Objective: To explore identification and resistance characteristics of CAMP-negativeStreptococcus agalactiae. Methods : Using matrix-assisted laser desorption ionization time-of-flight mass spectrometry(MALDI-TOF MS) and the CAMP assay, 33 presumptive strains ofStreptococcus agalactiaewere identified. The CAMP-negative strains were further validated through 16S rDNA, while the CAMP factor encoding gene(cfb) was detected using real-time fluorescence quantitative polymerase chain reaction(qPCR). Antimicrobial susceptibility testing was conducted using the microbroth dilution method, and the resistance rates of CAMP-negative and CAMP-positive strains were compared. Results : Based on MALDI-TOF MS identification, all 33 strains were classified asStreptococcus agalactiae. Among them, 7 strains tested negative for CAMP were subsequently confirmed asStreptococcus agalactiaethrough 16S rDNA. The qPCR results indicated that, only 1 strain showedcfbpresence. The CAMP-negative and CAMP-positive strains were sensitive to penicillin G, cefepime, cefotaxime, vancomycin, and linezolid. The resistance rates of the former to chloramphenicol and tetracycline(28.57%, 85.71%) were slightly higher than the latter(15.38%, 57.69%), while the resistance rates to moxifloxacin, levofloxacin, and erythromycin(14.29%, 14.29%, 42.86%) were slightly lower than the latter(34.62%, 34.62%, 57.69%), but was not significant. Conclusion Drug risistance of CAMP-negativeStreptococcus agalactiaeis the same as CAMP-positive strains, but traditional CAMP assay andcfb-targeted qPCR can result in missed detections. MALDI-TOF MS offers a quick, simple, and accurate identification method that merits wider adoption.

Objective : To investigate the antagonistic activity of Lactococcus garvieae SHAMU-LG6 against Staphy- lococcus . Methods : VITEK 2 GP identification card , Microflex LT MALDI-TOF mass spectrometer and 16S rDNA amplification sequencing were used to identify the strain species . The antagonistic activity of L. garvieae SHAMU- LG6 against different Staphylococcus was detected by Oxford cup method for bacterial inhibition ; the antimicrobial active components were preliminarily isolated and purified by adsorption on XAD16 nonionic macroporous resin , gradient ethanol elution and rotary evaporation drying. Results : L. garvieae SHAMU-LG6 exhibited potent antago- nistic effect against methicillin-resistant Staphylococcus aureus , methicillin-susceptible S. aureus , S. epidermidis , S. saprophyticus , S. lugdunensis , S. hominis , S. capitis and S. warneri , with inhibitory indices of 3 . 3 , 3 . 0 , 4. 3 , 2. 0 , 4. 0 , 3 . 5 , 3 . 8 , and 3 . 5 , respectively. The antimicrobial active components produced by L. garvieae SHAMU-LG6 were mainly present in 70% and 80% ethanol eluates . Conclusion L. garvieae SHAMU-LG6 ex- hibits a potent antagonistic effect on Staphylococcus , and the antimicrobial active components produced by it are ex- pected to be a lead compound for the development of novel antimicrobial agents .

Objective : To explore the molecular characteristics of four CAMP negativeStreptococcus agalactiae(S.agalactiae) in whole genome sequencing. Methods : The identification of suspicious bacterial strains was conducted using matrix-assisted laser desorption ionization time-of-flight mass spectrometry(MALDI-TOF MS). For the strains confirmed asS.agalactiaethrough identification, further CAMP experiments were conducted. For CAMP negative strains, whole genome sequencing was performed using MGI DNBSEQ-T7 and MinION Flow Cell sequencing platforms. Subsequently, multi-locus sequence typing(MLST), virulence genes and resistance genes of the strains were compared and analyzed using various databases. Phoenix M50 fully automatic drug sensitivity analyzer was employed to determine the sensitivity of the bacterial strains to commonly used antibiotics. Results: Four CAMP-negativeS.agalactiaestrains were included. Whole-genome sequencing analysis revealed that all four CAMP-negativeS.agalactiaestrains belonged to the ST862 type. These strains harbored 22 virulence genes associated with capsular polysaccharides, β-hemolysin, and hyaluronidase, as well as seven resistance genes linked to macrolides, lincosamides, polypeptides, and aminoglycosides. Antimicrobial susceptibility testing revealed that CAMP-negativeS.agalactiaewas susceptible to penicillin G, cefepime, cefotaxime, and vancomycin. However, three strains exhibited resistance to erythromycin, and one strain demonstrated resistance to clindamycin. Conclusion Four CAMP negativeS.agalactiaeof the ST862 type possess multiple virulence and drug resistance genes, showing high resistance to erythromycin, warranting clinical attention.

