Prognostic value and potential mechanism of cellular senescence and tumor microenvironment in hepatocellular carcinoma: Insights from bulk transcriptomics and single-cell sequencing analysis.

The high mortality rate and postoperative recurrence of hepatocellular carcinoma (HCC) contribute to the burden on society and healthcare. The prognostic value and underlying mechanisms of cellular senescence and tumor microenvironment (TME) in HCC remain unclear. Bulk transcriptomic data were obtained from 368 HCC samples in The Cancer Genome Atlas-liver hepatocellular carcinoma cohort and 64 samples from the GSE116174 dataset. Single-cell RNA sequencing (scRNA-seq) data of HCC were obtained from the GSE149614 dataset, including 18 tumor samples from 10 patients. Prognosis-related cellular senescence genes and immune cells were identified through univariate analysis. Least absolute shrinkage and selection operator regression analysis was performed to construct the CellAge score and TME score, both of which were identified as independent prognostic factors for HCC based on multivariate Cox analysis. The combined CellAge and TME scores showed improved prognostic stratification for HCC patients, as confirmed by multivariate Cox analysis (p < .001). The gene set enrichment analysis (GSEA) revealed enrichment of the extracellular matrix receptor interaction signaling pathway in the group with high CellAge scores and low TME scores, which exhibited a worse prognosis. Single-cell sequencing results revealed higher expression activity of the cAMP response element modulator (CREM) extended transcription factor in HCC cells and most immune cells, indicating its involvement in TME remodeling. Finally, the tumor immune dysfunction and exclusion (TIDE) analysis demonstrated that the combined scores could predict the outcomes of immune therapy in patients with HCC. In conclusion, cellular senescence contributes to TME remodeling in HCC, and the developed CellAge and TME scores serve as independent prognostic factors and predictors of immune therapy in HCC.

"One-step" approach versus "Step-up" approach minimally invasive treatment for infected pancreatic necrosis: a study protocol for a single-center, prospective, randomized controlled trial.

BACKGROUND: Currently, the minimally invasive "Step-up" surgical strategy is still the main treatment for infected pancreatic necrosis (IPN). However, indiscriminate implementation of the "Step-up" strategy can lead to increased numbers of operations and prolonged hospital stay. The "Step-up" approach is not appropriate for some patients due to unavailabilty of a safe puncture path. Therefore, we developed the "One-step" surgical approach to treat IPN, which is safety. However, there is still a lack of comparison of the short and long-term efficacy between the "One-step" and "Step-up" approach. Consequently, we are conducting this clinical trial to provide a reference for IPN treatment. METHODS: This is an ongoing, single-center, randomized controlled trial of patients with IPN. The total sample size required for the trial (May 2021-December 2023) is approximately 128 patients. Patients will be randomly assigned to either an experimental group (One-step) or a control group (Step-up) at a ratio of 1:1 using the block randomization method. We used the case report forms and electronic data capture systems to obtain demographic information, preoperative laboratory examination, auxiliary examination results, surgery data, postoperative recovery outcomes, and follow-up outcomes. The patients will be followed up for 2 years after surgery. The primary endpoint is a composite endpoint, consisting of mortality and severe complications. The secondary endpoints include the incidence of organ dysfunction, the number of surgical procedures, mortality (the incidence of death in hospital and deaths within 30 days of discharge), hospital stay, intensive care unit stay, hospitalization costs, perioperative inflammatory marker changes, and short-and long-term complications. DISCUSSION: Compared with the "Step-up," the "One-step" minimally invasive surgery can significantly reduce the number of operations, reduce the length of hospital stay and hospitalization costs without increasing the incidence of composite endpoint events, and has better short- and long-term efficacy and safety. Additionally, there was no statistically significant difference in perioperative complications and mortality between "Step-up" and "One-step". This study will assist with the formulation of an effective and scientific "One-step" minimally invasive treatment strategy for IPN, and an understanding of this technique will facilitate clinical decision-making for IPN. Trial Registration ChiCTR2100044348. Trial status: Ongoing.

