Virulence properties of Escherichia coli isolated from ostriches with respiratory disease Terezinha Kno Èbl a,b , Maria R. Baccaro b , Andrea M. Moreno b , Ta Ãnia A.T. Gomes c ,Mo Ãnica A.M. Vieira c , Claudete S.A. Ferreira b , Antonio J. Piantino Ferreira b,* a Departamento de Patologia, Faculdade de Medicina Veterina Âria, Universidade de Guarulhos, Prac Ëa Tereza Cristina, 01 07023-070 Guarulhos, SP, Brazil b Departamento de Patologia, Faculdade de Medicina Veterina Âria e Zootecnia, Universidade de Sa Äo Paulo, Avenue Prof. Dr. Orlando Marques de Paiva, 87 05508-900 Sa Äo Paulo, SP, Brazil c Departamento de Microbiologia e Imunologia, Escola Paulista de Medicina, Universidade Federal de Sa Äo Paulo, R. Botucatu, 862 04023-062 Sa Äo Paulo, SP, Brazil Received 7 November 2000; received in revised form 7 June 2001; accepted 7 June 2001 Abstract Eight Escherichia coli isolates from ostriches with respiratory disease were investigated for the presence of genes encoding the following adhesins: type 1 pili ®m), pili associated with pyelonephritis pap),S®mbriaesfa), a®mbrial adhesin afaI), temperature regulated adhesin, curli crl, csgA)andtemperature-sensitivehemagglutinintsh).GenesforheatlabileLT)andheatstable STa and STb)enterotoxins,Shigatoxinsstx1and stx2),cytotoxicnecrotizingfactor1cnf),alpha- haemolysin hly) and aerobactin aer) production were also investigated. Other characteristics investigated were the presence of hemagglutination activity, growth on an iron-de®cient medium, aerobactin production, serum resistance, adherence to chicken tracheal cells, pathogenicity for day- oldchicks,andserogroup.SerogroupingshowedthatfourisolatesbelongedtoserogroupO2,twoto serogroup O78, one to serogroup O9, and one to serogroup O21. The virulence genes found were: ®m in all eight isolates, csgA in seven, aer in six, and pap, crl and tsh in one isolate each. All isolates analyzed were positive for mannose-resistant hemagglutination, adhered in vitro to ciliated tracheal epithelium, grew on iron-de®cient medium, and showed serum resistance. Pathogenicity tests on day-old chickens revealed one highly pathogenic isolate, three of low pathogenicity and four isolates with intermediate pathogenicity. # 2001 Elsevier Science B.V. All rights reserved. Keywords: Ostrich; Respiratory disease; Escherichia coli; Virulence factors Veterinary Microbiology 83 2001) 71±80 * Corresponding author. Tel.: 55-11-3818-7706; fax: 55-11-3818-7829. E-mail address: ajpferr@usp.br A.J.P. Ferreira). 0378-1135/01/$ ± see front matter # 2001 Elsevier Science B.V. All rights reserved. PII:S0378-113501)00403-5