ObjectiveTo explore the mechanism by which the ethanol extract of Epimedium brevicornu （EEBM） intervenes in mesenchymal adipose-derived stem cells （ADSCs） to delay aging in castrated rats. MethodsForty-five 3-month-old SPF female SD rats were ovariectomized and randomly divided into model group， ADSCs treatment group， and ADSCs groups treated with low， medium， and high concentrations of EEBM （1， 50， 100 μg·L^-1）， referred to as the AE low， medium， and high concentration groups， with 9 rats in each group. After tail vein injection of 200 μL of the corresponding stem cell suspension， aging-related indicators including cyclin-dependent kinase inhibitor （p21）， tumor suppressor gene （p53）， interleukin-6 （IL-6）， interleukin-8 （IL-8）， superoxide dismutase （SOD）， malondialdehyde （MDA）， B-cell lymphoma-2 （Bcl-2）， Bcl-2-associated X protein （Bax）， cysteine-aspartic acid protease-3 （Caspase-3）， and lipofuscin were measured using enzyme-linked immunosorbent assay （ELISA） and Western blot. ResultsCompared with the model group， the IL-6 content in the AE low， medium， and high concentration groups was significantly decreased （P<0.05）. Lipofuscin， MDA， and IL-8 levels in the ADSCs treatment group and AE low， medium， and high concentration groups were significantly reduced （P<0.01）， while SOD content was significantly increased （P<0.05， P<0.01）. Compared with the ADSCs treatment group， lipofuscin and IL-8 levels in the AE low， medium， and high concentration groups were significantly reduced （P<0.05， P<0.01）. The MDA content was significantly decreased in the AE medium concentration group （P<0.01）. Compared with the model group， protein levels of p21， p53， Bax， and Caspase-3 in the ADSCs treatment group and AE low， medium， and high concentration groups were significantly reduced （P<0.05， P<0.01）， while the Bcl-2 protein level was significantly increased （P<0.01）. Compared with the ADSCs treatment group， protein levels of p21， p53， Bax， and Caspase-3 in the AE low， medium， and high concentration groups were significantly reduced （P<0.05， P<0.01）， and the Bcl-2 protein level in the AE low concentration group was significantly increased （P<0.01）. ConclusionThe results of this experiment show that EEBM-treated ADSCs or ADSCs may delay aging in castrated rats by inhibiting cell apoptosis， reducing cell cycle inhibitors and pro-inflammatory factors， enhancing antioxidant capacity， and reducing oxidative reactions. Moreover， EEBM-treated ADSCs demonstrate stronger anti-aging effects than ADSCs alone. This study provides experimental evidence supporting the clinical use of EEBM to intervene in ADSCs and delay aging.

ObjectiveTo conduct an epidemiological investigation, isolate and identify the pathogenic bacteria, and perform whole-genome sequencing (WGS) analysis of a food poisoning outbreak in Suzhou High-tech Zone, so as to provide references for the prevention and management of similar incidents. MethodsAn epidemiological investigation was carried out on affected individuals and restaurant staff. Multi-pathogen screening was performed on rectal swab samples from affected cases and restaurant staff, as well as on environmental swab samples from food preparation areas and retained food samples. WGS was performed on the pathogens isolated from the samples. ResultsA total of 15 cases were identified through hospital visit record reviews and on-site inquiries. Of the 15 case samples, 14 tested positive for Staphylococcus aureus (SA). In addition, 3 out of 15 staff samples and 6 out of 34 retained food samples tested positive for SA. WGS results revealed that the 6 food-derived isolates and 13 case-derived isolates shared the same sequence type (ST), Staphylococcal Protein A (SPA) type, and enterotoxin gene profile, with whole-genome single nucleotide polymorphism (wgSNP) differences of ≤5. Two novel SA sequence types: ST9159 and ST9161, were also identified in this study. ConclusionThis food poisoning outbreak is caused by contamination food with SA harbouring the seb and sec enterotoxin genes. The primary causes of contamination and cross-contamination included improper food handling practices, the use of the same utensils for raw and cooked foods, and extended storage of certain dishes at room temperature. Strengthening sanitary supervision in food handling facilities is crucial for reducing the occurrence of similar incidents.