Unravelling the role of gut microbiota in acute pancreatitis: integrating Mendelian randomization with a nested case-control study.

Background: Gut microbiota may influence the development of acute pancreatitis (AP), a serious gastrointestinal disease with high morbidity and mortality. This study aimed to identify a causal link by investigating the relationship between gut microbiota and AP. Methods: Mendelian randomization (MR) and a nested case-control study were used to explore associations between gut microbiota composition and AP. 16S rRNA sequencing, random forest modelling (RF), support vector machine (SVM), and Kaplan-Meier survival analysis was applied to identify significant gut microbiota and their correlation with hospitalization duration in AP patients. Results: Bidirectional MR results confirmed a causal link between specific gut microbiota and AP (15 and 8 microbial taxa identified via forward and reverse MR, respectively). The 16S rRNA sequencing analysis demonstrated a pronounced difference in gut microbiota composition between cases and controls. Notably, after a comprehensive evaluation of the results of RF and SVM, Bacteroides plebeius (B. plebeius) was found to play a significant role in influencing the hospital status. Using a receiver operating characteristic (ROC) curve, the predictive power (0.757) of B. plebeius. Kaplan-Meier survival analysis offered further insight that patients with an elevated abundance of B. plebeius experienced prolonged hospital stays. Conclusion: Combining MR with nested case-control studies provided a detailed characterization of interactions between gut microbiota and AP. B. plebeius was identified as a significant contributor, suggesting its role as both a precursor and consequence of AP dynamics. The findings highlight the multifactorial nature of AP and its complex relationship with the gut microbiota. This study lays the groundwork for future therapeutic interventions targeting microbial dynamics in AP treatment.

Characteristics of small pancreatic neuroendocrine tumors and risk factors for invasion and metastasis.

Background: The number of people with small pancreatic neuroendocrine tumors (pNETs) (tumors with a diameter less than or equal to 2 cm) is gradually increasing, but the selection of treatment strategy is still controversial. Our aim was to characterize small pNETs with a poor prognosis and to define the impact of aggressive small pNETs on survival and the risk factors for the development of invasive disease. Methods: Patients with pNETs diagnosed between 2004 and 2019 and a tumor diameter of 2 cm or less were selected from the SEER Registry. Kaplan-Meier survival analysis was used to identify the factors affecting patient survival, and binary logistic regression was used to identify the associated risk factors. Results: A total of 3261 patients with pNETs were enrolled in the study. Both older and younger patients benefited from surgery. Regional invasion occurred in 10% of the patients, and distant metastases occurred in 9% of the patients, but in both categories, those who underwent surgery had better survival outcomes than those who did not. There was no difference in survival between patients with a tumor diameter of 1-2 cm and those with a tumor diameter of less than 1 cm, and there was no difference in survival between patients with functional and nonfunctional small pNETs. However, the survival of patients with pNETs in the head of the pancreas was worse than that of patients with tumors in other parts of the pancreas. Survival was worse in elderly patients and in those with poorly differentiated and undifferentiated tumors. Lymphatic metastasis, regional invasion, and distant metastasis all worsened the prognosis of patients. The presence or absence of neuroendocrine function, the degree of tumor differentiation, and the location of the tumor were associated with the risk of lymphatic metastasis and regional invasion; the risk factors for distant metastasis were associated with the degree of differentiation and tumor location. Conclusion: The pNETs ≤ 2 cm in diameter could be still aggressive, and patient prognosis worsens after invasive disease develops. Attention to the characteristics of aggressive tumors can improve patient survival.

Characteristics and Incidence of Colon Complication in Necrotizing pancreatitis: A Propensity Score-Matched Study.

