VISAVET Health Surveillance Centre, Universidad Complutense, Madrid, Spain.
Department of Veterinary Medicine, College of Veterinary Medicine, National Chung Hsing University, Taichung City, Taiwan.
BMC Vet Res. 2022 Sep 3;18(1):333. doi: 10.1186/s12917-022-03377-3.
Swine are considered a major source of foodborne salmonellosis, a public health issue further complicated by the circulation of multidrug-resistant Salmonella strains that threaten the safety of the food chain. The current study aimed to identify patterns that can help to understand the epidemiology of antimicrobial resistance (AMR) in Salmonella in pigs in Spain through the application of several multivariate statistical methods to data from the AMR national surveillance programs from 2001 to 2017.
A total of 1,318 pig Salmonella isolates belonging to 63 different serotypes were isolated and their AMR profiles were determined. Tetracycline resistance across provinces in Spain was the highest among all antimicrobials and ranged from 66.7% to 95.8%, followed by sulfamethoxazole resistance (range: 42.5% - 77.8%), streptomycin resistance (range: 45.7% - 76.7%), ampicillin resistance (range: 24.3% - 66.7%, with a lower percentage of resistance in the South-East of Spain), and chloramphenicol resistance (range: 8.5% - 41.1%). A significant increase in the percentage of resistant isolates to chloramphenicol, sulfamethoxazole, ampicillin and trimethoprim from 2013 to 2017 was observed. Bayesian network analysis showed the existence of dependencies between resistance to antimicrobials of the same but also different families, with chloramphenicol and sulfamethoxazole in the centre of the networks. In the networks, the conditional probability for an isolate susceptible to ciprofloxacin that was also susceptible to nalidixic acid was 0.999 but for an isolate resistant to ciprofloxacin that was also resistant to nalidixic acid was only 0.779. An isolate susceptible to florfenicol would be expected to be susceptible to chloramphenicol, whereas an isolate resistant to chloramphenicol had a conditional probability of being resistant to florfenicol at only 0.221. Hierarchical clustering further demonstrated the linkage between certain resistances (and serotypes). For example, a higher likelihood of multidrug-resistance in isolates belonging to 1,4,[5],12:i:- serotype was found, and in the cluster where all isolates were resistant to tetracycline, chloramphenicol and florfenicol, 86.9% (n = 53) of the isolates were Typhimurium.
Our study demonstrated the power of multivariate statistical methods in discovering trends and patterns of AMR and found the existence of serotype-specific AMR patterns for serotypes of public health concern in Salmonella isolates in pigs in Spain.
猪被认为是食源性沙门氏菌病的主要来源，这是一个公共卫生问题，由于多药耐药沙门氏菌菌株的传播，进一步复杂化，这些菌株威胁着食物链的安全。本研究旨在通过应用几种多变量统计方法，分析 2001 年至 2017 年抗微生物药物耐药性（AMR）国家监测计划的数据，了解西班牙猪源沙门氏菌 AMR 的流行病学模式。
共分离出 1318 株猪源沙门氏菌，属于 63 种不同血清型，并确定了其 AMR 特征。在西班牙各省，四环素耐药性是所有抗菌药物中最高的，范围为 66.7%至 95.8%，其次是磺胺甲恶唑耐药性（范围为 42.5%至 77.8%）、链霉素耐药性（范围为 45.7%至 76.7%）、氨苄西林耐药性（范围为 24.3%至 66.7%，西班牙东南部的耐药率较低）和氯霉素耐药性（范围为 8.5%至 41.1%）。从 2013 年到 2017 年，观察到对氯霉素、磺胺甲恶唑、氨苄西林和甲氧苄啶的耐药分离株的百分比显著增加。贝叶斯网络分析表明，同一类和不同类抗菌药物的耐药性之间存在依赖性，氯霉素和磺胺甲恶唑位于网络中心。在网络中，对环丙沙星敏感且对萘啶酸敏感的分离株的条件概率为 0.999，但对环丙沙星耐药且对萘啶酸耐药的分离株的条件概率仅为 0.779。对氟苯尼考敏感的分离株预计对氯霉素敏感，而对氯霉素耐药的分离株对氟苯尼考耐药的条件概率仅为 0.221。层次聚类进一步证明了某些耐药性（和血清型）之间的联系。例如，发现 1、4、[5]、12:i:-血清型的分离株更有可能具有多药耐药性，在所有分离株均对四环素、氯霉素和氟苯尼考耐药的聚类中，86.9%（n=53）的分离株为鼠伤寒沙门氏菌。
本研究表明，多变量统计方法在发现 AMR 趋势和模式方面具有强大的作用，并发现了西班牙猪源沙门氏菌分离株中与公共卫生相关血清型的特定血清型 AMR 模式的存在。
