肠道沙门氏菌是与低水分食品(LMFs)爆发相关的主要食源性病原体。然而,与沙门氏菌在LMF上的长期存活有关的基因仍然缺乏表征。在这项研究中,壳内开心果接种了基于Tn5的肠炎沙门氏菌P125109,鼠伤寒沙门氏菌14028s的突变文库,和S.NewportC4.2在大约108CFU/g和储存在25°C。然后使用转座子测序分析(Tn-seq)来确定接种后立即(T0)的每个Tn5插入位点的相对丰度。干燥后(T1),在120天(T120)。在肠炎沙门氏菌中,鼠伤寒杆菌,和S.Newport突变库,51、80和101个Tn5插入位点的相对丰度,分别,与T0相比,T1时显着较低,而在肠炎沙门氏菌和鼠伤寒沙门氏菌文库中,42和68Tn5插入位点的相对丰度,分别,在T120显著低于T1。在此竞争分析中相对丰度降低的Tn5插入位点位于DNA修复中,脂多糖生物合成和严格反应基因。选择在竞争测定中处于强阴性选择下的那些基因中的12个基因用于进一步研究。其中十个基因中的全基因缺失突变体,sspA,bara,uvrB,damx,rfbD,UvrY,lrhA,yife,rbsR,而ompR,在开心果上的个体生存受到损害。该发现强调了联合诱变和测序的价值,以鉴定对低水分食品中沙门氏菌存活重要的新基因。
Salmonella enterica is the leading foodborne pathogen associated with outbreaks involving low-moisture foods (LMFs). However, the genes involved in Salmonella\'s long-term survival on LMFs remain poorly characterized. In this study, in-shell pistachios were inoculated with Tn5-based mutant libraries of S. Enteritidis P125109, S. Typhimurium 14028s, and S. Newport C4.2 at approximate 108 CFU/g and stored at 25°C. Transposon sequencing analysis (Tn-seq) was then employed to determine the relative abundance of each Tn5 insertion site immediately after inoculation (T0), after drying (T1), and at 120 days (T120). In S. Enteritidis, S. Typhimurium, and S. Newport mutant libraries, the relative abundance of 51, 80, and 101 Tn5 insertion sites, respectively, was significantly lower at T1 compared to T0, while in libraries of S. Enteritidis and S. Typhimurium the relative abundance of 42 and 68 Tn5 insertion sites, respectively, was significantly lower at T120 compared to T1. Tn5 insertion sites with reduced relative abundance in this competition assay were localized in DNA repair, lipopolysaccharide biosynthesis and stringent response genes. Twelve genes among those under strong negative selection in the competition assay were selected for further study. Whole gene deletion mutants in ten of these genes, sspA, barA, uvrB, damX, rfbD, uvrY, lrhA, yifE, rbsR, and ompR, were impaired for individual survival on pistachios. The findings highlight the value of combined mutagenesis and sequencing to identify novel genes important for the survival of Salmonella in low-moisture foods.