Objective: To clarify the incidence of colonic complications in patients with NP and their impact on prognosis. Methods: The clinical data of NP patients admitted to the Department of General Surgery of Xuanwu Hospital, Capital Medical University from January 2014 to December 2020 were retrospectively analyzed. Patients were grouped according to the presence or absence of colonic complications, and the clinical prognosis of the two groups was analyzed after matching using a 1:1 propensity score, The primary study endpoint was patient mortality during hospitalization. Data are reported as median (range) or percentage of patients (%). Results: A total of 306 patients with NP were included in this study, and the incidence of colonic complications was 12.4%, including 15 cases of colonic obstruction, 17 cases of colonic fistula, and 9 cases of colonic hemorrhage. Before matching, patients in the colonic group had severe admissions and poor clinical outcomes (P<0.05). After matching, the baseline data and clinical characteristics at admission were comparable between the two groups of patients. In terms of clinical outcomes, although the mortality was similar in the two groups (P>0.05), but patients in the colonic group were more likely to have multiorgan failure, length of nutrition support, number of minimally invasive interventions, number of extra-pancreatic infections, length of ICU stay and total length of stay were significantly higher than those of patients in the group without colonic complications (P<0.05). During long-term follow-up, patients in the colonic group were more likely to develop recurrent pancreatitis. Conclusion: About 12.4% of NP patients developed colonic complications, and after PSM it was found that colonic complications only led to a longer hospital stay and an increased number of clinical interventions in NP patients and did not increase the mortality.

Identification of key microRNAs in exosomes derived from patients with the severe acute pancreatitis.

OBJECTIVE: Exosomes have been identified as important carriers of various genetic materials, including microRNAs (miRNAs). Increasing evidence indicates that the course of severe acute pancreatitis (SAP) is associated with miRNAs transported by exosomes. We aimed to identify the signature miRNAs as biomarkers of SAP. METHODS: We obtained exosomes from the SAP patients' blood. After separation, purification, and identification, we performed high-throughput sequencing and screened the differentially expressed(DE) miRNAs in the exosomes. Bioinformatics analysis was performed to identified the target genes of the miRNAs and the pathways enriched based on Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses, and selected the key miRNAs related to SAP. Total RNA was extracted from patient serum exosomes to detect the expression levels of the selected miRNAs in exosomes of three experimental groups (mild -, moderately severe -, and severe AP) and a control group, using Real-time quantitative polymerase chain reaction (RT-qPCR). RESULTS: 272 DE miRNAs were identified between SAP and control group. Using bioinformatics analysis, we determined that the functions of the target genes were enriched in six signaling pathways including focal adhesion. Based on this, seven candidate signature miRNAs were selected: miR-603, miR-548ad-5p, miR-122-5p, miR-4477a, miR-192-5p, miR-215-5p, and miR-583. The RT-qPCR results of the seven miRNAs in the SAP group were consistent with the sequencing results. CONCLUSION: Exosome-derived miR-603, miR-548ad-5p, miR-122-5p, miR-4477a, miR-192-5p, miR-215-5p, miR-583 are positively correlated with SAP, which might provide new insights into the pathogenesis of SAP and serve as the biomarkers of SAP.

Acinous cell AR42J-derived exosome miR125b-5p promotes acute pancreatitis exacerbation by inhibiting M2 macrophage polarization via PI3K/AKT signaling pathway.