Objective To develop a double-antibody sandwich ELISA for the detection of varicella-zoster virus(VZV)-ORF7 protein,and verify the method for the detection of ORF7 antigen across manufacturing stages of live attenuated varicella vaccine Oka-7S strain.Methods Recombinant plasmid pET-28a-ORF7 was used to induce prokaryotic expression of VZVORF7 protein,which was then purified by Ni~(2+) affinity chromatography column.Using ORF7 prokaryotic protein as the immunogen,the hybridoma cell lines were screened by mouse hybridoma fusion technique,and the monoclonal antibodies(mAbs)were prepared.The antibody titer was detected by indirect ELISA,and the antibody specificity was identified by Western blot.The antigenic epitopes of mAbs were analyzed by ELISA,and the double-antibody sandwich ELISA for VZV-ORF7antigen was developed by antibody pairing screening.The sensitivity,specificity and repeatability of the method were verified,and three batches of VZV Oka-7S harvested samples were detected by using the developed method.Results Four hybridoma cell lines steadily secreting anti-VZV-ORF7 specific antibodies,named M2B5,M2G5,8C2 and 1C4,were produced.The antibody titers of culture supernatant and mouse ascites were 10~4-10~5 and 10~6-10~7,respectively.The purity of purified mAbs was both about 97% in reduced and non-reduced states.All the four mAbs exhibited specific binding to VZV whole virus protein and purified ORF7 prokaryotic protein.M2G5 was selected as the capture antibody and M2B5-HRP as the enzyme-labeled antibody,with the optimum working concentrations of 4 μg/mL and 1:8 000,respectively.The cutoff value was 0.111,and when A_(450)≥0.111,it was determined as positive and <0.111 as negative.The linear range of this method was 3.9-250 ng/mL with a four-parameter fit,and the standard curve equation was y=(0.049 5-2.24)/(1+x/97.8)~(1.27)+2.24,R~2=0.999,with the limit of detection of 2.2 ng/mL.There was no cross-reaction with tetravalent influenza virus split vaccine,mumps virus and measles virus.In addition,the intra-assay and inter-assay CVs of repeatability were all less than 10%.Three batches of VZV Oka-7S strains were all detected to be negative,and the coincidence rate was 100%.Conclusion The developed double-antibody sandwich ELISA against VZV-ORF7 has high sensitivity,good specificity and high repeatability,and can be used for the rapid detection of VZV-ORF7 protein and VZV Oka and Oka-7S strains.

Mental state is an important part of the normal life activities of the human body, and it is also the most external expression and the most easily obtained information of the physical condition. The normal activities of the mind depend on the normal operation of the viscera, qi, and blood, and are a unified whole that prospers together and suffers together. The theory of the five-spirit-viscera in the Yellow Emperor’s Inner Classic revealed that the normal mental activities of the human body were dominated by the five internal organs, that is, the five internal organs were the body and the five spirits were the function. And it highlighted the viewpoint that the five internal organs store the spirits and are actually one. The heart governs the spirit and belongs to the four internal organs. On this basis, Synopsis of Golden Chamber used the internal organs to diagnose and treat mental diseases, integrating the theory of the five spirits into it, forming a unique method of diagnosis and treatment with the heart as the leading factor and regulating the qi and blood of the four internal organs. It identified the pathogenesis of diseases such as pathogenic crying, lily disease, and hysteria from five levels: heart deficiency and weak qi, heart-lung disharmony, heart-liver disharmony, the heart of the loss of the spleen nourishment, and disharmony between heart and kidney. The treatment was mainly to replenish the deficiency of the viscera and eliminate the pathogens, reflecting the characteristics of regulating the mind and calming the four internal organs. This unique view on diagnosis and treatment has profoundly influenced the diagnosis and treatment theories of mental illnesses by later doctors, and is of great significance to the current clinical treatment of such illnesses.

