Background The surrounding areas of the middle Mekong basin, particularly along the border between Thailand and Lao People’s Democratic Republic (Lao PDR), are high-risk areas for many livestock-associated foodborne illnesses, especially salmonellosis. This study aimed to determine the prevalence and characteristics of Salmonella spp. contamination in pork, beef and chicken meats sold at retail markets in the Thailand-Laos border area surrounding the Thai-Lao Friendship Bridge I from January to May 2019. We focused on the prevalent serotypes, antimicrobial susceptibility profiles and the multilocus sequence type (MLST) genotypes of the collected Salmonella strains. Results From a total of 370 meat samples collected, 63% were positive for Salmonella, with the prevalence of 73%, 60% and 56% from pork, beef and chicken meat samples, respectively. Of all the positive samples, 53 serotypes were identified. Of these, Salmonella enterica serovar London accounted for the majority (27%), followed by serovars Corvallis (14%), and Rissen (6%). Resistance against tetracycline was found at the highest frequency (50%), followed by ampicillin (35%) and sulfamethoxazole-trimethoprim (28%). MLST revealed no evidence of shared genetic relatedness of Salmonella at retail sites among Thailand-Laos border zone. However, a diverse range of Salmonella genotypes were spread over the area. Besides, the persistence of the residential pathogen and sharing of the supply route within-country can be inferred. Conclusions Given the high levels of contamination of retail meats, regular disinfecting of all working areas and quality control checking at pre-retail stage must be applied to reduce the transmission of Salmonella and other foodborne pathogens to consumers. The findings of this study will make a significant contribution to the current understanding of Salmonella epidemiology to enhance food security in the region.

中文翻译：

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沙门氏菌跨界传播的分子证据。在湄公河流域中部地区零售市场出售的肉类中

背景 湄公河流域中部的周边地区，特别是泰国和老挝人民民主共和国 (Lao PDR) 之间的边境地区，是许多与牲畜相关的食源性疾病，尤其是沙门氏菌病的高风险地区。本研究旨在确定沙门氏菌属的流行率和特征。2019 年 1 月至 2019 年 5 月，在泰老友谊大桥 I 周边的泰老边境地区零售市场销售的猪肉、牛肉和鸡肉的污染情况。我们重点研究了流行的血清型、抗菌药物敏感性概况和多位点序列类型（MLST ) 收集的沙门氏菌菌株的基因型。结果在共采集的370份肉类样本中，沙门氏菌阳性率为63%，猪肉、牛肉和鸡肉样本的患病率分别为73%、60%和56%。在所有阳性样本中，鉴定出 53 种血清型。其中，肠沙门氏菌伦敦血清型占多数（27%），其次是Corvallis血清型（14%）和Rissen血清型（6%）。对四环素的耐药率最高（50%），其次是氨苄青霉素（35%）和磺胺甲恶唑-甲氧苄啶（28%）。MLST 没有发现泰国-老挝边境地区零售场所存在沙门氏菌遗传相关性的证据。然而，各种各样的沙门氏菌基因型分布在该地区。此外，可以推断出居民病原体的持续存在和国内供应路线的共享。结论 鉴于零售肉类的高度污染，必须对所有工作区域进行定期消毒并在零售前阶段进行质量控制检查，以减少沙门氏菌和其他食源性病原体向消费者的传播。这项研究的结果将为当前对沙门氏菌流行病学的理解做出重大贡献，以加强该地区的粮食安全。