Prevalence and Characteristics ofSalmonellaIsolated from Free-Range Chickens in Shandong Province, China

Abstract

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.

Antibiogram and genetic diversity ofSalmonella entericawith zoonotic potential isolated from morbid native chickens and pigeons in Egypt

“…Therefore, harbouring Salmonella pathogens in theses reservoirs may constitute a considerable hazard to human and animal health. Salmonella was detected in 14Á3% of morbid Fayoumi chickens in this study, which was consistent with a report (12Á7%) on Salmonella in free-range chickens in China (Zhao et al 2016). Higher (50%) and lower (5Á6%) prevalence has been reported in free-range-reared chickens in the United States by Melendez et al (2010) and Alali et al (2010), respectively.…”

Prevalence of Salmonella Isolates and Their Distribution Based on Whole-Genome Sequence in a Chicken Slaughterhouse in Jiangsu, China

“…A study from Brazil demonstrated that the prevalence of Salmonella was only 3.6% in a chicken slaughterhouse (25). In China, the isolation rate of Salmonella was 12.7% in chickens in Shandong province (13), while no Salmonella was detected in a chicken slaughterhouse in Sichuan province (26). However, in Guangdong province, the prevalence of Salmonella in chicken and pork meat at retail markets was 63.6 and 73.1%, respectively, and 62.86% of samples from slaughterhouse were detected to be positive for Salmonella (27,28).…”

“…Another research showed that the MLST of S. Enteritidis identified from humans was ST11 (12). The most common serotypes from the chicken were S. Enteritidis, followed by S. Indiana and S. Typhimurium, while the predominant MLST types were ST11, ST17, and ST19 in Shandong province of China (13,14).…”

Antibiogram Profiles and Risk Factors for Multidrug Resistance of Salmonella enterica Recovered from Village Chickens (Gallus gallus domesticus Linnaeus) and Other Environmental Sources in the Central and Southern Peninsular Malaysia

“…Other studies around the world have shown the presence of antimicrobial resistant Salmonella recovered from backyard or free-range chickens. In most of these studies, resistance was demonstrated against ampicillins and tetracyclines [ 32 , 33 , 34 , 35 , 36 ]. Eight (23.5%) of the Salmonella isolates in this study were resistant to three or more antimicrobial agents (MDR; Table 3 ).…”