Mapping the risk factors, pathogens, and antibiotic of pharyngocutaneous fistula in patients after neck open surgery.

PURPOSE: Current literature lacks consensus on risk factors for pharyngocutaneous fistula (PCF), and empirical antibiotic guidelines for PCF are limited. The aim of this study was to reduce the incidence of PCF and improve antibiotic treatment efficacy for patients with PCF after open neck surgery by analyzing their clinical characteristics, pathogenic bacteria, and antibiotic susceptibility. METHODS: This study was a 13-year single-center retrospective cohort study, including 699 patients who underwent open neck surgery for laryngeal and hypopharyngeal cancer. Univariate and multivariate logistic regression analyses were conducted to identify the risk factors associated with the occurrence of PCF after surgery. The microbial species causing PCF were analyzed, and the antibiotic sensitivity of the top three pathogens was assessed. Venn diagrams were used to illustrate the antibiotics that exhibited 100% sensitivity against all three identified pathogens. RESULTS: The incidence of PCF after open neck surgery was 8%. Logistic univariate and multivariate analyses revealed that flap reconstruction (OR = 3.62, 95% CI [2.02-6.52]), history of preoperative radiotherapy (OR = 2.01, 95% CI [1.31-2.73]), significant postoperative bleeding (OR = 1.79, 95% CI [1.11-2.69]), and history of diabetes (OR = 1.34, 95% CI [1.29-2.46]) were significantly associated with PCF occurrence. Among the 38 cases of PCF patients, the top three identified pathogens were Pseudomonas aeruginosa, Escherichia coli, and Enterobacter cloacae. The antibiotics cefepime, meropenem, ticarcillin/clavulanic acid, and cefoperazone/sulbactam showed 100% sensitivity against these top three pathogens. CONCLUSION: Special attention should be given to patients undergoing open neck surgery, especially those with intraoperative flap reconstruction, a history of preoperative radiotherapy, postoperative bleeding, or diabetes. Strengthening monitoring and care is crucial in preventing the occurrence of PCF. According to antibiotic usage guidelines and considering the distribution of pathogens in PCF patients, empirical antibiotic treatment with cefoperazone/sulbactam or ticarcillin/clavulanic acid is recommended prior to obtaining susceptibility test results.

Structural insights into ribonucleoprotein dissociation by nucleocapsid protein interacting with non-structural protein 3 in SARS-CoV-2.

The coronavirus nucleocapsid (N) protein interacts with non-structural protein 3 (Nsp3) to facilitate viral RNA synthesis and stabilization. However, structural information on the N-Nsp3 complex is limited. Here, we report a 2.6 Å crystal structure of the N-terminal domain (NTD) of the N protein in complex with the ubiquitin-like domain 1 (Ubl1) of Nsp3 in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). One NTD and two Ubl1s formed a stable heterotrimer. We performed mutational analysis to reveal the key residues for this interaction. We confirmed the colocalization of SARS-CoV-2 N and Nsp3 in Huh-7 cells. N-Ubl1 interaction also exists in SARS-CoV and Middle East respiratory syndrome coronavirus. We found that SARS-CoV-2 Ubl1 competes with RNA to bind N protein in a dose-dependent manner. Based on our results, we propose a model for viral ribonucleoprotein dissociation through N protein binding to Ubl1 of Nsp3.

TP53 mutation-associated immune infiltration and a novel risk score model in HNSCC.

In HNSCC, few studies have focused on the relationship between wild-type TP53 and mutant TP53-related immunity and prognosis. Our objective was to explore how TP53 mutation regulates the immunophenotype of HNSCC and thus affects the prognosis of HNSCC. Cox and Lasso regression were used to establish a prognostic model of TP53-related immune genes, on which basis a nomogram was used to establish a clinical prediction model, and ROC curves were further used to evaluate the effectiveness of the model. The risk of death in the TP53WT group was only 0.68 times that in the TP53Mut group (HR = 0.68, CI: 0.5-0.91, P < 0.05). T cells, CD8 T cells, cytotoxic lymphocytes, B lineage, NK cells, myeloid dendritic cells, and fibroblasts were significantly different between the TP53Mut and TP53WT groups (all P < 0.05). Time - dependent ROC curves of nomogram were plotted for 1-, 3-, and 5-year survival to further verify the predictive power of the nomogram for prognosis, and the AUCs were 0.78, 0.82, and 0.83, respectively. We showed there are significant differences in the immune microenvironment associated with wild-type TP53 and mutant TP53. The immune model associated with TP53 mutation has a good prediction ability for the prognosis of HNSCC and may be of reference value for other tumors with high mutation rate of TP53. Notably, the effect of TP53 mutation on the prognosis of HNSCC could be illustrated from an immunologic perspective.

