The hemostatic activity and Mechanistic roles of glucosyloxybenzyl 2-isobutylmalate extract (BSCE) from Bletilla striata (Thunb.) Rchb.f. in Inhibiting pulmonary hemorrhage.

Background: Hemorrhagic events cause numerous deaths annually worldwide, highlighting the urgent need for effective hemostatic drugs. The glucosyloxybenzyl 2-isobutylmalates Control Extract (BSCE) from the orchid plant Bletilla striata (Thunb.) Rchb.f. has demonstrated significant hemostatic activity in both in vitro and in vivo studies. However, the effect and mechanism of BSCE on non-traumatic bleeding remain unclear. Methods: Pulmonary hemorrhage was induced in 40 Sprague-Dawley rats by administering Zingiber officinale Roscoe. for 14 days. These rats were then randomly divided into five groups: model (Mod), positive control (YNBY), and BSCE low, medium, and high-dose groups. An additional 8 rats served as the control group (Con). The BSCE groups received different doses of BSCE for 10 days, while the YNBY group received Yunnan Baiyao suspension. The effects on body weight, food and water intake, red blood cell count (RBC), hemoglobin concentration (HGB), lung tissue pathology, platelet count, coagulation parameters, and fibrinolytic system markers were evaluated. Network pharmacology and molecular docking analyses were also conducted to identify potential targets and pathways involved in BSCE's effects. Results: BSCE treatment significantly improved body weight, food intake, and water consumption in rats with pulmonary hemorrhage. RBC and HGB levels increased significantly in the BSCE medium and high-dose groups compared to the Mod group (P < 0.05). Pathological examination revealed that BSCE reduced lung tissue hemorrhage and inflammation, with improvements in alveolar structure. BSCE also positively affected platelet count, thrombin time (TT), activated partial thromboplastin time (APTT), fibrinogen (FIB) levels, and fibrinolytic markers (D-dimer, PAI-1, and t-PA). Network pharmacology and molecular docking identified key targets such as MMPs, CASPs, and pathways including IL-17 and TNF signaling, suggesting BSCE's involvement in hemostasis and anti-inflammatory processes. Conclusions: BSCE exhibits significant hemostatic and protective effects on Z.officinale-induced pulmonary hemorrhage in rats by improving hematological parameters, reducing lung tissue damage, and modulating the coagulation and fibrinolytic systems. The study provides evidence supporting the potential of BSCE as a therapeutic agent for hemorrhagic diseases, with its efficacy linked to multi-target and multi-pathway interactions.

Asymmetric one-carbon ring expansion of diverse N-heterocycles via copper-catalyzed diyne cyclization.

One-carbon ring expansion reaction of N-heterocycles has gained particular attention in the past decade because this method allows for the conversion of readily available N-heterocycles into potentially useful complex ring-expanded N-heterocycles, which are inaccessible by traditional methods. However, the catalytic asymmetric variant of this reaction has been rarely reported to date. Herein, we disclose an enantioselective one-carbon ring expansion reaction through chiral copper-catalyzed diyne cyclization, leading to the practical, atom-economic and divergent assembly of an array of valuable chiral N-heterocycles bearing a quaternary stereocenter in generally good to excellent yields with excellent enantioselectivities (up to >99% ee). This protocol represents the first example of asymmetric one-carbon ring expansion reaction of N-heterocycles based on alkynes.

Gut microbiome and metabolites mediate the benefits of caloric restriction in mice after acute kidney injury.

The role of gut microbiome in acute kidney injury (AKI) is increasing recognized. Caloric restriction (CR) has been shown to enhance the resistance to ischemia/reperfusion injury to the kidneys in rodents. Nonetheless, it is unknown whether intestinal microbiota mediated CR protection against ischemic/reperfusion-induced injury (IRI) in the kidneys. Herein, we showed that CR ameliorated IRI-elicited renal dysfunction, oxidative stress, apoptosis, and inflammation, along with enhanced intestinal barrier function. In addition, gut microbiota depletion blocked the favorable effects of CR in AKI mice. 16S rRNA and metabolomics analysis showed that CR enriched the gut commensal Parabacteroides goldsteinii (P. goldsteinii) and upregulated the level of serum metabolite dodecafluorpentan. Intestinal colonization of P. goldsteinii and oral administration of dodecafluorpentan showed the similar beneficial effects as CR in AKI mice. RNA sequencing and experimental data revealed that dodecafluorpentan protected against AKI-induced renal injury by antagonizing oxidative burst and NFκB-induced NLRP3 inflammasome activation. In addition, we screened and found that Hamaudol improved renal insufficiency by boosting the growth of P. goldsteinii. Our results shed light on the role of intestinal microbiota P. goldsteinii and serum metabolites dodecafluorpentan in CR benefits to AKI.

