Prevalence and antimicrobial resistance of Salmonella enterica subspecies enterica serovar Enteritidis isolated from broiler chickens in Shandong Province, China, 2013-2018

Salmonella is a major zoonotic foodborne pathogen that persists on poultry farms worldwide. The present study aimed to survey the prevalence of Salmonella and antimicrobial resistance of Salmonella enterica serovar Enteritidis (S. Enteritidis) recovered from broiler chickens in Shandong Province, China. A total of 280 Salmonella isolates were identified from 923 broiler chicken samples between 2013 and 2018. Among the isolates, S. Enteritidis (n = 128, 45.7%) was the predominant serovar, and high antimicrobial resistance rates to piperacillin (PIP) (n = 123, 96.1%), ampicillin (AM) (n = 122, 95.3%), nitrofurantoin (FT) (n = 106, 96.1%), and tetracycline (TE) (n = 93, 72.7%) were observed in S. Enteritidis. A total of 96 (75.0%) S. Enteritidis isolates presented with multidrug resistance, the most frequent of which were the combination of AM, PIP, TE, and FT. Resistance to fluoroquinolone tended to increase during 2013 to 2018. Our findings provide important and updated information about the baseline antimicrobial-resistant data for food safety and a risk assessment of S. Enteritidis from broiler chickens in Shandong Province and will be helpful for future surveillance activities to ensure the safety of the chicken supply.