ObjectiveTo investigate the significance of different non-treatment thresholds or upper limits of normal （ULN） of alanine aminotransferase （ALT） in evaluating significant liver pathological injury in patients with chronic hepatitis B virus （HBV） infection， and to provide guidance for clinical diagnosis and treatment. MethodsThis study was conducted among 733 patients with chronic HBV infection who were hospitalized in Ningbo No. 2 Hospital from January 2015 to December 2023 and underwent liver biopsy and histopathological examination， and all patients had a persistent ALT level of ≤40 U/L and positive HBV DNA （>30 IU/mL）. According to the treatment threshold or ULN of ALT， the patients were divided into group 1 with 575 patients （≤35 U/L for male patients， ≤25 U/L for female patients）， group 2 with 430 patients （≤30 U/L for male patients， ≤19 U/L for female patients）， group 3 with 443 patients （≤27 U/L for male patients， ≤24 U/L for female patients）， group 4 with 446 patients （≤25 U/L）， group 5 with 158 patients （>35 U/L for male patients， >25 U/L for female patients）， and group 6 with 145 patients （>30 — ≤35 U/L for male patients， >19 — ≤25 U/L for female patients）. Groups 2， 5， and 6 were compared to analyze the severity of liver pathological injury in patients with different ALT levels and the constituent ratio of patients with significant liver pathological injury， and groups 1， 2， 3， and 4 were compared to investigate the value of different ULN or non-treatment thresholds of ALT in determining liver inflammation grade （G）， liver fibrosis stage （S）， and the treatment indication based on liver pathology. The independent-samples t test was used for comparison of normally distributed continuous data between two groups； a one-way analysis of variance was used for comparison between multiple groups， and the least significant difference t-test or the Tambane’s test was used for further comparison between two groups； the Mann-Whitney U test was used for comparison of non-normally distributed continuous data between two groups， and the Kruskal-Wallis H test was used for comparison between multiple groups and further comparison between two groups； the chi-square test or the Fisher’s exact test was used for comparison of categorical data between groups； a Ridit analysis was used for comparison of ranked data. A multivariate Logistic regression analysis （forward stepwise） was performed with whether liver pathology met the treatment indication （≥G2 and/or ≥S2） as the dependent variable and related factors with a significant impact on the dependent variable （P <0.05） as the independent variable. The receiver operating characteristic （ROC） curve was plotted， and the area under the ROC curve （AUC）， as well as sensitivity， specificity， positive predictive value， negative predictive value， positive likelihood ratio， and negative likelihood ratio， was used to assess the diagnostic value of different non-treatment thresholds of ALT. ResultsAmong the 733 patients， 259 （35.33%） had ≥G2 liver inflammation， 211 （28.79%） had ≥S2 liver fibrosis， and 306 （41.75%） had treatment indication （≥G2 and/or ≥S2）. There was a significant difference in liver inflammation grade （G0 — G4） between groups 2， 5， and 6 （χ²=22.869， P <0.001）， and there were also significant differences in the constituent ratios of patients with ≥G2 or ≥G3 liver