Salmonella Enteritidis has caused, since the 1980s, a sustained epidemic of human infections in many countries. This study analyzed S. Enteritidis strains isolated before and after the epidemic period in Brazil regarding their capacities to survive to acid, oxidative, and high-temperature stresses, and capacity to grow in egg albumen. Moreover, the ability to invade human epithelial cells (Caco-2) and to survive inside human (U937) and chicken (HD11) macrophages was checked. Post-epidemic strains showed a better ability to survive after 10 min under acid stress at 37 °C (P ≤ 0.05). However, both groups of strains showed similar ability to survive after 1 h under acid stress at 37 °C and at 42 °C independently of the time of exposure. Similar ability was verified in both groups of strains regarding oxidative stress, growth in egg albumen, high-temperature stress, invasion to Caco-2 cells, and invasion and survival in macrophages. In conclusion, post-epidemic S. Enteritidis strains showed a better ability to survive under the acid stress found in the stomach, which might be an advantage to reach the intestine and colonize chickens and humans. However, both groups of strains did not differ significantly in the majority of the phenotypic tests analyzed in this study.

中文翻译：

---

巴西流行前后分离的肠炎沙门氏菌血清型肠炎沙门菌的表型分析

自 1980 年代以来，肠炎沙门氏菌在许多国家引起了人类感染的持续流行。本研究分析了巴西流行期前后分离的肠炎沙门氏菌菌株，分析了它们在酸、氧化和高温胁迫下存活的能力，以及在蛋清中生长的能力。此外，还检查了侵入人类上皮细胞 (Caco-2) 和在人类 (U937) 和鸡 (HD11) 巨噬细胞内存活的能力。疫后菌株在 37°C 的酸胁迫下 10 分钟后显示出更好的存活能力（P ≤ 0.05）。然而，两组菌株在 37°C 和 42°C 的酸胁迫下 1 小时后显示出相似的存活能力，与暴露时间无关。两组菌株在氧化应激、卵蛋白生长、高温胁迫、对 Caco-2 细胞的侵袭以及巨噬细胞的侵袭和存活。总之，流行后的肠炎沙门氏菌菌株在胃中发现的酸应激下表现出更好的生存能力，这可能是到达肠道并定植鸡和人类的优势。然而，在本研究中分析的大多数表型测试中，两组菌株没有显着差异。