BACKGROUND: The incidence rate of acute pancreatitis (AP), which is a pathophysiological process with complex etiology, is increasing globally. miR-125b-5p, a bidirectional regulatory miRNA, is speculated to exhibit anti-tumor activity. However, exosome-derived miR-125b-5p in AP has not been reported. AIM: To elucidate the molecular mechanism of exosome-derived miR-125b-5p promoting AP exacerbation from the perspective of the interaction between immune cells and acinar cells. METHODS: Exosomes derived from AR42J cells were isolated and extracted in active and inactive states by an exosome extraction kit, and were verified via transmission electron microscopy, nanoparticle tracking analysis, and western blotting. RNA sequencing assay technology was used to screen differentially expressed miRNAs in active and inactive AR42J cell lines, and bioinformatics analysis was used to predict downstream target genes of miR-125b-5p. The expression level of miR-125b-5p and insulin-like growth factor 2 (IGF2) in the activated AR42J cell line and AP pancreatic tissue were detected by quantitative real-time polymerase chain reaction and western blots. The changes in the pancreatic inflammatory response in a rat AP model were detected by histopathological methods. Western Blot was used to detect the expression of IGF2, PI3K/AKT signaling pathway proteins, and apoptosis and necrosis related proteins. RESULTS: miR-125b-5p expression was upregulated in the activated AR42J cell line and AP pancreatic tissue, while that of IGF2 was downregulated. In vitro experiments confirmed that miR-125b-5p could promote the death of activated AR42J cells by inducing cell cycle arrest and apoptosis. In addition, miR-125b-5p was found to act on macrophages to promote M1 type polarization and inhibit M2 type polarization, resulting in a massive release of inflammatory factors and reactive oxygen species accumulation. Further research found that miR-125b-5p could inhibit the expression of IGF2 in the PI3K/AKT signaling pathway. Additionally, in vivo experiments revealed that miR-125b-5p can promote the progression of AP in a rat model. CONCLUSION: miR-125b-5p acts on IGF2 in the PI3K/AKT signaling pathway and promotes M1 type polarization and inhibits M2 type polarization of macrophage by inhibiting IGF2 expression, resulting in a large release of pro-inflammatory factors and an inflammatory cascade amplification effect, thus aggravating AP.

Role of m6A writers, erasers and readers in cancer.

The N(6)-methyladenosine (m6A) modification is the most pervasive modification of human RNAs. In recent years, an increasing number of studies have suggested that m6A likely plays important roles in cancers. Many studies have demonstrated that m6A is involved in the biological functions of cancer cells, such as proliferation, invasion, metastasis, and drug resistance. In addition, m6A is closely related to the prognosis of cancer patients. In this review, we highlight recent advances in understanding the function of m6A in various cancers. We emphasize the importance of m6A to cancer progression and look forward to describe future research directions.

Prognostic biomarkers of pancreatic cancer identified based on a competing endogenous RNA regulatory network.

Background: Pancreatic cancer is an insidious and heterogeneous malignancy with poor prognosis that is often locally unresectable. Therefore, determining the underlying mechanisms and effective prognostic indicators of pancreatic cancer may help optimize clinical management. This study was conducted to develop a prognostic model for pancreatic cancer based on a competing endogenous RNA (ceRNA) network. Methods: We obtained transcriptomic data and corresponding clinicopathological information of pancreatic cancer samples from The Cancer Genome Atlas (TCGA) database (training set). Based on the ceRNA interaction network, we screened candidate genes to build prediction models. Univariate Cox regression analysis was performed to screen for genes associated with prognosis, and least absolute shrinkage and selection operator (LASSO) regression analysis was conducted to construct a predictive model. A receiver operating characteristic (ROC) curve was drawn, and the C-index was calculated to evaluate the accuracy of the prediction model. Furthermore, we downloaded transcriptomic data and related clinical information of pancreatic cancer samples from the Gene Expression Omnibus database (validation set) to evaluate the robustness of our prediction model. Results: Eight genes (ANLN, FHDC1, LY6D, SMAD6, ACKR4, RAB27B, AUNIP, and GPRIN3) were used to construct the prediction model, which was confirmed as an independent predictor for evaluating the prognosis of patients with pancreatic cancer through univariate and multivariate Cox regression analysis. By plotting the decision curve, we found that the risk score model is an independent predictor has the greatest impact on survival compared to pathological stage and targeted molecular therapy. Conclusions: An eight-gene prediction model was constructed for effectively and independently predicting the prognosis of patients with pancreatic cancer. These eight genes identified show potential as diagnostic and therapeutic targets.

