Characterization of Salmonella from Commercial Egg-Laying Hen Farms in a Central Region of Colombia.

Abstract

Salmonellosis affects humans more frequently than any other foodborne disease, and it causes severe economic losses in the poultry industry. A cross-sectional study was carried out to estimate the prevalence of Salmonella spp. in laying hen farms in the Tolima region of Colombia. Fifteen egg-laying hen farms were sampled, and a total of 589 samples were cultured to isolate Salmonella spp. A total of 14 isolates of Salmonella spp. were recovered from five farms, resulting in a prevalence of 33.33% (95%, confidence interval = 14%-53%) at the farm level. Salmonella spp. were recovered from eggshells (57.15%, n = 8), feed (28.57%, n = 4), and environmental samples (14.29%, n = 2). Farm practices, such as the milling of feed (odds ratio [OR] = 24) and the storage of eggs in the henhouses (OR = 11.25), in addition to the feed type (OR = 7.64) and the use of bamboo for construction of the facility (OR = 5.24), were identified as risk factors for Salmonella spp. The 14 isolates were identified as Salmonella Enteritidis (n = 6) and Salmonella Shannon (n = 8), and both serovars were resistant to a number of antibiotics. Pulsed-field gel electrophoresis presented three different XbaI macrorestriction patterns. The Salmonella Enteritidis isolates all presented a single pattern, whereas the Salmonella Shannon isolates were grouped into two distinct patterns. The results indicate that Salmonella spp. could be recovered from various sources at laying hen farms, and eggshell contamination is a particular concern.