inflammation between the three groups （χ²=21.742 and 14.921， P<0.001 and P=0.001）. There was a significant difference in liver fibrosis stage （S0 — S4） between groups 2， 5， and 6 （χ²=16.565， P<0.001）， and there were also significant differences in the constituent ratios of patients with ≥S2， ≥S3 or S4 liver fibrosis between the three groups （χ²=13.264， 13.050， and 6.260， P=0.001， 0.001， and 0.044）. There were significant differences between groups 2， 5， and 6 in the constituent ratios of patients with or without treatment indication based on liver pathology （χ²=20.728， P<0.001）. There were significant differences between groups 2， 5， and 6 in the constituent ratio of male patients （χ²=24.836， P<0.05）， age （F=5.710， P<0.05）， ALT （F=473.193， P<0.05）， aspartate aminotransferase （AST） （F=107.774， P<0.05）， ALT/AST ratio （F=40.167， P<0.05）， γ-glutamyl transpeptidase （GGT） （H=15.463， P<0.05）， aspartate aminotransferase-to-platelet ratio index （APRI） （H=63.024， P<0.05）， and LIF-5 （5 indicators for liver inflammation and fibrosis） （H=46.397， P<0.05）. In groups 1 — 4， compared with the patients without treatment indication， the patients with treatment indication had a significantly lower constituent ratio of patients with positive HBeAg， significantly lower levels of platelet count （PLT） and HBV DNA， and significantly higher age， ALT， AST， GGT， APRI， FIB-4， and LIF-5 （all P<0.05）. The Logistic regression analysis showed that age （odds ratio ［OR］=1.044， 95% confidence interval ［CI］： 1.025 — 1.063， P<0.001）， GGT （OR=1.022， 95%CI： 1.007 — 1.038， P=0.003）， and HBV DNA （OR=0.839， 95%CI： 0.765 — 0.919， P<0.001） were influencing factors for treatment indication based on liver pathology in group 1； HBeAg （OR=1.978， 95%CI： 1.269 — 3.082， P=0.003）， age （OR=1.048， 95%CI： 1.025 — 1.071， P<0.001）， GGT （OR=1.016， 95%CI： 1.001 — 1.031， P=0.041）， and PLT （OR=0.995， 95%CI： 0.991 — 1.000， P=0.049） were influencing factors in group 2； age （OR=1.040， 95%CI： 1.014 — 1.066， P=0.002）， ALT （OR=1.047， 95%CI： 1.005 — 1.092， P=0.029）， HBV DNA （OR=0.817， 95%CI： 0.736 — 0.907， P<0.001）， and LIF-5 （OR=7.382， 95%CI： 1.151 — 47.330， P=0.035） were influencing factors in group 3； age （OR=1.054， 95%CI： 1.031 — 1.077， P<0.001）， ALT （OR=1.061， 95%CI： 1.016 — 1.107， P=0.008）， and HBV DNA （OR=0.825， 95%CI： 0.743 — 0.917， P<0.001） were influencing factors in group 4. The diagnostic performance for identifying ≥G2 liver inflammation， ≥S2 liver fibrosis， and treatment indication in groups 1 — 4 had an AUC of >0.7； group 1 showed the lowest sensitivity （28.76%） and the highest specificity， positive predictive value， positive likelihood ratio， and negative likelihood ratio in judging treatment indication； group 2 had the highest sensitivity and negative predictive value and the lowest negative likelihood ratio； groups 3 and 4 had similar diagnostic indicators. ConclusionIn patients with chronic HBV infection and a persistently low ALT level， the severity of liver histopathological injury and the constituent ratio of significant liver histopathological injury decrease with the reduction in ALT level. A higher non-treatment threshold or ULN of ALT can help to identify the patients requiring treatment （with a higher specificity）， while a lower non-treatment threshold or ULN of ALT can help to identify the patients who do not require treatment （with a higher sensitivity）.