Objective To investigate the efficacy of varying doses of methylprednisolone(MP)on mice with acute exacerbations of chronic obstructive pulmonary disease(AECOPD)induced with influenza A virus(IAV).Methods Mouse model of COPD was established using LPS combined with smoking for 12 weeks,and then these COPD mice were treated with administration of 40 μL IAV via nasal drip to establish a AECOPD model.A total of 15 AECOPD mice were randomly divided into low-,medium-and high-dose MP groups,oseltamivir group and blank group.The body weight and survival time were monitored within 10 d after IAV infection.On days 1,3,and 5 post-treatment,lung function was assessed using whole-body plethysmography(WBP),inflammatory factors in bronchoalveolar lavage fluid(BALF)were quantified with ELISA,viral titers in BALF were determined using plaque assays,and colony-forming units were evaluated with blood agar plates.Immunofluorescence analysis:① Pulmonary immunofluorescence assay:Mice were randomly categorized into(n=4):LPS 1-day group,LPS 3-day group,and LPS+MP treatment group.All groups received an initial dose of LPS via atomization;subsequently,the LPS+MP treatment group received a single gavage dose of MP.Lung tissues were harvested from the 1-day LPS group on 1 d post-treatment,and from the 3-day LPS and LPS+MP groups on 3 d for immunofluorescence staining.② Cellular immunofluorescence assay:Mouse bone marrow neutrophils were classified into blank control(no intervention),LPS stimulation(LPS group),MP intervention with LPS stimulation(LPS+MP group),and MP intervention alone(MP group).The above cells were collected in 4 h after corresponding interventions for subsequent cellular immunofluorescence analysis.Results ①The medium-dose MP group demonstrated the most significant improvement in survival rate,weight recovery,and lung function when compared to other groups(P＜0.05).② Treatment of medium-dose MP obviously reduced the levels of IL-6 and neutrophil extracellular traps(NETs)(P＜0.05),while,elevated inflammatory factors and NETs were observed in the high-dose MP group on day 5 post-treatment.③ Notable decline in the lung injury score was found in the medium-dose MP group than the other groups(P＜0.05).④The high-dose MP group exhibited substantial bacterial proliferation and delayed viral clearance since day 5 after treatment.Conclusion Medium-dose MP shows best efficacy in treatment of IAV-induced AECOPD,and the dose neither delays viral clearance nor increases the risk of bacterial infection following viral infection.

As a cheap and effective antibiotic,sulfonamides are often used in animal husbandry.However,their residues in animal-derived foodstuffs will threaten human health.Consequently,a high-performance liquid chromatography(HPLC)method integrated with supramolecular solvent microextraction was successfully established for simultaneous quantification of sulfonamide residues sulfachlorpyridazine,sulfamethoxazole,sulfamethoxypyridazine and sulfadimethoxine in milk matrices.This approach exhibited prominent characteristics of operational simplicity,environmental sustainability,and high extraction efficiency.The supramolecular solvents prepared by tributyl octylphosphine tetrafluoroborate and tetrahydrofuran were employed as extraction solvents.The analytes underwent isolation and concentration via dispersive liquid-liquid microextraction(DLLME)prior to quantitative determination using high-performance liquid chromatography(HPLC).The composition and microscopic morphology of the supramolecular solvent were characterized through a series of analytical techniques,including phase diagram,Fourier transform infrared spectroscopy,scanning electron microscopy,and inverted fluorescence microscopy and so on.The density and pH value of supramolecular solvents were determined.The extraction conditions were optimized through the one-factor experiments.The experimental results demonstrated that under the optimal extraction conditions,the four kinds of sulfonamide antibiotics exhibited excellent linearity within respective detection range(R2 ≥ 0.9998)and the limits of detection(LOD)were 0.67-1.45 μg/L.Compared with literature methods,this approach offered some advantages such as simplicity of operation and less reagent consumption,and could be used for analysis and detection of sulfonamide antibiotic residues in milk samples.The present method provided technical support for food safety regulation and paved a new way for the application of supramolecular solvents in the field of extraction and separation.

