Abstract：
Bacillary dysentery caused by Shigella spp. is a significant concern for human health. Small non-coding RNA (sRNA) plays a crucial role in regulating antibiotic resistance and virulence in Shigella spp. However, the specific mechanisms behind this phenomenon are still not fully understood. This study discovered two sRNAs (sRNA1039 and sRNA1600) that may be involved in bacterial resistance and virulence. By constructing deletion mutants (WT/ΔSR1039 and WT/ΔSR1600), this study found that the WT/ΔSR1039 mutants caused a two-fold increase in sensitivity to ampicillin, gentamicin and cefuroxime, and the WT/ΔSR1600 mutants caused a two-fold increase in sensitivity to cefuroxime. Furthermore, the WT/ΔSR1600 mutants caused a decrease in the adhesion and invasion of bacteria to HeLa cells (P<0.01), and changed the oxidative stress level of bacteria to reduce their survival rate (P<0.001). Subsequently, this study explored the molecular mechanisms by which sRNA1039 and sRNA1600 regulate antibiotic resistance and virulence. The deletion of sRNA1039 accelerated the degradation of target gene cfa mRNA and reduced its expression, thereby regulating the expression of pore protein gene ompD indirectly and negatively to increase bacterial sensitivity to ampicillin, gentamicin and cefuroxime. The inactivation of sRNA1600 reduced the formation of persister cells to reduce resistance to cefuroxime, and reduced the expression of type-III-secretion-system-related genes to reduce bacterial virulence by reducing the expression of target gene tomB. These results provide new insights into Hfq-sRNA-mRNA regulation of the resistance and virulence network of Shigella sonnei, which could potentially promote the development of more effective treatment strategies.
摘要：
由志贺氏菌引起的细菌性痢疾是人类健康的重要问题。小的非编码RNA(sRNA)在调节志贺氏菌的抗生素耐药性和毒力中起着至关重要的作用。然而,这种现象背后的具体机制仍然没有完全理解。我们的研究发现两种sRNAs（sRNA1039和sRNA1600）可能与细菌耐药性和毒力有关。通过构建缺失突变体（WT/ΔSR1039和WT/ΔSR1600），我们发现WT/ΔSR1039突变体对氨苄青霉素的敏感性增加了2倍，庆大霉素和头孢呋辛,WT/ΔSR1600突变体导致对头孢呋辛的敏感性增加2倍。此外，WT/ΔSR1600突变体导致细菌对HeLa细胞的粘附和侵袭能力下降(P<0.01),并改变细菌的氧化应激水平,降低其存活率(P<0.001)。随后，我们探讨了sRNA1039和sRNA1600调节抗生素耐药性和毒力的分子机制。sRNA1039的缺失加速了靶基因cfamRNA的降解并降低了其表达,从而间接和负调节孔蛋白基因ompD的表达，以增加细菌对氨苄青霉素的敏感性，庆大霉素和头孢呋辛。sRNA1600的失活通过降低靶基因tomB的表达，减少了对头孢呋辛的抗性，减少了III型分泌系统（T3SS）相关基因的表达，从而降低了细菌的毒力。这些为Hfq-sRNA-mRNA调控宋内志贺氏菌的抗性和毒力网络提供了新的见解，这可能会促进更有效的治疗策略的发展。
