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BioMed Research International
Volume 2016 (2016), Article ID 8183931, 6 pages
Research Article

Prevalence and Characteristics of Salmonella Isolated from Free-Range Chickens in Shandong Province, China

1College of Animal Science and Technology, Shandong Agricultural University, Tai’an 271000, China
2College of Life Sciences, Taishan Medical University, Tai’an 271000, China

Received 7 May 2016; Accepted 24 August 2016

Academic Editor: Yi-Ping Liu

Copyright © 2016 Xiaonan Zhao et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Compared with chickens raised in intensively managed breeding farms, free-range chickens in China are quite popular due to lower breeding density and less antibiotics usage. However, investigations about Salmonella enterica from free-range chickens are quite rare. The aim of the present study was to investigate prevalence and characteristics of Salmonella in free-range chickens in Shandong province, China. During the period of August and November 2015, 300 fresh fecal swabs from different broilers in three free-range chicken farms (100 samples per farm) were collected to isolate Salmonella, and then these isolates were subjected to serotyping, antibiotic sensitivity testing, enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR), and multilocus sequence typing (ST). A total of 38 Salmonella isolates (38/300, 12.7%) were recovered. The most common serotype was Enteritidis (81.6%), followed by Indiana (13.2%) and Typhimurium (5.3%). Twenty-two out of 38 isolates (57.9%) were resistant to ampicillin, the highest resistance rate, but resistance rates to cefazolin, cefotaxime, and ceftazidime were only 7.9%. The multidrug resistance (MDR) rate was 26.3%. Additionally, the Salmonella isolates could be classified into 25 genotypes by ERIC-PCR and were divided into three ST types (ST11, ST17, and ST19), with ST11 the highest isolation rate (81.6%). In summary, as with other poultry, free-ranging chickens may also serve as potential reservoir for antibiotic resistant Salmonella, thereby posing a threat to public health.