Abstract：
To study potential ramifications of antimicrobial resistance, we carried out adaptive laboratory evolution assays (ALE) to isolate three resistant variants (RVs) of Salmonella enterica Typhimurium, employing three different types of food preservation methods: 1) an emergent technology, plasma-activated water (PAW), leading to variant RV-PAW; a traditional method, heat, leading to variant RV-HT, and a natural antimicrobial compound, carvacrol, leading to variant RV-CAR. The variant resistant to plasma-activated water, RV-PAW, had mutations in rpoA and rpoD; it showed increased tolerance to heat in orange juice but ultimately did not pose a significant threat, as it exhibited a fitness cost at refrigeration temperature (8 °C), whereas its virulence against Caenorhabditis elegans decreased. The variant resistant to heat, RV-HT, had mutations in flhC, dnaJ: it exhibited a fitness cost at high growth temperatures (43 °C) and induced morphofunctional alterations in C. elegans. The variant resistant to carvacrol, RV-CAR, had mutations in sseG, flhA, wbaV, lon; this variant not only exhibited significantly higher thermotolerance in both laboratory media and food models but also effectively increased its growth fitness at refrigeration temperatures while retaining its virulence, evidenced by the highest percentage of Smurf phenotype in C. elegans. To address these challenges, we applied a process combining thermal treatment with citral, with the aim of leveraging the sublethal damage caused in RVs by heat treatments in orange juice. This approach achieves enhanced microbial inactivation without having to escalate the intensity of the thermal treatment. The result was particularly encouraging in the case of RV-CAR, the most challenging strain, for which we improved lethality by up to 3 log10 inactivation cycles.
摘要：
为了研究抗菌素耐药性的潜在后果，我们进行了适应性实验室进化分析（ALE），以分离出鼠伤寒沙门氏菌的三种抗性变体（RV），采用三种不同类型的食品保存方法：1)紧急技术，血浆活化水(PAW),导致变异的RV-PAW；一种传统的方法，热,导致变异的RV-HT，和一种天然的抗菌化合物，香芹酚,导致变型RV-CAR。抗血浆活化水的变种,RV-PAW,在rpoA和rpoD中发生突变；它显示出对橙汁中热量的耐受性增加，但最终不会构成重大威胁，因为它在制冷温度(8°C)下表现出健身成本，而其对秀丽隐杆线虫的毒力下降。耐热的变体，RV-HT,在flhC有突变,dnaJ：它在高生长温度（43°C）下表现出健身成本，并诱导秀丽隐杆线虫的形态功能改变。对香芹酚具有抗性的变体，RV-CAR,sseG有突变,flha,wbaV,这种变种不仅在实验室培养基和食物模型中表现出明显更高的耐热性，而且还有效地增加了其在冷藏温度下的生长适应性，同时保持了其毒力，秀丽隐杆线虫中Smurf表型的百分比最高。为了应对这些挑战，我们应用了一种将热处理与柠檬醛相结合的工艺，目的是利用橙汁热处理对房车造成的亚致死性损害。该方法实现了增强的微生物灭活,而不必提高热处理的强度。在RV-CAR的情况下，结果尤其令人鼓舞，最具挑战性的菌株，为此，我们通过多达3个log10失活周期提高了致死率。