Objective To investigate the effect of growth hormone(GH)pretreatment on the improvement of eu-ploid and pregnancy outcome.Methods A prospective analysis was conducted on 134 patients undergoing preim-plantation genetic testing for aneuploidy(PGT-A),among whom 30 patients were self-controlled and 104 patients were inter-group controlled.According to whether GH was added,the patients were divided into GH pretreatment group and GH non-pretreatment group.GH pretreatment included subcutaneous injection of GH 2U/day for 4-6 weeks before the start of gonadotropin(Gn),and the dose was doubled on the day of Gn until the trigger day.GH non-pretreatment meant no GH treatment,GH pretreatment was given when the previous PGT-A cycle failed within one year when the PGT-A was performed again,forming the self-control group.The basic situation,blastocyst situa-tion and pregnancy outcome were compared between the groups by inter-group and self-control.Results No matter in the group control or self-controlled group,the endometrial thickness on the day of HCG,ovarian sensitivity index(OSI),number of oocytes obtained,MII oocytes,2PN number,2PN fertilization rate,available oocyte rate,num-ber of biopsy blastocysts,number of euploid blastocysts,euploid blastocyst rate,and at least one euploid rate sig-nificantly increased after GH pretreatment,with statistically significant differences(P＜0.05).The total amount of Gn,Gn days,number of mosaic blastocysts,and mosaic blastocyst rate were not significantly changed after GH pretreatment,with no statistically significant differences.The implantation rate and clinical pregnancy rate in-creased after GH pretreatment,but with no statistically significant differences.Conclusion GH pretreatment can significantly improve the number and rate of euploid embryos in patients undergoing PGT-A,and has a tendency to improve pregnancy outcome.

bjective　To analyze the drug resistance screening status and drug resistance influencing factors of high-risk groups of drug-resistant pulmonary tuberculosis in Qingdao, and to understand the inclusion of rifampicin patients in treatment, so as to provide a reference for the prevention and treatment of drug-resistant pulmonary tuberculosis. Methods　The medical records of 726 cases of drug-resistant pulmonary tuberculosis among high-risk populations registered in Qingdao from 2018 to 2022 were obtained from the National Health Insurance Information System of the China Center for Disease Control and Prevention. The drug resistance to five anti-tuberculosis drugs, namely isoniazid (INH), rifampicin (RFP), ethambutol (EMB), levofloxacin (Lfx), and amikacin (Am), in the high-risk populations of drug-resistant pulmonary tuberculosis was analyzed. Univariate and multivariate logistic regression were used toidentify factors influencing rifampicin resistance, and the detection and inclusion of treatment for rifampicin-resistant patients were evaluated. Results　Of the 726 subjects, 278 were drug-resistant, with a total drug resistance rate of 38.29%. The drug resistance for the five anti-tuberculosis drugs in descending order was: INH 25.90%(188/726), RFP 22.87%(166/726), Lfx 14.19%(103/726), EMB 11.29%(82/726), Am 2.48%(18/726). Analysis of the drug resistance spectrum showed that among those resistant to one drug, RFP was most common, accounting for 13.67% (38/278); among those resistant to two drugs, INH+RFP was predominant, accounting for 15.83% (44/278); among those resistant to three drugs, INH+RFP+Lfx was most frequent, at 7.19% (22/278); and among those resistant to four drugs, INH+RFP+EMB+Lfx was highest, at 6.12% (17/278). Multivariate logistic regression analysis of rifampicin resistance showed that compared with patients under 25 years of age, the risk of developing rifampicin resistance was lower in the groups aged 45 to under 65 and those aged 65 and above (OR=0.356, 95%CI: 0.181-0.700; OR=0.352, 95%CI: 0.170-0.729). Compared with migrant patients in other provinces, local patients from within the same county or district had a lower risk of developing rifampicin resistance (OR=0.599, 95%CI:0.383-0.962). Compared with patients who were smear-positive at the end of the second month of initial treatment, the risk of developing rifampicin resistance was higher in patients with relapse/return, failure of retreatment/chronic, and other categories of patients (OR=9.380, 95%CI:3.717-23.671;OR=25.749, 95%CI:8.037-82.490; OR=36.651, 95%CI:8.438-159.201). Conclusions　The situation of drug-resistant pulmonary tuberculosis in Qingdao cannot be ignored. Individuals under 25 years old, migrants from other provinces, and patients with relapse/return, failure of retreatment/chronic, and other categories are significant risk factors for developing rifampicin resistance in the high-risk groups of drug-resistant pulmonary tuberculosis.

