Virulence characteristics of Escherichia coli isolates obtained from broiler breeders with salpingitis Maria A.R. Monroy a , Terezinha Kno ¨bl b , Jose ´ A. Bottino b , Claudete S. Astolfi Ferreira b , Antonio J. Piantino Ferreira b, * a Facultad de Medicina Veterinaria, Universidad la Salle, Bogota ´, Cundinamarca, Colombia b Departamento de Patologia, Faculdade de Medicina Veterina ´ria e Zootecnia, Universidade de Sa ˜o Paulo, Av. Prof. Dr Orlando Marques de Paiva, 87, 05508-900 Sa ˜o Paulo, SP, Brazil Accepted 17 November 2003 Abstract Thirty isolates of Escherichia coli from broiler breeders with salpingitis were studied. Using the slide agglutination test, the isolates were found to belong to serogroups O1, O2, O5, O36, O45, O53 and O78. Pathogenicity for day-old chicks was determined by air sac inoculation and isolates were categorized as having high, intermediate or low virulence. Growth on iron starvation medium was observed together with aerobactin production. Based on the results of in vitro adherence tests, attachment to oviduct epithelium from old birds was found to be superior to that observed using corresponding material from young birds. DNA hybridization testing for type 1, P, and S fimbriae revealed predominant expression of type 1, correlating with mannose-sensitive hemagglutination using guinea-pig erythrocytes. In this study, P and S fimbriae were not considered to be important adherence factors. Study findings would suggest that, as far as salpingitis is concerned, type 1 fimbriae can play an important role in E. coli infection in breeders. An interesting result to emerge from the study was the observation that E. coli isolates were completely resistant to serum from young breeders, whereas they were completely sensitive using serum from older breeders. Based on serogroups involved, pathogenicity for day-old chicks and virulence indicators, the salpingitis isolates were similar to those from cases of chronic respiratory disease. q 2004 Elsevier Ltd. All rights reserved. Keywords: Escherichia coli; Virulence characteristics; Salpingitis; Chicken Re ´sume ´ Caracte ´ristiques de la virulence de Escherichia coli isole ´es de reproductrices atteintes de salpingite. Trente e ´chantillons d’Escherichia coli isole ´s de reproductrices atteintes de salpingites ont 0147-9571/$ - see front matter q 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.cimid.2004.03.001 Comparative Immunology, Microbiology & Infectious Diseases 28 (2005) 1–15 www.elsevier.com/locate/cimid * Corresponding author. Tel.: þ 55-11-3818-7706; fax: þ55-11-3818-7829. E-mail address: ajpferr@usp.br (A.J.P. Ferreira).