Seixas Rui, Santos Tânia Raquel, Machado Jorge, Tavares Luís, Bernardo Fernando, Semedo-Lemsaddek Teresa, Oliveira Manuela
1 CIISA/Faculty of Veterinary Medicine, University of Lisbon , Lisbon, Portugal .
2 National Reference Laboratory of Gastrointestinal Infections, National Health Institute Doutor Ricardo Jorge , Lisbon, Portugal .
Foodborne Pathog Dis. 2016 Nov;13(11):633-641. doi: 10.1089/fpd.2016.2156. Epub 2016 Oct 21.
The increase in prevalence of Salmonella 1,4,[5],12:i:- related infections over the last few years has been considered a public health issue in many European countries, especially as this serovar may be associated with tetraresistance to ampicillin, streptomycin, sulfonamides, and tetracyclines (R-type ASSuT). Salmonella 1,4,[5],12:i:- isolates (n = 187) obtained by the Portuguese National Laboratory from different sources, including human clinical cases (n = 170), veterinary (n = 10), environmental (n = 6), and food samples (n = 1), were collected from 15 districts between 2006 and 2011. All isolates were serotyped using the slide agglutination method and results were confirmed by multiplex PCR for the monophasic variant. From the confirmed Salmonella 1,4,[5],12:i:-, R-type ASSuT isolates were selected by disc diffusion and minimal inhibitory concentration (MIC) determination for further characterization by pulsed-field gel electrophoresis restriction with XbaI, virulence genes determination by PCR, additional antimicrobial resistance profiling by disc diffusion, and epidemiological distribution evaluation. Out of the 187 serotyped isolates, 133 were confirmed as Salmonella 1,4,[5],12:i:- with a R-type ASSuT occurrence of 61.7%. Distribution among Portuguese districts showed a higher percentage of reported cases in coastal areas, in particular, in Porto (24.8%), Setúbal (13.5%), and Aveiro (12.8%), probably due to the higher population density. Clonality analysis revealed a high diversity of pulsotypes with the majority of human salmonellosis cases being attributed to sporadic events. All isolates harbored 14 out of the 18 virulence genes evaluated and 87.8% of the isolates showed all the resistance genes frequently associated with the European clone, blaTEMsul2straA-straBtetB. This study shows that Salmonella 1,4,[5],12:i:- resistant isolates are widely distributed in Portugal. This may be related to a selective advantage offered by R-type ASSuT profile, the presence of multiple virulent features, including the ability to form biofilms, which along with a high diversity of pulsotypes may be responsible for the dissemination through the country.
在过去几年中，1,4,[5],12:i:- 相关的沙门氏菌感染患病率上升已被许多欧洲国家视为一个公共卫生问题，特别是因为这种血清型可能与对氨苄青霉素、链霉素、磺胺类药物和四环素的四重耐药性（R型ASSuT）有关。葡萄牙国家实验室从不同来源获得的1,4,[5],12:i:- 沙门氏菌分离株（n = 187），包括人类临床病例（n = 170）、兽医（n = 10）、环境（n = 6）和食品样本（n = 1），于2006年至2011年期间从15个地区收集。所有分离株均采用玻片凝集法进行血清分型，结果通过多重PCR对单相变体进行确认。从确认的1,4,[5],12:i:- 沙门氏菌中，通过纸片扩散法和最低抑菌浓度（MIC）测定选择R型ASSuT分离株，以通过XbaI脉冲场凝胶电泳限制性分析进行进一步表征，通过PCR测定毒力基因，通过纸片扩散法进行额外的抗菌药物耐药性分析，以及评估流行病学分布。在187个血清分型的分离株中，133个被确认为1,4,[5],12:i:- 沙门氏菌，R型ASSuT的发生率为61.7%。葡萄牙各地区的分布显示，沿海地区报告的病例百分比更高，特别是在波尔图（24.8%）、塞图巴尔（13.5%）和阿威罗（12.8%），这可能是由于人口密度较高。克隆性分析显示脉冲型具有高度多样性，大多数人类沙门氏菌病病例归因于散发性事件。所有分离株在评估的18个毒力基因中有14个，87.8%的分离株显示出所有与欧洲克隆相关的耐药基因，blaTEM、sul2、straA-straB、tetB。这项研究表明，1,4,[5],12:i:- 耐药性分离株在葡萄牙广泛分布。这可能与R型ASSuT谱提供的选择优势、多种毒力特征的存在有关，包括形成生物膜的能力，这与脉冲型的高度多样性一起可能是其在该国传播的原因。