DCAF13 promotes ovarian cancer progression by activating FRAS1-mediated FAK signaling pathway.

Cullin-RING ubiquitin ligase 4 (CRL4) is closely correlated with the incidence and progression of ovarian cancer. DDB1- and CUL4-associated factor 13 (DCAF13), a substrate-recognition protein in the CRL4 E3 ubiquitin ligase complex, is involved in the occurrence and development of ovarian cancer. However, its precise function and the underlying molecular mechanism in this disease remain unclear. In this study, we confirmed that DCAF13 is highly expressed in human ovarian cancer and its expression is negatively correlated with the overall survival rate of patients with ovarian cancer. We then used CRISPR/Cas9 to knockout DCAF13 and found that its deletion significantly inhibited the proliferation, colony formation, and migration of human ovarian cancer cells. In addition, DCAF13 deficiency inhibited tumor proliferation in nude mice. Mechanistically, CRL4-DCAF13 targeted Fraser extracellular matrix complex subunit 1 (FRAS1) for polyubiquitination and proteasomal degradation. FRAS1 influenced the proliferation and migration of ovarian cancer cell through induction of the focal adhesion kinase (FAK) signaling pathway. These findings collectively show that DCAF13 is an important oncogene that promotes tumorigenesis in ovarian cancer cells by mediating FRAS1/FAK signaling. Our findings provide a foundation for the development of targeted therapeutics for ovarian cancer.

Endonuclease G is dispensable for sperm mitochondrial DNA elimination during spermatogenesis in mice.

Maternal inheritance of mitochondrial DNA (mtDNA) is a widespread phenomenon in eukaryotes. Our earlier research indicated that sperm mtDNA is removed prior to fertilization in mice, and Endonuclease G (ENDOG) orchestrates the degradation of sperm mitochondria in Caenorhabditis elegans. However, the mechanisms underlying sperm mtDNA disposal in mammals remain poorly understood. To investigate the potential role of ENDOG in sperm mtDNA elimination, we created Endog knockout (Endog-/-) mice. Our findings revealed that Endog-/- mice maintained normal spermatogenesis and fertility. Most strikingly, we detected no substantial discrepancy in sperm mtDNA copy number between Endog-/- and control mice. Furthermore, we noted that sperm mtDNA copy numbers were unchanged in both less motile and motile sperm isolated by Percoll gradient centrifugation from Endog-/- and control mice. Taken together, our results indicate that ENDOG is not essential for spermatogenesis or the elimination of sperm mtDNA in mice.

Flavopiridol inhibits oocyte maturation, reduces oocyte quality and blocks cumulus cell function.

Flavopiridol (FP) is a plant-derived flavonoidis and used to treat cancers, fungal infections and inflammation-related diseases. However, it is not clear whether it has side effects on the female reproductive system. In this study, we aimed to investigate the toxic effects and potential underlying mechanisms of FP on oocyte maturation and cumulus cell expansion in mice. Cumulus-oocyte complexes (COCs) were cultured in vitro with FP of gradient concentration (50-1000nM), according to the plasma concentration of FP in the clinical trial. The maturation rate and cumulus expansion index of oocytes were counted and studied by immunofluorescence staining, qRT-PCR, oocyte chromosome preparation and so on. The results showed that the FP-exposed COCs inhibited the oocyte maturation and cumulus cell expansion, leading to cell apoptosis in a dose dependent way. Oocytes exposed to 500nM FP showed abnormalities in the spindle structure and chromosome arrangement, ultimately leading to the oocyte maturation arrest and aneuploidy. This may be due to the excessive oxidative stress caused by mitochondrial membrane potential damage and mislocalization. Therefore, when FP is used for cancer treatment, its side effects on the female reproductive system should be seriously considered.

