Identification of avian pathogenic E. coli O (somatic) antigens

Infections caused by avian pathogenic Escherichia coli (APEC) seriously threaten poultry production and economic losses. These bacteria have several mechanisms that enable them to colonize various ecosystems. Colibacillosis, especially coli-septicemia form, is the most common bacterial disease in the poultry industry all over the world, with critical economic losses, as well as has public health significance. Tube agglutination test (TAT) is one of the ways for epidemiologic investigation of avian colibacillosis, however, due to the initial dilution rate of 10^-1 of antibody, it gives insufficient information. In this paper micro-agglutination test (MAT) method is compared with the TAT method. For this reason, bacteria of E. coli, O2 serogroup, were injected into 14 broiler chickens for 14-day-old. Blood samples were taken 1, 2, and 3 weeks post the injection. Each serum sample was examined with the TAT and MAT methods. The results indicated that the MAT method is more straightforward than the TAT method and can detect lower levels of antibodies to the O (Somatic) antigen of E. coli. The results also indicated that if in the MAT method, the mixtures of antigen and diluted antibodies were incubated at 4 °C, the titration would have been a good correlation with the TAT method.