Laboratorio de Diagnóstico e Investigaciones Bacteriológicas, Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, La Plata 1900, Argentina.
Foodborne Pathog Dis. 2009 Oct;6(8):965-72. doi: 10.1089/fpd.2008.0239.
The aim of this surveillance was to study both Salmonella spp. shedding patterns and the time course of serological response in farrow-to-finish reared pigs from a subclinically infected farm. Antimicrobial resistance profile, molecular subtyping, and the relationship among the isolates were determined by pulsed-field gel electrophoresis (PFGE). A farrow-to-finish farm of 6000 sows, with a history of Salmonella Typhimurium septicemia, was selected. A longitudinal bacteriological and serological study was conducted in 25 sows before farrowing (M/S1) and in 50 offspring at 21 (M/S2), 35 (M/S3), 65 (M/S4), 86 (M/S5), 128 (M/S6), and 165 (M/S7) days of age. Serum antibodies were tested using Herdcheck((R)) Swine Salmonella antibody test kit (Idexx Laboratories, ME). Bacteria were isolated from pooled fecal samples. Suspected isolates were confirmed by conventional biochemical assays, and those identified as Salmonella spp. were serotyped. A variation between seropositive percentages and positive fecal samples was observed. Serologically positive pigs decreased from S1 to S4, and subsequently increased from S4 to S7. The percentages of fecal positive culture increased from M1 to M3, and then declined in M4, increased in M5, and were negative in M6 and M7. In the study three serovars, Salmonella 3,10:e,h:-, Salmonella Muenster, and Salmonella Bovismorbificans, were identified with low pathogenicity for swine. Three multidrug resistance strains (one belonged to Salmonella 3,10:e,h:- and two belonged to Salmonella Muenster) were found. PFGE results showed three different but closely related patterns among the 13 isolates of Salmonella Bovismorbificans, and two patterns for the three Salmonella Muenster and Salmonella 3,10:e,h:- isolates. This longitudinal study established critical points of Salmonella spp. infection in the farm and the production stages, where appropriate control measures must be taken. PFGE showed clonal relationships in each serovar. Antibiotic resistance profiles should be periodically included due to public health concerns.
本监测旨在研究从一个亚临床感染农场育肥至出栏的猪群中沙门氏菌的排放模式和血清学反应的时间过程。通过脉冲场凝胶电泳（PFGE）确定了抗生素耐药谱、分子亚型以及分离株之间的关系。选择了一个具有 6000 头母猪的育肥至出栏农场，该农场曾有鼠伤寒沙门氏菌败血症的历史。对 25 头母猪进行了产前（M/S1）和 50 头后代在 21 天（M/S2）、35 天（M/S3）、65 天（M/S4）、86 天（M/S5）、128 天（M/S6）和 165 天（M/S7）龄时的纵向细菌学和血清学研究。使用 Herdcheck((R))猪沙门氏菌抗体检测试剂盒（Idexx Laboratories，ME）检测血清抗体。从混合粪便样本中分离细菌。通过常规生化检测确认疑似分离株，对鉴定为沙门氏菌的分离株进行血清分型。观察到血清阳性百分比和阳性粪便样本之间存在差异。血清学阳性猪从 S1 到 S4 减少，然后从 S4 到 S7 增加。从 M1 到 M3，粪便阳性培养的百分比增加，然后在 M4 下降，在 M5 增加，在 M6 和 M7 中为阴性。在研究中，鉴定出三种低毒力的血清型，即 3,10:e,h:-沙门氏菌、Muenster 沙门氏菌和 Bovismorbificans 沙门氏菌。发现了三种多药耐药菌株（一种属于 3,10:e,h:-沙门氏菌，两种属于 Muenster 沙门氏菌）。PFGE 结果显示，13 株 Bovismorbificans 沙门氏菌中有 3 种不同但密切相关的模式，3 株 Muenster 沙门氏菌和 3,10:e,h:-沙门氏菌中有 2 种模式。这项纵向研究确定了农场和生产阶段沙门氏菌感染的关键点，必须在这些阶段采取适当的控制措施。PFGE 显示每个血清型都存在克隆关系。由于公共卫生问题，应定期包括抗生素耐药谱。
