Isolation of Salmonella spp from the environment of dairies without any history of clinical salmonellosis

OBJECTIVE: To determine whether Salmonella spp could be isolated from the environment of free stall dairies in Wisconsin without any history of clinical salmonellosis and determine the serotype and antimicrobial susceptibility of any Salmonella isolates recovered from the environment. DESIGN: Cross-sectional study. STUDY POPULATION: 20 free stall dairies with no history of clinical salmonellosis. PROCEDURES: Dairy owners completed a questionnaire regarding management and production practices. Multiple swab samples were obtained from throughout the free stall facilities and submitted for bacterial culture for Salmonella spp. Odds ratios were calculated to compare herd-level risk factors between dairies from which Salmonella organisms were isolated and herds from which Salmonella organisms were not isolated. RESULTS: Salmonella organisms were isolated from 9 of the 20 (45%) dairies. Salmonella serotype Meleagridis was isolated from 4 dairies, S. Meleagridis and S. Kentucky were isolated from 2 dairies, S. Meleagridis and S. Cyprus were isolated from 1 dairy, S. Cerro was isolated from 1 dairy, and S. Corvallis was isolated from 1 dairy. All isolates were susceptible to all antimicrobial agents tested. None of the potential risk factors analyzed demonstrated a significant association with an increased likelihood of isolating Salmonella spp. CONCLUSIONS AND CLINICAL RELEVANCE: Environmental Salmonella contamination was demonstrated on free stall dairies with no history of clinical salmonellosis.