EXPERIMENTAL REPRODUCTION OF ESCHERICHIA-COLI CELLULITIS AND SEPTICEMIA IN BROILER-CHICKENS

Experimental reproduction of avian cellulitis was conducted by subcuta neous inoculation of 25-day-oId broiler chickens with a field isolate of serogroup O78 Escherichia coli. Development of tile cellulitis lesi on occurred as early as 24 h post-infection Reproduction of cellulitis occurred in 98% of inoculated birds, and E. coli was isolated from > 75% of cellulitis lesions. In addition to cellulitis, other lesions, i ncluding pericarditis, airsacculitis, osteomyelitis, arthritis, and pe rihepatitis, occurred in > 80% of birds inoculated with E. colt. Bacte remia occurred as early as 6 h post-infection and dramatically decline d by 5 days post-infection. Seventeen of 53 (29%) birds inoculated wit h E. coli developed a fatal infection between 1 and 6 days postinfecti on, and bacteria were isolated from lesions in 98% birds. In contrast, E, coli was not isolated h om lesions in birds that survived until da ys 7-14 post-infection, Birds that survived with cellulitis and other lesions until day 14 post-infection had a significantly lower body wei ght compared with the control group. This avian model of cellulitis an d other lesions will be useful for studying the development of vaccina tion strategies For E. coli in broilers.