CtIP regulates G2/M transition and bipolar spindle assembly during mouse oocyte meiosis.

CtBP-interacting protein (CtIP) is known for its multifaceted roles in DNA repair and genomic stability, directing the homologous recombination-mediated DNA double-stranded break (DSBs) repair pathway via DNA end resection, an essential error-free repair process vital for genome stability. Mammalian oocytes are highly prone to DNA damage accumulation due to prolonged G2/prophase arrest. Here, we explore the functions of CtIP in meiotic cell cycle regulation via a mouse oocyte model. Depletion of CtIP by siRNA injection results in delayed germinal vesicle breakdown and failed polar body extrusion. Mechanistically, CtIP deficiency increases DNA damage and decreases the expression and nuclear entry of CCNB1, resulting in marked impairment of meiotic resumption, which can be rescued by exogenous CCNB1 overexpression. Furthermore, depletion of CtIP disrupts MTOCs coalescence at spindle poles as indicated by failed accumulation of γ-tubulin, p-Aurora kinase A, Kif2A, and TPX2, leading to abnormal spindle assembly and prometaphase arrest. These results provide valuable insights into the important roles of CtIP in the G2/M checkpoint and spindle assembly in mouse oocyte meiotic cell cycle regulation.

Analysis on the epidemiological and drug resistance characteristics of osteoarticular tuberculosis in South-central China.

Objective: Osteoarticular tuberculosis (OATB) is one of the most common forms of extrapulmonary tuberculosis; however, limited epidemiological data are available on this public health concern worldwide, especially in developing countries. This study aimed to analyze the clinical epidemiology and drug resistance characteristics of OATB cases in Hunan province which located in South-central China. Methods: We retrospectively enrolled OATB patients with Mycobacterium tuberculosis culture positive at Hunan Chest Hospital from January 2013 through March 31, 2022. The multiple demographic, clinical variables and drug susceptibility data of the patients were collected from the hospital's electronic patient records. Descriptive statistical methods, Chi-square test and logistic regression analysis were employed as statistical methods. Results: Of the 269 OATB cases, 197 (73.23%) were males, 206 (76.85%) were farmers; patients' ages ranged from 5 to 85 years, 57 (21.19%) aged at 20-29 years old and 52 (19.33%) aged at 60-69 years old. In terms of the disease, 177 (65.80%) had spinal TB with most occurrence in lumbar vertebrae (26.02%, 70/269), multiple spinal sites (18.96%, 51/269) and thoracic vertebrae (15.24%, 41/269). Outside of the spine, OATB mainly occurred in the lower limb (13.38%, 36/269). In terms of drug resistance, 40 (14.87%) and 72 (26.77%) were resistant to rifampicin (RFP) and isoniazid (INH) respectively; 38 (14.13%) were multi-drug resistant (MDR), and a total of 78 (29.00%) isolates were drug resistant. OATB patients aged 40-49 years old (compared to those aged ≥70 years) and from the west of Hunan province, China (compared to those from the center of Hunan) were at risk for developing RR/MDR (ORs were 5.057 and 4.942, respectively; 95% CIs were 1.009-25.342 and 1.458-16.750, respectively). Conclusion: In South-central China, OATB mainly affected males, farmers and those aged 20-29 and 60-69 years old. Spinal TB is prone to occur in the lumbar and multiple spinal sites. The resistance situation of OATB was serious, and people aged 40-49 years old and patients from the west of Hunan were risk factors of RR/MDR. All these findings will help to improve the prevention, diagnosis and treatment strategies of OATB.

Transverse Spin Selectivity in Helical Nanofibers Prepared without Any Chiral Molecule.

