunoglobulin A protease-type family of autotransporters (1999) Infect. Immun., 67, pp. 772-781Styles, D.K., Flammer, K., Congo red binding of Escherichia coli isolated from the cloacae of psittacine birds (1991) Avian Dis, 35, pp. 46-48Tsuji, T., Joya, J.E., Honda, T., Miwatani, T., A heat-labile enterotoxin (LT) purified from chicken enterotoxigenic Escherichia coli is identical to porcine LT (1990) FEMS Microbiol. Lett., 55, pp. 329-332Tsukamoto, T., PCR method for detection of K1 antigen and serotypes of Escherichia coli isolated from extraintestinal infection (1997) Kansenshogaku Zashi, 71, pp. 125-129Vila, J., Vargas, M., Henderson, I.R., Gascon, J., Nataro, J.P., Enteroaggregative Escherichia coli virulence factors in traveler's diarrhea strains (2000) J. Infect. Dis, 182, pp. 1780-1783Vidal, M., Kruger, E., Dúran, C., Lagos, R., Levine, M., Prado, V., Toro, C., Vidal, R., Single multiple PCR assay to identify simultaneously the si categories of diarrheagenic Escherichia coli associated with enteric infections (2005) J. Clin. Microbiol., 43, pp. 5362-5365Woodward, M.J., Carroll, P.J., Wray, C., Detection of entero and verocyto-toxin genes in Escherichia coli from diarrhea disease in animals using polymerase chain reaction (1992) Vet. Microbiol., 31, pp. 251-261Yamamoto, S., Terai, A., Yuri, K., Kurazono, H., Takeda, Y., Yoshida, O., Detection of urovirulence factors in Escherichia coli by multiplex polymerase chain reaction (1995) FEMS Immunol. Med. Microbiol., 12, pp. 85-9