Prevalence and risk factors for Salmonella spp. colonization in broiler flocks in Shiraz, southern Iran

Salmonella spp. are important food borne pathogens worldwide that frequently infect poultry flocks. This cross-sectional study was conducted to determine the prevalence of Salmonella spp. colonization in broiler flocks in Shiraz (southern Iran) and to find the possible association of infection status with some potential risk factors including vaccination program and use of antibiotics. During October ۲۰۰۹ to April ۲۰۱۰, a total of ۴۰ broiler flocks were selected in slaughterhouse and ۲۰ cloacae contents were collected from each flock. Every five cloacae contents were pooled and investigated for Salmonella spp. using appropriate culture methods. The flock was considered positive if any of the pooled samples turned positive in culture. Statistical analysis was performed using multiple logistic regression. Nine out of ۴۰ flocks (۲۲.۵۰%, ۹۵% CI: ۹-۳۶) were positive for Salmonella spp. colonization. Nearly ۷۵.۰۰% of flock owners reported that they used antibiotics during production period, more frequently fluoroquinolones, combination of trimethoprim-sulfonamides (TMP/SU) and tetracycline. Nearly ۶۰.۰۰% of the flocks which had used TMP/SU were positive for Salmonella spp. compared with ۱۰.۰۰% of the flocks which did not use this antibiotic (p = ۰.۰۰۶). Increasing flock age was associated with a decreased chance of Salmonella spp. detection (p = ۰.۰۰۳). In flocks which received infectious bronchitis vaccine, ۳۶.۰۰% were positive for Salmonella spp. whereas this was ۱۵.۰۰% for flocks which did not receive this vaccine (p = ۰.۰۸). Careful monitoring of antibiotics use and further studies to determine the most appropriate vaccination program in the field is recommended.

کلیدواژه ها:

Antibiotic ، Broiler flocks ، Iran ، Salmonella ، Vaccination