In the last decade, chirality-induced spin selectivity (CISS) has undergone intensive study. However, there remain several critical issues, such as the microscopic mechanism of CISS, especially transverse CISS where electrons are injected perpendicular to the helix axis of chiral molecules, quantitative agreement between experiments and theory, and at which level the molecular handedness is key to the CISS. Here, we address these issues by performing a combined experimental and theoretical study on conducting polyaniline helical nanofibers which are synthesized in the absence of any chiral species. Large spin polarization is measured in both left- and right-handed nanofibers for electrons injected perpendicular to their helix axis, and it will be reversed by switching the nanofiber handedness. We first develop a theoretical model to study this transverse CISS and quantitatively explain the experiment. Our results reveal that our theory provides a unifying scheme to interpret a number of CISS experiments, quantitative agreement between experiments and numerical calculations can be achieved by weak spin-orbit coupling, and the supramolecular handedness is sufficient for spin selectivity without any chiral species.

Protein phosphatase 4 maintains the survival of primordial follicles by regulating autophagy in oocytes.

In mammalian ovary, the primordial follicle pool serves as the source of developing follicles and fertilizable ova. To maintain the normal length of female reproductive life, the primordial follicles must have adequate number and be kept in a quiescent state before menopause. However, the molecular mechanisms underlying primordial follicle survival are poorly understood. Here, we provide genetic evidence showing that lacking protein phosphatase 4 (PPP4) in oocytes, a member of PP2A-like subfamily, results in infertility in female mice. A large quantity of primordial follicles has been depleted around the primordial follicle pool formation phase and the ovarian reserve is exhausted at about 7 months old. Further investigation demonstrates that depletion of PPP4 causes the abnormal activation of mTOR, which suppresses autophagy in primordial follicle oocytes. The abnormal primordial follicle oocytes are eventually erased by pregranulosa cells in the manner of lysosome invading. These results show that autophagy prevents primordial follicles over loss and PPP4-mTOR pathway governs autophagy during the primordial follicle formation and dormant period.

Functional Verification of Transcription Factor comp54181_c0 in Monascus purpureus.

Monacolin K is a valuable secondary metabolite produced after a period of fermentation by Monascus purpureus; however, our current understanding of the regulatory mechanisms of its synthesis remains incomplete. This study conducted functional analysis on the key transcription factor, comp54181_c0, that is involved in the synthesis of monacolin K in Monascus. Mutant strains with either knockout or overexpression of comp54181_c0 were constructed using CRISPR/Cas9. A comparison between the knockout and overexpression strains revealed changes in fungal morphology and growth, with a significant increase in the production of Monascus pigments and monacolin K when comp54181_c0 was absent. Real-time fluorescence quantitative PCR analysis revealed that comp54181_c0 significantly influenced the transcription of key genes related to monacolin K biosynthesis in Monascus. In conclusion, our study elucidates the crucial role of comp54181_c0 in Monascus, enriches our understanding of fungal secondary metabolite development and regulation, and provides a foundation for the development and regulation of Monascus and monacolin K production.

Engineering Thermoresponsive Poly(N-isopropylacrylamide)-Based Films with Enhanced Stability and Reusability for Efficient Bone Marrow Mesenchymal Stem Cell Culture and Harvesting.

Poly(N-isopropylacrylamide) (PNIPAM) offers a promising platform for non-invasive and gentle cell detachment. However, conventional PNIPAM-based substrates often suffer from limitations including limited stability and reduced reusability, which hinder their widespread adoption in biomedical applications. In this study, PNIPAM copolymer films were formed on the surfaces of glass slides or silicon wafers using a two-step film-forming method involving coating and grafting. Subsequently, a comprehensive analysis of the films' surface wettability, topography, and thickness was conducted using a variety of techniques, including contact angle analysis, atomic force microscopy (AFM), and ellipsometric measurements. Bone marrow mesenchymal stem cells (BMMSCs) were then seeded onto PNIPAM copolymer films prepared from different copolymer solution concentrations, ranging from 0.2 to 10 mg·mL-1, to select the optimal culture substrate that allowed for good cell growth at 37 °C and effective cell detachment through temperature reduction. Furthermore, the stability and reusability of the optimal copolymer films were assessed. Finally, AFM and X-ray photoelectron spectroscopy (XPS) were employed to examine the surface morphology and elemental composition of the copolymer films after two rounds of BMMSC adhesion and detachment. The findings revealed that the surface properties and overall characteristics of PNIPAM copolymer films varied significantly with the solution concentration. Based on the selection criteria, the copolymer films derived from 1 mg·mL-1 solution were identified as the optimal culture substrates for BMMSCs. After two rounds of cellular adhesion and detachment, some proteins remained on the film surfaces, acting as a foundation for subsequent cellular re-adhesion and growth, thereby implicitly corroborating the practicability and reusability of the copolymer films. This study not only introduces a stable and efficient platform for stem cell culture and harvesting but also represents a significant advance in the fabrication of smart materials tailored for biomedical applications.