Risk Factors and Outcomes of Multidrug-Resistant Bacteria Infection in Infected Pancreatic Necrosis Patients.

Objective: The incidence of acute pancreatitis (AP) is increasing. Twenty percent of AP patients with developing necrotizing pancreatitis (NP), while ~40-70% of NP patients develop potentially fatal infectious complications. When patients are suspected or confirmed infected pancreatic necrosis (IPN), antibiotics should be administered timeously to control the infection, but long-term use of antibiotics can lead to multidrug-resistant bacteria (MDRB) infection and eventually to increased mortality. Our study aimed to determine the incidence of MDRB infection and evaluate the risk factors for MDRB infection in IPN patients. Methods: Clinical data of IPN patients admitted to the general surgery department of Xuanwu Hospital of Capital Medical University between January 1, 2014, and December 31, 2021, were retrospectively analyzed. Results: IPN patients (n = 267) were assigned to MDRB infection (n = 124) and non-MDRB infection (n = 143) groups. On admission, patients in the MDRB group had a higher modified computer tomography severity index (CTSI) score (P < 0.05), pancreatic necrosis degree, and PCT level (P < 0.05) than those in the non-MDRB group, and the prognosis of patients in MDRB group was poor. The most common gram-negative bacteria were Acinetobacter baumannii (n = 117), the most common gram-positive bacteria were Enterococcus faecium (n = 98), and the most common fungal infection was Candida albicans (n = 47). Multivariable analysis showed that complications of EPI (OR: 4.116, 95% CI: 1.381-12.271, P = 0.011), procalcitonin (PCT) level at admission (OR: 2.728, 95% CI: 1.502-4.954, P = 0.001), and degree of pancreatic necrosis (OR: 2.741, 95% CI: 1.109-6.775, P = 0.029) were independent risk factors for MDRB infection in IPN patients. Conclusion: We identified common infectious strains and risk factors for MDRB infection in IPN patients.

How to Identify the Indications for Early Intervention in Acute Necrotizing Pancreatitis Patients: A Long-Term Follow-Up Study.

Aim: To explore the indications for early intervention in patients with acute necrotizing pancreatitis (ANP) and evaluate the effect of early intervention on the prognosis of ANP patients. Methods: The clinical data of patients with ANP who underwent general surgery at Xuanwu Hospital of Capital Medical University from January 1, 2014, to December 31, 2020, were collected retrospectively. The patients were followed-up every 6 months after discharge, and the last follow-up date was June 30, 2021. Results: A total of 98 patients with ANP were included in the study. They were divided into an early group (n= 43) and a delayed group (n = 55) according to the first percutaneous drainage (PCD) intervention time (≤ 4 weeks or > 4 weeks). Body temperature, inflammatory factor levels, and the number of patients with persistent organ failure (POF) were higher in the early group than in the delayed group. After the minimally invasive intervention, the body temperature and inflammatory factors of the two groups decreased significantly, most patients with POF improved, and the number of patients with reversal of POF in the early group was higher than that in the delayed group. Although the patients in the early group required more surgical intervention than those in the delayed group, there was no significant difference in mortality, incidence of postoperative complications, total length of hospital stay, or operation cost between the two groups. During long-term follow-up, there was no significant difference in the incidence of short-term and long-term complications and overall survival between the two groups. Conclusions: Compared to patients in the delayed group, early intervention did not affect the prognosis of patients with ANP. It may be more suitable for patients with ANP with deterioration [such as POF or infected pancreatic necrosis (IPN)].

KLF16 promotes pancreatic adenocarcinoma cell proliferation and migration by positively regulating SMAD6.

