Barbour E K, Jurdi L H, Talhouk R, Qatanani M, Eid A, Sakr W, Bouljihad M, Spasojevic R
Animal Science Department, Faculty of Agricultural and Food Sciences, American University of Beirut, Lebanon.
Rev Sci Tech. 1999 Dec;18(3):710-8. doi: 10.20506/rst.18.3.1184.
This study investigates the first emergence of Salmonella Enteritidis outbreaks among chickens in the Lebanon and identifies the epidemiological markers of selected recovered Enteritidis strains. In addition, the authors evaluate a competitive exclusion approach to control infection in broiler chickens by Enteritidis organisms which possess the prevalent identified markers. The basic procedure in this investigation involved recording signs and lesions in eleven broiler chicken flocks on eleven farms, and culturing livers, spleens, and caeca of ten randomly selected birds per flock for Salmonella isolation and serotyping. Furthermore, culturing for Salmonella and serotyping was attempted from the livers, spleens, caeca and oviduct swabs of ten hens in four broiler breeder flocks which provided hatching eggs for the broilers under study. The identification of epidemiological markers in recovered S. Enteritidis included the determination of drug-resistance patterns and plasmid profiling. The competitive exclusion was evaluated by spraying the microflora on day-old broilers in the hatchery, followed by a controlled oral challenge at three days of age, with 2.85 x 10(5) colony-forming units of S. Enteritidis organisms per bird. Exclusion was evaluated by culturing for S. Enteritidis in anal swabs, spleens, livers, and caeca of individual challenged birds treated with the microflora and in untreated challenged birds. A total of 112 invasive S. Enteritidis strains were recovered on eleven farms from individual organs of broiler chickens with typical signs and lesions of salmonellosis. The prevalent resistance to drugs in such strains was to furaltadone and gentamycin, a marker identified in 93 strains (83%), recovered from nine out of eleven farms. The same resistance pattern was present in S. Enteritidis strains recovered from breeders on one out of four farms. The prevalent plasmid profile in nine S. Enteritidis organisms selected randomly from a pool of 93 strains (one per each of the nine broiler farms) was 14.1 kilobases (kb) and approximately 50.0 kb, a typical pattern to that identified in S. Enteritidis organisms recovered from oviducts of breeders on one out of four breeder farms. The exclusion significantly reduced cumulative mortality in birds of up to 45 days of age by 3.93%, in comparison to that observed in untreated challenged birds (P < 0.05). At 45 days of age, exclusion resulted in a 15.6% reduction in the percentage infection rate by S. Enteritidis in spleens or livers and a 34.4% reduction in the percentage infection rate of the caeca (P < 0.05).
本研究调查了黎巴嫩鸡群中首次出现的肠炎沙门氏菌疫情，并确定了部分分离出的肠炎沙门氏菌菌株的流行病学标记。此外，作者评估了一种竞争性排斥方法，以控制携带已确定流行标记的肠炎沙门氏菌对肉鸡的感染。本调查的基本程序包括记录11个农场中11个肉鸡群的症状和病变，并对每个鸡群随机选取的10只鸡的肝脏、脾脏和盲肠进行培养，以分离沙门氏菌并进行血清分型。此外，还尝试从为所研究的肉鸡提供种蛋的4个肉种鸡群中10只母鸡的肝脏、脾脏、盲肠和输卵管拭子中培养沙门氏菌并进行血清分型。对分离出的肠炎沙门氏菌的流行病学标记鉴定包括耐药模式的测定和质粒图谱分析。通过在孵化场对一日龄肉鸡喷洒微生物菌群来评估竞争性排斥，随后在三日龄时进行可控口服攻毒，每只鸡接种2.85×10⁵个肠炎沙门氏菌菌落形成单位。通过对用微生物菌群处理的个体攻毒鸡和未处理的攻毒鸡的肛门拭子、脾脏、肝脏和盲肠进行肠炎沙门氏菌培养来评估排斥效果。在11个农场中，从出现沙门氏菌病典型症状和病变的肉鸡个体器官中总共分离出112株侵袭性肠炎沙门氏菌菌株。这些菌株中普遍的耐药药物是呋喃他酮和庆大霉素，在从11个农场中的9个农场分离出的93株菌株（83%）中鉴定出了这一标记。从4个农场中的1个农场的种鸡中分离出的肠炎沙门氏菌菌株也呈现相同的耐药模式。从93株菌株（9个肉鸡农场各1株）中随机选取的9株肠炎沙门氏菌的普遍质粒图谱为14.1千碱基（kb）和约50.0 kb，这与从4个种鸡农场中的1个农场的种鸡输卵管中分离出的肠炎沙门氏菌的典型图谱一致。与未处理的攻毒鸡相比，排斥显著降低了45日龄以内鸡的累计死亡率，降低了3.93%（P<0.05）。在45日龄时，排斥使脾脏或肝脏中肠炎沙门氏菌的感染率百分比降低了15.6%，盲肠感染率百分比降低了34.4%（P<0.05）。