Stroke on ECG: a cerebral T-wave change secondary to acute carbon monoxide poisoning.

In clinical management of carbon monoxide (CO) poisoning, serum cardiac enzyme biomarkers and electrocardiogram (ECG) are both highly recommended emergency check-ups to evaluate myocardial injuries. Medical imaging - including head CT or MRI - are not routine for CO poisoning emergency management. We herein report on a comatose patient who was diagnosed with cerebral infarction secondary to 24 hours previous acute CO poisoning, warned by a typical cerebral-type T waves on ECG in advance, and confirmed by a head MRI. Fortunately, the patient made a full recovery based on a timely treatment with medications and hyperbaric oxygen (HBO2) therapy. We would like to propose that a vital, stable, conscious CO poisoning patient who remains a higher risk for hemorrhagic or ischemic stroke should be closely monitored for potential neurological abnormalities, and a continuous ECG monitoring should be reinforced throughout the treatment. A head MRI or CT is a priority in evaluating the secondary cerebral stroke and should be arranged immediately in the event of an abnormal ECG or if unusual new symptoms are apparent.

Returning from the afterlife? Sotorasib treatment for advanced KRAS mutant lung cancer: A case report.

BACKGROUND: Lung cancer is increasing in incidence worldwide, and targeted therapies are developing at a rapid pace. Furthermore, the KRAS specific gene is strongly associated with non-small cell lung cancer (NSCLC). Adult patients with locally advanced or metastatic NSCLC who have tested positive for the KRAS G12C mutation and have progressed after at least one systemic treatment are treated with sotorasib. CASE SUMMARY: In this study, we report on an advanced NSCLC with a KRAS G12C mutation. The histological diagnosis indicates stage IVB left lung adenocarcinoma with pelvic and bone metastases, identified as cT4N2bM1c. Using circulating tumor DNA analysis, it was possible to determine the mutation abundance of the KRAS gene exon 2, c.34G>Tp.G12C, which was 32.3%. The patient was advised to take sotorasib as part of their treatment. The imaging data were compared before and after treatment. Furthermore, clinical reassessments and regular serial blood testing were conducted. We found that the patient's clinical symptoms significantly improved after receiving sotorasib medication, and there were no notable side effects, such as liver toxicity, during the treatment. CONCLUSION: Sotorasib has shown promising clinical efficacy in patients with the KRAS G12c mutation and has no apparent toxic side effects.

Development and validation of a machine-learning model for predicting postoperative pneumonia in aneurysmal subarachnoid hemorrhage.

Pneumonia is a common postoperative complication in patients with aneurysmal subarachnoid hemorrhage (aSAH), which is associated with poor prognosis and increased mortality. The aim of this study was to develop a predictive model for postoperative pneumonia (POP) in patients with aSAH. A retrospective analysis was conducted on 308 patients with aSAH who underwent surgery at the Neurosurgery Department of the First Affiliated Hospital of Soochow University. Univariate and multivariate logistic regression and lasso regression analysis were used to analyze the risk factors for POP. Receiver operating characteristic (ROC) curve, calibration curve, and decision curve analysis (DCA) were used to evaluate the constructed model. Finally, the effectiveness of modeling these six variables in different machine learning methods was investigated. In our patient cohort, 23.4% (n = 72/308) of patients experienced POP. Univariate, multivariate logistic regression analysis and lasso regression analysis revealed age, Hunt-Hess grade, mechanical ventilation, leukocyte count, lymphocyte count, and platelet count as independent risk factors for POP. Subsequently, these six factors were used to build the final model. We found that age, Hunt-Hess grade, mechanical ventilation, leukocyte count, lymphocyte count, and platelet count were independent risk factors for POP in patients with aSAH. Through validation and comparison with other studies and machine learning models, our novel predictive model has demonstrated high efficacy in effectively predicting the likelihood of pneumonia during the hospitalization of aSAH patients.