Microsporidia infection upregulates host energy metabolism but maintains ATP homeostasis.

Microsporidia are a group of obligate intracellular parasites which lack mitochondria and have highly reduced genomes. Therefore, they are unable to produce ATP via the tricarboxylic acid (TCA) cycle and oxidative phosphorylation. Instead, they have evolved strategies to obtain and manipulate host metabolism to acquire nutrients. However, little is known about how microsporidia modulate host energy metabolisms. Here, we present the first targeted metabolomics study to investigate changes in host energy metabolism as a result of infection by a microsporidian. Metabolites of silkworm embryo cell (BmE) were measured 48 h post infection by Nosema bombycis. Thirty metabolites were detected, nine of which were upregulated and mainly involved in glycolysis (glucose 6-phosphate, fructose 1,6-bisphosphate) and the TCA cycle (succinate, α-ketoglutarate, cis-aconitate, isocitrate, citrate, fumarate). Pathway enrichment analysis suggested that the upregulated metabolites could promote the synthesization of nucleotides, fatty acids, and amino acids by the host. ATP concentration in host cells, however, was not significantly changed by the infection. This ATP homeostasis was also found in Encephalitozoon hellem infected mouse macrophage RAW264.7, human monocytic leukemia THP-1, human embryonic kidney 293, and human foreskin fibroblast cells. These findings suggest that microsporidia have evolved strategies to maintain levels of ATP in the host while stimulating metabolic pathways to provide additional nutrients for the parasite.

The SARS-unique domain (SUD) of SARS-CoV and SARS-CoV-2 interacts with human Paip1 to enhance viral RNA translation.

The ongoing outbreak of severe acute respiratory syndrome (SARS) coronavirus 2 (SARS-CoV-2) demonstrates the continuous threat of emerging coronaviruses (CoVs) to public health. SARS-CoV-2 and SARS-CoV share an otherwise non-conserved part of non-structural protein 3 (Nsp3), therefore named as "SARS-unique domain" (SUD). We previously found a yeast-2-hybrid screen interaction of the SARS-CoV SUD with human poly(A)-binding protein (PABP)-interacting protein 1 (Paip1), a stimulator of protein translation. Here, we validate SARS-CoV SUD:Paip1 interaction by size-exclusion chromatography, split-yellow fluorescent protein, and co-immunoprecipitation assays, and confirm such interaction also between the corresponding domain of SARS-CoV-2 and Paip1. The three-dimensional structure of the N-terminal domain of SARS-CoV SUD ("macrodomain II", Mac2) in complex with the middle domain of Paip1, determined by X-ray crystallography and small-angle X-ray scattering, provides insights into the structural determinants of the complex formation. In cellulo, SUD enhances synthesis of viral but not host proteins via binding to Paip1 in pBAC-SARS-CoV replicon-transfected cells. We propose a possible mechanism for stimulation of viral translation by the SUD of SARS-CoV and SARS-CoV-2.

Innate and Adaptive Immune Responses Against Microsporidia Infection in Mammals.

Microsporidia are obligate intracellular and eukaryotic pathogens that can infect immunocompromised and immunocompetent mammals, including humans. Both innate and adaptive immune systems play important roles against microsporidian infection. The innate immune system can partially eliminate the infection by immune cells, such as gamma delta T cell, natural killer cells (NKs), macrophages and dendritic cells (DCs), and present the pathogens to lymphocytes. The innate immune cells can also prime and enhance the adaptive immune response via surface molecules and secreted cytokines. The adaptive immune system is critical to eliminate microsporidian infection by activating cytotoxic T lymphocyte (CTL) and humoral immune responses, and feedback regulation of the innate immune mechanism. In this review, we will discuss the cellular and molecular responses and functions of innate and adaptive immune systems against microsporidian infection.