SUMMARY
Since 2018, the Poultry Diagnostic and Research Center at the University of Georgia has observed an increased, yet sporadic, incidence of Castellaniella spp. isolation from commercial broiler breeders from various integrators. To our knowledge, this organism had never been reported in commercial poultry. The commonalities among cases were a presenting complaint of increased mortality, lameness, and swollen wattles. Postmortem examination revealed hock synovitis, swollen wattles, inflammation, and marked subcutaneous mandibular edema that extended along the ventral neck. Swabs were taken from affected tissues for conventional aerobic culture, revealing a gram-negative bacillus organism that produced very small, almost pinpoint, clear colonies on 5% sheep blood agar but no growth on MacConkey agar. The organism was characterized as strongly oxidase positive and indole negative. Further identification involving 16S rRNA sequencing confirmed the unknown organism as Castellaniella spp. The recurring isolation of this organism warrants further investigation into factors such as source, mode of transmission, primary pathogen status, prevention, and treatment options. The animal health community should be aware of the potential of Castellaniella spp. to infect chickens, along with its clinical characteristics and microbiologic presentation.