Giacomini Enrico, Gasparrini Sara, Lazzaro Massimiliano, Scali Federico, Boniotti Maria Beatrice, Corradi Attilio, Pasquali Paolo, Alborali Giovanni Loris
Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna [Experimental Zooprophylactic Institute of Lombardy and Emilia Romagna] "Bruno Ubertini", Via Bianchi 7/9, 25124, Brescia, Italy.
Department of Veterinary Sciences, University of Parma, Parma, Italy.
BMC Vet Res. 2018 Jan 10;14(1):10. doi: 10.1186/s12917-017-1328-5.
Direct and indirect contact among animals and holdings are important in the spread of Brachyspira hyodysenteriae. The objective of this study was to investigate the role of slaughterhouse vehicles in spreading B. hyodysenteriae between unconnected farms.
Multilocus sequence typing (MLST) and Multiple Locus Variable number tandem repeat Analysis (MLVA) were used to characterize B. hyodysenteriae strains isolated from trucks. Before cleaning, 976 batches of finishing pigs transported by 174 trucks from 540 herds were sampled. After cleaning, 763 of the 976 batches were also sampled. Sixty-one of 976 and 4 of 763 environmental swabs collected from trucks before and after cleaning and disinfection operations, respectively, were positive for B. hyodysenteriae. The 65 isolates in this study originated from 48 farms. Trucks were classified into five categories based on the number of visited farms as follows: category 1: 1-5 farms, category 2: 6-10 farms, category 3: 11-15 farms, category 4: 16-20 farms, category 5: >21 farms. Although the largest number of vehicles examined belonged to category 1, the highest percentage of vehicles positive for B. hyodysenteriae was observed in categories 3, 4 and 5. Specifically, 90.9% of trucks belonging to category 5 were positive for B. hyodysenteriae, followed by categories 4 and 3 with 85.7% and 83.3%, respectively. The results of MLST and MLVA suggest that trucks transporting pigs from a high number of farms also play a critical role in spreading different B. hyodysenteriae genetic profiles. STVT 83-3, which seems to be the current dominant type in Italy, was identified in 56.25% of genotyped isolates. The genetic diversity of isolated strains from trucks was high, particularly, in truck categories 3, 4 and 5. This result confirmed that MLST and MLVA can support the study of epidemiological links between different B. hyodysenteriae farm strains.
This study highlights the potential role of shipments in B. hyodysenteriae spread. Moreover, it emphasizes the importance of strict vehicle hygiene practices for biosecurity programmes.
动物及养殖场之间的直接和间接接触在猪痢疾短螺旋体传播中很重要。本研究的目的是调查屠宰场车辆在未关联农场间传播猪痢疾短螺旋体中的作用。
采用多位点序列分型（MLST）和多位点可变数目串联重复序列分析（MLVA）对从卡车上分离的猪痢疾短螺旋体菌株进行特征分析。在清洗前，对来自540个猪群的174辆卡车运输的976批次育肥猪进行了采样。清洗后，对976批次中的763批次也进行了采样。分别从清洗和消毒操作前后的卡车上采集的976份和763份环境拭子中，有61份和4份猪痢疾短螺旋体呈阳性。本研究中的65株分离株来自48个农场。卡车根据访问的农场数量分为五类，如下：第1类：1 - 5个农场，第2类：6 - 10个农场，第3类：11 - 15个农场，第4类：16 - 20个农场，第5类：>21个农场。虽然检查的车辆中数量最多的属于第1类，但在第3、4和5类中观察到猪痢疾短螺旋体呈阳性的车辆百分比最高。具体而言，第5类卡车中有90.9%猪痢疾短螺旋体呈阳性，其次是第4类和第3类，分别为85.7%和83.3%。MLST和MLVA的结果表明，从大量农场运输猪的卡车在传播不同的猪痢疾短螺旋体基因谱方面也起着关键作用。在56.25%的基因分型分离株中鉴定出STVT 83 - 3，这似乎是意大利目前的主要类型。从卡车上分离的菌株的遗传多样性很高，特别是在第3、4和5类卡车中。这一结果证实，MLST和MLVA可支持研究不同猪痢疾短螺旋体农场菌株之间的流行病学联系。
本研究突出了运输在猪痢疾短螺旋体传播中的潜在作用。此外，强调了严格的车辆卫生措施对生物安全计划的重要性。