Exploring m6A methylation in skin Cancer: Insights into molecular mechanisms and treatment.

N6-methyladenosine (m6A) is the most common and prevalent internal mRNA modification in eukaryotes. m6A modification is a dynamic and reversible process regulated by methyltransferases, demethylases, and m6A binding proteins. Skin cancers, including melanoma and nonmelanoma skin cancers (NMSCs), are among the most commonly diagnosed cancers worldwide. m6A methylation is involved in the regulation of RNA splicing, translation, degradation, stability, translocation, export, and folding. Aberrant m6A modification participates in the pathophysiological processes of skin cancers and is associated with tumor cell proliferation, invasion, migration, and metastasis during cancer progression. In this review, we provide a comprehensive summary of the biological functions of m6A and the most up-to-date evidence related to m6A RNA modification in skin cancer. We also emphasize the potential clinical applications in the diagnosis and treatment of skin cancers.

Targeting Decidual CD16+ Immune Cells with Exosome-Based Glucocorticoid Nanoparticles for Miscarriage.

Immune dysfunction in early pregnancy including overactivation of cytotoxic CD16+ NK cells and proinflammatory M1 macrophages at the maternal-fetal interface interferes with trophoblast invasion, spiral artery remodeling, and decidualization, potentially leading to miscarriage. Immunosuppressants like glucocorticoids (GCs) are used to regulate the immune microenvironment in clinical treatment, but the lack of safe and efficient tissue-specific drug delivery systems, especially immune cell-specific vectors, limits their widespread clinical application. Here, a previously uncharacterized delivery system is reported, termed GC-Exo-CD16Ab, in which GCs are loaded into purified exosomes derived from human umbilical cord mesenchymal stem cells, and subsequently decorated with antibody CD16Ab. GC-Exo-CD16Ab is biocompatible and has remarkable delivery efficiency toward CD16+ decidual natural killer (NK) cells and CD16+ macrophages in mice. This innovative approach effectively suppresses the cytotoxicity of decidual NK cells, inhibits M1 macrophage polarization, and regulates the decidual microenvironment, thereby enhancing placental and fetal morphology, and ultimately mitigating miscarriage risk in the abortion-prone mice. The developed GC-Exo-CD16Ab provides a feasible platform for precise and tissue-specific therapeutic strategies for miscarriage and pregnancy-related diseases.

Immunogenicity and biodistribution of lipid nanoparticle formulated self-amplifying mRNA vaccines against H5 avian influenza.

This study reports on the immunogenicity and biodistribution of H5 hemagglutinin (HA)-based self-amplifying (sa) mRNA vaccines in mice. Four sa-mRNA vaccines encoding either a secreted full-length HA, a secreted HA head domain, a secreted HA stalk domain, or a full-length membrane-anchored HA were investigated. All vaccines elicited an adaptive immune response. However, the full-length HA sa-RNA vaccines demonstrated superior performance compared to head and stalk domain vaccines. The antibody titers positively correlated with the vaccine dose. Cellular immune responses and antigen-specific IgA antibodies in the lungs were also observed. The comparison of the sa-mRNA vaccines encoding the secreted and membrane-anchored full-length HA revealed that anchoring of the HA to the membrane significantly enhanced the antibody and cellular responses. In addition to the injection site, the intramuscularly injected sa-mRNA-LNPs were also detected in the draining lymph nodes, spleen, and to a lesser extent, in the lung, kidney, liver, and heart.

[Evaluation of the role of standardized periodontal probing training on the teaching of undergraduates using the Florida probe system].