Objective:To observe the clinical and imaging features of patients with retinal vein occlusion (RVO) complicated with retinal artery occlusion (RAO).Methods:A retrospective clinical study. Fifteen patients with 15 eyes with RVO combined with RAO and macular edema diagnosed by ophthalmology examination in the Department of Ophthalmology, First People's Hospital of Xianyang City during 2 years from February 1, 2022 to January 31, 2024 were included in the study. Branch retinal vein occlusion (BRVO) combined with branch retinal artery occlusion (BRAO) occurred in 3 cases and 3 eyes. Central retinal vein occlusion (CRVO) complicated with central retinal artery occlusion (CRAO) in 12 eyes. Best corrected visual acuity (BCVA), intraocular pressure, scanning laser ophthalmoscope, optical coherence tomography (OCT), fluorescein fundus angiography (FFA) and serum homocysteine were all performed. OCT angiography (OCTA) was performed in 6 eyes. All eyes were treated with intravitreal injection of anti-vascular endothelial growth factor drugs. After the initial 1 treatment, dosage was assessed as needed. Follow-up was performed every month for 12 months after treatment. FFA inspection was performed at 3 months. During follow-up, it was found that there were no perfusion areas of capillaries, and retinal laser photocoagulation therapy was given in time. Fundus manifestations, FFA, OCT, OCTA characteristics and causes of disease were analyzed retrospectively.Results:There were 15 eyes in 15 cases, 9 eyes in 9 males; 6 women with 6 eyes. Age was (61.0±9.7) years. All complained of painless vision loss in one eye. All eyes were positive for relative afferent pupillary disorder. Contralateral congenital optic disc defect was in 1 case; hypertension was in 6 cases; hyperhomocysteinemia was in 2 cases; cerebral infarction was in 3 cases; coronary heart disease was in 1 case. CRVO combined with CRAO was in 12 eyes BCVA light sensitivity-0.25. The BCVA of BRVO combined with BRAO were 0.1, 0.4 and 0.25, respectively. All the patients had retinal edema in the posterior pole of the eye, venous sinuous, dilated, thin arteries and stiff shape. The retina presents with flaky or flame-like bleeding. Posterior polar retinal lint patch was in 13 eyes. In 12 eyes with CRVO combined with CRAO, optic disc edema was observed and the boundary was not clear. In 3 eyes with BRVO combined with BRAO, no obvious abnormality was found in the optic disc, and the boundary was clear. FFA examination showed no or prolonged arterial filling, delayed retinal vein laminar flow, relatively slow or even no capillary filling, macular arteriole atretosis to varying degrees, arch ring structure destruction, optic disc telangiectasia and fluorescein leakage. OCT examination showed that the middle and inner layers of the retina were thickened to varying degrees, the diffuse reflex was enhanced, the interlayer structure was unclear, and the reflex of the lower retinal tissue was weakened. The blood flow density of superficial capillary plexus and deep capillary plexus (DCP) decreased in 6 eyes undergoing OCTA examination. Decreased or interrupted blood flow in the vascular bed of DCP. During the follow-up period, there were 13 eyes with no perfusion area of retinal capillary. The time of occurrence was (1.14±0.95) (0-2) months, and the area was 10-75 disc area. Optic nerve atrophy occurred in 5 eyes. At the last follow-up, visual acuity increased, unchanged and decreased in 12, 2 and 1 eyes, respectively.Conclusions:The pathogenesis of RVO-RAO is complicated. Most RVO and RAO occurred simultaneously, and a few RVO occurred several days after RAO. Although the RAO manifestations are not typical, the radiographic features are both RVO and RAO. Compared with BVRO combined with BRAO, the prognosis of visual acuity in CRAO patients with CRVO is worse.

