Disease caused by antibiotic-resistant Salmonella is a serious clinical problem that poses a great threat to public health. The present study is aimed at assessing differences in bacterial kinetics with different antibiotic resistance profiles under environmental stress and at developing microbial tolerance models in lettuce during storage from 4 to 36°C. The drug-resistance phenotypes of 10 Salmonella Typhimurium (S. Typhimurium) isolates were examined using the broth microdilution method. The results of 10 S. Typhimurium isolates in the suspensions showed that a slow trend towards reduction of drug-sensitive (DS) isolates in relation to the others though without statistical difference. Compared to DS S. Typhimurium SA62, greater bacterial reduction was observed in multidrug-resistant (MDR) S. Typhimurium HZC3 during lettuce storage at 4°C (). It was likely that a cross-response between antibiotic resistance and food-associated stress tolerance. The greater growth in lettuce at 12°C was observed for DS S. Typhimurium SA62 compared to MDR S. Typhimurium HZC3 and was even statistically different (), while no significant difference was observed for bacterial growth between MDR S. Typhimurium HZC3 and DS S. Typhimurium SA62 strains in lettuce storage from 16 to 36°C (). The goodness-of-fit indices indicated the Log-linear primary model provided a satisfactory fit to describe the MDR S. Typhimurium HZC3 and DS S. Typhimurium SA62 survival at 4°C. A square root secondary model could be used to describe the effect of temperature (12, 16, 28, and 36°C) on the growth rates of S. Typhimurium HZC3 (, ) and S. Typhimurium SA62 (, ) derived from the Huang primary model. It was necessary to pay attention to the tolerance of antibiotic resistant bacteria under environmental stress, and the generated models could provide parts of the input data for microbial risk assessment of Salmonella with different antibiotic resistance profile in lettuce.

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不同抗生素耐药性沙门氏菌抗应激能力的评价

耐抗生素沙门氏菌引起的疾病是一个严重的临床问题，对公众健康构成巨大威胁。本研究旨在评估环境压力下具有不同抗生素耐药性的细菌动力学差异，并开发生菜在 4 至 36°C 储存期间的微生物耐受模型。采用肉汤微量稀释法检测了 10 株鼠伤寒沙门氏菌 ( S. Typhimurium)的耐药表型。悬浮液中 10 个鼠伤寒沙门氏菌分离株的结果表明，与其他分离株相比，药物敏感 (DS) 分离株的减少趋势缓慢，但没有统计学差异。与 DS相比. Typhimurium SA62，在耐多药（MDR）沙门氏菌中观察到更大的细菌减少。生菜在 4°C 下储存期间的鼠伤寒 HZC3 (）。抗生素耐药性和与食物相关的压力耐受性之间可能存在交叉反应。对于 DS S观察到在 12°C 时生菜的更大生长。Typhimurium SA62 与 MDR S相比。Typhimurium HZC3 甚至有统计学差异（)，而 MDR S之间的细菌生长没有观察到显着差异。鼠伤寒 HZC3 和 DS S。生菜贮藏温度为 16 至 36°C 的鼠伤寒 SA62 菌株（）。拟合优度指数表明对数线性主模型提供了令人满意的拟合来描述MDR S。鼠伤寒 HZC3 和 DS S。Typhimurium SA62 在 4°C 下存活。平方根二级模型可用于描述温度（12、16、28 和 36°C）对S生长速率的影响。鼠伤寒 HZC3 (, )和S。鼠伤寒SA62（, )源自 Huang 初级模型。需要关注抗生素耐药菌在环境胁迫下的耐受性，生成的模型可以为生菜中不同抗生素耐药性沙门氏菌的微生物风险评估提供部分输入数据。