Listeria monocytogenes sepsis in the nursing home community: a case report and short review of the literature

Biological Characteristics of Listeria monocytogenes Following Deletion of TatD-like Protein Gene

TatD is the subunit of the twin-arginine translocation (Tat) pathway. Members of TatD family are multifunctional, conserved and widely presented proteins in most prokaryotes. It has been reported that Tat can affect bacterial motility in some bacteria. This study was conducted to determine the contribution of the TatD protein (herein named LmTatD) to the regulation of flagella in Listeria monocytogenes. We constructed an LmTatD gene mutant in L. monocytogenes strain 10403 s and evaluated its biological characteristics. The results showed no difference in growth or morphology between the wild-type strain and the ΔLmTatD mutant. Intriguingly, the ΔLmTatD mutant showed impaired swimming motility and flagella structure but increased biofilm formation. Comparative proteomic analysis using tandem mass tag (TMT) combined with liquid chromatography-tandem mass spectrometry (LC‒MS/MS) was performed to determine differentially expressed proteins (DEPs). The results revealed that 134 proteins out of 2228 total proteins identified were differentially expressed, among which 18 proteins were upregulated and 116 proteins were downregulated in the ΔLmTatD mutant. Analysis of DEPs indicated that the reduced expression levels of the proteins related to flagellar assembly in the ΔLmTatD mutant correlate with its characteristics. Compared to the wild-type strain, the most downregulated proteins in the ΔLmTatD mutant included FlaA, FliD, FliR, FlgD, FlgL, and FlgG. Collectively, our data suggest that although LmTatD is not required for growth in L. monocytogenes, loss of LmTatD reduces flagellar production and motility by regulating flagellar assembly-related protein expression.

Retrospective Analysis of the Clinical Efficacy of Early Goal-Directed Therapy Combined with Meticulous Nursing Intervention in Patients with Posttraumatic Sepsis

Objective

To explore the intervention effect of early goal-directed therapy (EGDT) combined with meticulous nursing on patients with posttraumatic sepsis.

Methods

The data of 50 patients with posttraumatic sepsis undergoing EGDT in the emergency department of our hospital from January 2020 to December 2020 were retrospectively analyzed. According to different nursing methods, they were divided into control group (n = 25) with routine nursing measures and observation group (n = 25) with meticulous nursing measures. The application effect of the two nursing modes was scientifically evaluated.

Results

No statistical differences in general data were found between the two groups (P > 0.05). After 6 h of intervention, the circulatory function, oxygenation function, and renal function of both groups were better than those before intervention, and central venous pressure (CVP), mean arterial pressure (MAP), blood oxygen (PaO₂), oxygenation index (PaO₂/FiO₂), central venous oxygen saturation (ScvO₂), and urine volume in the observation group were notably higher than those in the control group (P < 0.05). The heart rate (HR), serum creatinine (SCr), and blood lactic acid in the observation group were notably lower than those in the control group (P < 0.05). The 28-day survival rate and quality of life after intervention in the observation group were notably higher than those in the control group, with obvious differences between the two groups (P < 0.05).

Conclusion

Meticulous nursing intervention for patients with posttraumatic sepsis undergoing EGDT can effectively improve the body's functional indexes, which is superior to the routine nursing in controlling the patients' condition, improving the survival rate and quality of life after intervention, and ensuring the clinical treatment effect. Therefore, it is worthy of promotion.

Multicombination Approach Suppresses Listeria monocytogenes-Induced Septicemia-Associated Acute Hepatic Failure: The Role of iRhom2 Signaling

The mortality rate of acute liver failure significantly increases due to fatal septicemia. Inactive rhomboid protein 2 (iRhom2) is an essential regulator of shedding TNF-α by trafficking with TNF-α converting enzyme (TACE). Fisetin, a flavonoid present in various fruits and plants, possesses anti-oxidative stress and anti-inflammatory activities. Here, multi-combination nanoparticles Fe@Au conjugated with fisetin, iRhom2 small interfering RNA (siRNA), and TNF-α inhibitor (FN) are prepared to examine their effects on fatal septicemia-associated hepatic failure induced by Listeria monocytogenes (LM) in mice and to reveal the underlying mechanisms. After LM infection, upregulation of glutamic-oxalacetic transaminease, glutamic-pyruvic transaminase, alkaline phosphatase, TNF-α, malondialdehyde, H₂ O₂ , and O₂^- is observedcompared to FN-treated mice. The iRhom2/TACE/TNF-α signals are enhanced in vivo and in vitro, resulting in oxidative stress, which is especially associated with the activation of kupffer cells and other macrophages. Decrease in Nrf2 activation and increase of inflammation-associated regulators are also noted in vivo and in vitro. Furthermore, overexpression of TNF-α derived from macrophages aggravates hepatic failure. Inversely, the processes above are restored by FN nanoparticles through the regulation of the iRhom2/TACE/TNF-α axis and Nrf2 activation. These findings suggest that FN may be a potential approach to protect against bacterial septicemia-related diseases by targeting iRhom2.