BACKGROUND: Pancreatic adenocarcinoma (PAAD) is a cancerous tumor with an extremely poor 5-year survival rate. The exploration of biomarkers for the diagnosis and treatment of PAAD is crucial in clinical practice. Krüppel-like factors (KLFs) are involved in a variety of biological functions in cells. According to multiple studies, KLF16 behave as an oncogene in prostate, breast and gastric cancers. However, no research has been done on the significance of KLF16 in PAAD. AIM: To explore the molecular mechanisms of KLF16 in PAAD. METHODS: KLF16 was identified in the tumor specimens and normal tissues by GEPIA database and verified by quantitative real-time PCR (qRT-PCR). Knockdown or exogenous expression of KLF16, combined with in vitro and in vivo assays, was performed to show the functional significance of KLF16. The molecular mechanism of KLF16 was demonstrated by qRT-PCR, western blotting, immunoprecipitation assay and flow cytometry. RESULTS: We showed that KLF16 was highly expressed in PAAD patients based on the GEPIA database. KLF16 silencing suppressed while KLF16 overexpression promoted the malignant function of PAAD cells. Based on RNA sequencing, we discovered that KLF16 potentiated the expression of SMAD6 in PAAD cells. SMAD6 transcript abundance was increased and positively correlated with KLF16 expression in PAAD samples. In addition, inhibiting SMAD6 was able to mitigate the effects of KLF16 overexpression on PAAD cell processes, suggesting the importance of SMAD6 in the development of KLF16-triggered PAAD. CONCLUSION: KLF16/SMAD6 axis might be explored as a therapeutic target for PAAD therapy.

Acinar Cells Derived Exosomes Alleviate the Severity of Acute Pancreatitis.

BACKGROUND: Acute pancreatitis (AP) is a serious and can be lethal disease, with an incidence of 13 to 45 per 100,000 individuals per year. The underlying mechanism of AP is not fully understood. Exosomes have recently been identified as intercellular messengers that can participate in the pathogenesis of various diseases. Exosomes secreted by noninflammatory acinar cells may affect the activated and injured acinar cells during AP. AIM: To investigate the effect of exosomes derived from acinar cells on the pathogenesis of AP. METHODS: Nanoparticle tracking analysis was applied to evaluating the exosomes derived from AR42J acinar cells. The viability and apoptosis of AP in vitro model cells were evaluated. Wistar rats were used to establish the in vivo AP rat model and the levels of serum pro-inflammatory cytokines and morphological changes in the pancreatic tissues were assessed. RNA sequencing and Kyoto Encyclopedia of Genes and Genomes databases (KEGG) based RNA enrichment analyses were applied to exploring the mechanisms underlying the effect of exosomes on the pathogenesis of AP. RESULTS: Acinar cell exosomes reduced the level of intracellular ROS production and improved the viability of AP model acinar cells by inhibiting apoptosis during AP. The exosomes decreased the circulating levels of IL-6 and TNF-alpha, and reduced the pathological scores and wet/dry weight ratios of pancreatic tissue in AP in vivo model rats. Among the upregulated and downregulated RNAs analyzed, the MAPK and NF-kappaB signaling pathways might be involved in the mechanisms underlying the protective effects of acinar cell-derived exosomes in AP. CONCLUSION: Acinar cell-derived exosomes could reduce the apoptosis and ROS production in acinar cells during AP, and may alleviate the severity of AP via the MAPK and NF-kappaB signaling pathways.

Comparison of safety, efficacy, and long-term follow-up between "one-step" and "step-up" approaches for infected pancreatic necrosis.