The major components of Olaflur raw material were characterized using ultra performance liquid chromatography-quadrupole time-of-flight-mass spectrometry(UPLC-Q-TOF/MS).The results revealed that cetyl amine fluoride(C16-AmF),octadecene amine fluoride(C18:1-AmF),and octadecyl amine fluoride(Olaflur)were the main components.The contents of C16-AmF,C18:1-AmF,and Olaflur in oral care products were determined via ultra performance liquid chromatography-charged aerosol detector coupled with solid-phase extraction(SPE-UPLC-CAD).The oral care sample was dispersed evenly with a 50%ethanol aqueous solution,and then vortexed with ethanol.The supernatant was collected by centrifugation,concentrated to near dryness,and redissolved with ultrapure water.The re-dissolved sample was loaded onto a Poly-Sery HLB Pro SPE column for purification and elution.The acetonitrile eluate was collected and concentrated to 1.0 mL.Finally,a prepared test solution was separated on a Thermo Acclaim Surfactant Plus chromatographic column(2.1 mm×150 mm,3 μm).Acetonitrile and 100 mmol/L acetic acid-ammonium acetate aqueous solution(pH=4.8)were used as the mobile phases for gradient elution.The flow rate was 0.3 mL/min and cloumn temperature was maintained at 40℃.The sample was detected using a charged aerosol detector,and quantified using an external standard method.The experimental results indicated that the three organic fluorinated amines showed good linear relationship in their respective concentration ranges.The correlation coefficients(r)were greater than 0.99.The limit of detection(LOD)and the limit of quantification(LOQ)of C16-AmF were 2.0 and 8.0 μg/mL,respectively.The LOD and LOQ of C18:1-AmF were 2.0 and 8.0 μg/mL,respectively.The LOD and LOQ of Olaflur were 3.0 μg/mL and 10.0 μg/mL,respectively.The spiked recoveries of the three organic fluorinated amines were 84.3%-104.2%,with relative standard deviations(RSDs)of 4.93%-5.82%.The 28 batches of commercial oral care samples were detected by this method and the results indicated that three organic fluorinated amines were detected in 18 samples and the total content were 22.2-11477.8 μg/g.This method had high sensitivity and good reproducibility.It was suitable for verifying the authenticity of the claims of oral care products promoted with Olaflur as the main efficacy ingredient and selling point,and provided a valuable reference for establishing and improving the standard analytical method for Olaflur.

Urinary system tumors are very common nowadays，including prostate cancer，renal cancer，bladder cancer，and urothelial carcinoma.In recent years，the incidence of these tumors has been on the rise.This paper briefly summarizes the emerging technologies explored by West China Hospital in recent years for urinary system tumors，such as gene sequencing analysis，radiomics and big data，liquid chromatography-mass spectrometry，multi-modal intelligent fusion diagnostic technology，surgical decision-making tools built with artificial intelligence and big data，mRNA vaccines，combination of targeted and immune therapies，and irreversible electroporation technology.These technologies provide strong support and point out the ways for the prevention，early diagnosis，and individualized treatment of urinary system tumors.

