Cui Lulu, Liu Qingxiao, Jiang Zhiyu, Song Yan, Yi Shoujing, Qiu Jianhua, Hao Guijuan, Sun Shuhong
Department of Preventive Veterinary Medicine, College of Animal Science and Technology, Shandong Agricultural University, Tai'an, China.
Front Vet Sci. 2021 Mar 23;8:607491. doi: 10.3389/fvets.2021.607491. eCollection 2021.
is a common food-borne Gram-negative pathogen with multiple serotypes. Pullorum disease, caused by Pullorum, seriously threatens the poultry industry. Many previous studies were focused on the epidemiological characteristics of infections in conventional antibiotic use poultry. However, little is known about infections in chicken flocks fed on antibiotic-free diets. Herein, we investigated and compared infections in three Chinese native breeders fed on antibiotic-free diets, including the Luhua, Langya, and Qingjiaoma chickens, and one conventional breeder, the Bairi chicken, via analyzing 360 dead embryos in 2019. The results showed that the main serotypes detected in a total of 155 isolates were . Pullorum (82.6%) and . Enteritidis (17.4%). Coinfection with two serotypes of was specifically found in Bairi chicken. The sequence type (ST) in . Pullorum was ST92 ( = 96) and ST2151 ( = 32), whereas only ST11 ( = 27) was found in . Enteritidis. The isolates from three breeder flocks fed on antibiotic-free diets exhibited phenotypic heterogeneity with a great variety of drug resistance spectrum. Most of the isolates among three chicken breeds Luhua (64.9%, 50/77), Langya (60%, 12/20) and Qingjiaoma (58.3%, 7/12) fed on antibiotic-free diets were resistant to only one antibiotic (erythromycin), whereas the rate of resistance to one antibiotic in conventional Bairi chicken isolates was only 4.3% (2/46). The multidrug-resistance rate in isolates from layer flocks fed on antibiotic-free diets (20.2%, 22/109) was significantly ( < 0.0001) lower than that from chickens fed on conventional diets (93.5%, 43/46). However, high rate of resistance to erythromycin (97.4%100%) and streptomycin (26%41.7%) were also found among three breeder flocks fed on antibiotic-free diets, indicating resistance to these antibiotics likely spread before antibiotic-free feeding in poultry farms. The findings of this study supplement the epidemiological data of salmonellosis and provide an example of the characteristics of in the chicken flocks without direct antibiotic selective pressure.
是一种常见的食源性病原体，革兰氏阴性，有多种血清型。由鸡白痢沙门氏菌引起的鸡白痢严重威胁着家禽业。以往许多研究都集中在使用传统抗生素的家禽感染的流行病学特征上。然而，对于以无抗生素日粮喂养的鸡群中的感染情况却知之甚少。在此，我们通过分析2019年的360个死胚，调查并比较了三种以无抗生素日粮喂养的中国本土鸡品种（芦花鸡、琅琊鸡和青脚麻鸡）以及一种传统鸡品种（百里鸡）中的感染情况。结果显示，在总共155株分离株中检测到的主要血清型为鸡白痢沙门氏菌（82.6%）和肠炎沙门氏菌（17.4%）。在百里鸡中特别发现了两种血清型的共感染情况。鸡白痢沙门氏菌的序列类型（ST）为ST92（n = 96）和ST2151（n = 32），而肠炎沙门氏菌中仅发现了ST11（n = 27）。来自三个以无抗生素日粮喂养的种鸡群的分离株表现出表型异质性，耐药谱种类繁多。在以无抗生素日粮喂养的芦花鸡（64.9%，50/77）、琅琊鸡（60%，12/20）和青脚麻鸡（58.3%，7/12）这三个鸡品种中，大多数分离株仅对一种抗生素（红霉素）耐药，而在传统的百里鸡分离株中，对一种抗生素的耐药率仅为4.3%（2/46）。以无抗生素日粮喂养的蛋鸡群分离株中的多重耐药率（20.2%，22/109）显著低于（P < 0.0001）以传统日粮喂养的鸡群（93.5%，4