BACKGROUND: Although the "Step-up" strategy is the primary surgical treatment for infected pancreatic necrosis, it is not suitable for all such patients. The "One-step" strategy represents a novel treatment, but the safety, efficacy, and long-term follow-up have not yet been compared between these two approaches. AIM: To compare the safety, efficacy, and long-term follow-up of two surgical approaches to provide a reference for infected pancreatic necrosis treatment. METHODS: This was a retrospective analysis of infectious pancreatic necrosis patients who underwent "One-step" or "Step-up" necrosectomy at Xuan Wu Hospital, Capital Medical University, from May 2014 to December 2020. The primary outcome was the composite endpoint of severe complications or death. Patients were followed up every 6 mo after discharge until death or June 30, 2021. Statistical analysis was performed using SPSS 21.0 and GraphPad Prism 8.0, and statistical significance was set at P < 0.05. RESULTS: One-hundred-and-fifty-eight patients were enrolled, of whom 61 patients underwent "One-step" necrosectomy and 97 patients underwent "Step-up" necrosectomy. During the long-term follow-up period, 40 patients in the "One-step" group and 63 patients in the "Step-up" group survived. The time from disease onset to hospital admission (53.69 ± 38.14 vs 32.20 ± 20.75, P < 0.001) and to initial surgical treatment was longer in the "Step-up" than in the "One-step" group (54.38 ± 10.46 vs 76.58 ± 17.03, P < 0.001). Patients who underwent "Step-up" necrosectomy had a longer hospitalization duration (65.41 ± 28.14 vs 52.76 ± 24.71, P = 0.02), and more interventions (4.26 ± 1.71 vs 3.18 ± 1.39, P < 0.001). Postoperative inflammatory indicator levels were significantly lower than preoperative levels in each group. Although the incisional hernia incidence was higher in the "One-step" group, no significant difference was found in the composite outcomes of severe complications or death, new-onset organ failure, postoperative complications, inflammatory indicators, long-term complications, quality of life, and medical costs between the groups (P > 0.05). CONCLUSION: Compared with the "Step-up" approach, the "One-step" approach is a safe and effective treatment method with better long-term quality of life and prognosis. It also provides an alternative surgical treatment strategy for patients with infected pancreatic necrosis.

Timing, distribution, and microbiology of infectious complications after necrotizing pancreatitis.

BACKGROUND: Acute pancreatitis (AP) is a common acute abdominal disease worldwide, and its incidence rate has increased annually. Approximately 20% of AP patients develop into necrotizing pancreatitis (NP), and 40% to 70% of NP patients have infectious complications, which usually indicate a worse prognosis. Infection is an important sign of complications in NP patients. AIM: To investigate the difference in infection time, infection site, and infectious strain in NP patients with infectious complications. METHODS: The clinical data of AP patients visiting the Department of General Surgery of Xuanwu Hospital of Capital Medical University from January 1, 2014 to December 31, 2018 were collected retrospectively. Enhanced computerized tomography or magnetic resonance imaging findings in patients with NP were included in the study. Statistical analysis of infectious bacteria, infection site, and infection time in NP patients with infectious complications was performed, because knowledge about pathogens and their antibiotic susceptibility patterns is essential for selecting an appropriate antibiotic. In addition, the factors that might influence the prognosis of patients were analyzed. RESULTS: In this study, 539 strains of pathogenic bacteria were isolated from 162 patients with NP infection, including 212 strains from pancreatic infections and 327 strains from extrapancreatic infections. Gram-negative bacteria were the main infectious species, the most common of which were Escherichia coli and Pseudomonas aeruginosa. The extrapancreatic infection time (9.1 ± 8.8 d) was earlier than the pancreatic infection time (13.9 ± 12.3 d). Among NP patients with early extrapancreatic infection (< 14 d), bacteremia (25.12%) and respiratory tract infection (21.26%) were predominant. Among NP patients with late extrapancreatic infection (> 14 d), bacteremia (15.94%), respiratory tract infection (7.74%), and urinary tract infection (7.71%) were predominant. Drug sensitivity analysis showed that P. aeruginosa was sensitive to enzymatic penicillins, third- and fourth-generation cephalosporins, and carbapenems. Acinetobacter baumannii and Klebsiella pneumoniae were sensitive only to tigecycline; Staphylococcus epidermidis and Enterococcus faecium were highly sensitive to linezolid, tigecycline, and vancomycin. CONCLUSION: In this study, we identified the timing, the common species, and site of infection in patients with NP.