Objective : To investigate the causes of false negative results in the detection of Streptococcus agalactiae using fluorescent quantitative PCR(qPCR) targeting the CAMP factor gene(cfb),and to perform a comprehensive analysis of the associated molecular mechanisms. Methods: A total of 76 vaginal secretion samples were evaluated using both qPCR based on cfb gene and bacterial culture methods. Four suspicious strains exhibiting negative qPCR results but positive culture findings were identified using matrix-assisted laser desorption ionization time-of-flight mass spectrometry(MALDI-TOF MS),latex agglutination antigen detection,and the CAMP test. Whole genome analysis was conducted utilizing the MGI DNBSEQ-T7 and Nanopore-PromethION 48 sequencing platforms. Phylogenetic and circular evolutionary trees were constructed using the 16S rRNA gene for strain verification. Multilocus sequence typing(MLST) was conducted,and cfb sequences were aligned and analyzed based on spliced sequences and original data. Specific primers targeting the cfb gene were designed for full-length amplification,followed by verification through agarose gel electrophoresis. Results: The four strains identified as suspicious were classified as S. agalactiae through MALDI-TOF MS,antigen detection,and 16S rRNA gene analysis,with MLST typing indicating ST-862. Phenotypic analysis revealed a negative CAMP test. Whole genome sequence alignment failed to detect the cfb gene or any homologous sequences,and molecular testing confirmed the absence of cfb gene PCR amplification products,thereby confirming its complete deletion. Conclusion This deletion is identified as the molecular mechanism responsible for the false negative qPCR detection of S. agalactiae when targeting this specific gene.It is recommended that the qPCR detection targeting a single cfb gene has limitation,and this may impact clinical diagnosis and treatment decisions. This limitation warrants carefulconsideration.

Objective: To investigate the hemolytic phenotypes of Staphylococcus aureus clinical isolates． Methods: The hemolytic phenotypes of 105 Staphylococcus aureus isolates were analyzed and summarized using the three-point inoculation method．Real-time fluorescence quantitative PCR was used to measure the mRNA expression levels of four hemolysin genes (hla，hlb，hlc，and hld) ; The VITEK 2 GP639 antimicrobial susceptibility card was used to detect resistance to commonly used antibiotics ; DNA gel electrophoresis was performed to determine the prevalence of the mecA，sea，tst，and pvl genes ; The microtiter plate crystal violet staining method was used to assess biofilm formation ability ; The CCK-8 assay was used to evaluate cytotoxicity against macrophages． Results: Seven hemo- lytic phenotypes were identified among the Staphylococcus aureus clinical isolates． Differences were found among Staphylococcus aureus clinical isolates with different hemolytic phenotypes in terms of mRNA expression levels of he- molysin genes，antibiotic resistance，virulence gene prevalence，biofilm formation ability，and cytotoxicity to mouse macrophages (P ＜0. 05 ) ． Conclusion Staphylococcus aureus clinical isolates exhibit diverse hemolytic pheno- types，which should be a focus across multiple dimensions，including microbiological testing，clinical treatment， and nosocomial infection prevention and control．

In recent years,viral vector-mediated chimeric antigen receptor(CAR)cell therapy has emerged as a prominent topic in the field of cancer treatment and has demonstrated significant clinical efficacy in patients with hematological malignancies.However,the permanent expression of CAR induced by this therapy may give rise to severe adverse reactions.In contrast,messenger RNA(mRNA)chimeric antigen receptor therapy is anticipated to become a new generation of safer and more effective treatments due to its lack of insertional mutagenesis and minimal risk of off-tar-get toxicity.This therapeutic approach involves transfecting effector immune cells with CAR-en-coding mRNA to elicit an immune response within the body.It has been employed for treating B-cell malignancies,lymphoma,acute myelogenous leukemia(AML),and other cancers.The continuous optimization of mRNA purification,modification,and transfection technology enhances CAR ex-pression durability,while increasing killing efficiency and expanding the range of action.This pa-per reviews the research advances on CAR-encoding mRNA delivery,its application and advan-tages in cancer therapies.