PURPOSE: To evaluate the effect of standardized periodontal probing training on the teaching of periodontal clinical probing for undergraduates by using Florida probe system. METHODS: Twenty undergraduates who practiced in the Department of Periodontology of Changzhou Stomatological Hospital from May 2022 to November 2022 were selected as the study objects and randomly divided into two groups with 10 students in each group. The experimental group received standardized periodontal probing training, while the control group did not receive training. Two groups of students used the traditional probe and the Florida probe to probe the left and right half-mouth teeth of one patient. In addition, a periodontal specialist used Florida probe to conduct full oral examination of the same patient, and the results were compared with those of the two groups of students. SPSS 26.0 software package was used for statistical analysis of the obtained data. RESULTS: There was no significant difference of probing depth(PD) between undergraduates and periodontal specialist in the experimental group (P＞0.05), while there was significant difference in the control group (P＜0.05). In the control group, PD values in the anterior area were not statistically different from those of periodontal specialist (P＞0.05), while PD values in the posterior area were statistically different (P＜0.05). Both groups of patients reported that the Florida probe system was more comfortable. CONCLUSIONS: Standardized periodontal probing training is helpful to improve the clinical probing ability of undergraduates. The use of Florida probe system can not only evaluate the teaching effect, but also improve the comfort level of patients, which is worthy of further application in the teaching course of periodontal probing for undergraduates.

Retrospective analysis of molecular characteristics, risk factors, and outcomes in carbapenem-resistant Klebsiella pneumoniae bloodstream infections.

BACKGROUND: Klebsiella pneumoniae (KP) is the second most prevalent Gram-negative bacterium causing bloodstream infections (BSIs). In recent years, the management of BSIs caused by KP has become increasingly complex due to the emergence of carbapenem-resistant Klebsiella pneumoniae (CRKP). Although numerous studies have explored the risk factors for the development of CRKP-BSIs, the mortality of patients with KP-BSIs, and the molecular epidemiological characteristics of CRKP, the variability in data across different populations, countries, and hospitals has led to inconsistent conclusions. In this single-center retrospective observational study, we utilized logistic regression analyses to identify independent risk factors for CRKP-BSIs and factors associated with mortality in KP-BSI patients. Furthermore, a risk factor-based prediction model was developed. CRKP isolates underwent whole-genome sequencing (WGS), followed by an evaluation of microbiological characteristics, including antimicrobial resistance and virulence genes, as well as epidemiological characteristics and phylogenetic analysis. RESULTS: Our study included a total of 134 patients with KP-BSIs, comprising 50 individuals infected with CRKP and 84 with carbapenem-susceptible Klebsiella pneumoniae (CSKP). The independent risk factors for CRKP-BSIs were identified as gastric catheterization (OR = 9.143; CI = 1.357-61.618; P = 0.023), prior ICU hospitalization (OR = 4.642; CI = 1.312-16.422; P = 0.017), and detection of CRKP in non-blood sites (OR = 8.112; CI = 2.130-30.894; P = 0.002). Multivariate analysis revealed that microbiologic eradication after 6 days (OR = 3.569; CI = 1.119-11.387; P = 0.032), high Pitt bacteremia score (OR = 1.609; CI = 1.226-2.111; P = 0.001), and inappropriate empirical treatment after BSIs (OR = 6.756; CI = 1.922-23.753; P = 0.003) were independent risk factors for the 28-day mortality in KP-BSIs. The prediction model confirmed that microbiologic eradication after 6.5 days and a Pitt bacteremia score of 4.5 or higher were significant predictors of the 28-day mortality. Bioinformatics analysis identified ST11 as the predominant CRKP sequence type, with blaKPC-2 as the most prevalent gene variant. CRKP stains carried multiple plasmid-mediated resistance genes along with some virulence genes. Phylogenetic analysis indicated the presence of nosocomial transmission of ST11 CRKP within the ICU. CONCLUSIONS: The analysis of risk factors for developing CRKP-BSIs and the association between KP-BSIs and 28-day mortality, along with the development of a risk factor-based prediction model and the characterization of CRKP strains, enhances clinicians' understanding of the pathogens responsible for BSIs. This understanding may help in the timely administration of antibiotic therapy for patients with suspected KP-BSIs, potentially improving outcomes.