BACKGROUND:With the application and development of 3D printing technology in medicine,orthopedic internal fixation surgery has become precise and individualized.The equal-scale fracture model obtained by 3D printing technology was simulated and planned before surgery,realizing the leap from traditional 2D images to more vivid and detailed three-dimensional objects.It allows the surgeon to understand the fracture type in advance and rehearse the reduction sequence,so as to realize the individualized implementation of fracture surgery,optimize the surgical process,bring better postoperative recovery and less surgical complications. OBJECTIVE:To compare clinical efficacy of three 3D printed models combined with computerized virtual repositioning technology to assist incision reduction bone plate internal fixation and traditional incision reduction bone plate internal fixation in the treatment of Robinson II B2 clavicle fracture. METHODS:Eighty patients with Robinson II B2 clavicle fracture were randomly divided into trial group(n=40)and control group(n=40).In the trial group,three kinds of 3D printing models(affected clavicle fracture model,computer simulation clavicle fracture reduction model,clavicle mirror model of healthy side)combined with computer virtual reduction technology were used for preoperative in vitro surgery rehearsal.Finally,3D printing was used for clavicle mirror model of healthy side to advance bending and select bone plates for internal fixation.In the control group,open reduction plate internal fixation was applied.The time from admission to surgery,intraoperative blood loss,operation time,frequency of fluoroscopy,number of bends of the bone plate,fracture healing time,complications,and visual analog scale score and Constant score before and after surgery were compared between the two groups. RESULTS AND CONCLUSION:The time from admission to operation in the trial group was greater than that in the control group(P<0.05).Operation time,intraoperative fluoroscopy frequency and bending times of the bone plate in the trial group were lower than those in the control group(P<0.05).The trial group had faster fracture healing and fewer complications(P<0.05).There was no significant difference in intraoperative blood loss between the two groups(P>0.05).Constant score of the two groups had an increasing trend with time(F=613.50,P<0.001),but the difference between the groups was not statistically significant(F=0.08,P=0.78),and there was no interaction between the measurement times and the group assignment(F=0.27,P=0.66).The visual analog scale score decreased with time(F=1 149.55,P<0.001),but there was no significant difference between groups(F=0.02,P=0.88),and there was no interaction between the number of measurements and the group assignment(F=1.02,P=0.36).The results show that the use of 3D printed model combined with computer virtual reduction technology for preoperative rehearsal can shorten the operation time,reduce the number of intraoperative fluoroscopy frequency and the times of bone plate bending,and have the advantages of faster fracture healing,fewer complications,and similar functional recovery to the traditional incision reduction bone plate internal fixation.

Objective:To construct a recombinant bioluminescent bacteriophage (HT7) targeting Escherichia coli, and evaluate its ability to identify Escherichia coli. Methods:Initially, pCRISPR-sg (1-10) and PFN-1000 plasmid strains were constructed by genetic engineering, and the most efficient small guild RNA (sgRNA) were screened by bilayer plate. By the gene editing technique, which comprised homologous recombination and clustered regularly interspaced short palin dromic repeats (CRISPR)-Cas system, the Nanoluc luciferase gene was integrated into the downstream non-coding region of 10A gene of T7 phage, to constructe the bioluminescent phage HT7 successfully. The difference of biological characteristics between HT7 phage and T7 phage was evaluated by plaque assay and liquid amplification assay. In addition, 51 strains of Escherichia coli, 20 strains of Klebsiella pneumoniae, 14 strains of Staphylococcus aureus, 6 strains of Enterococcus faecium, 5 strains of Enterococcus faecalis, 3 strains of Acinetobacter baumannii and 1 strain of Pseudomonas aeruginosa were collected and isolated to evaluate the limit of detection and specificity of HT7 phage. Results:Among the 10 CRISPR-targeted cleavage systems constructed, sgRNA8 exhibited the highest cleavage efficiency, with a cleavage rate of 0.18. After three rounds of recombination screening using the pCas9/pCRISPR/PFN-1000 triple-plasmid system, PCR validation yielded recombinant phage bands at 2 798 bp, indicating the successful construction of the HT7 phage. The recombinant phage showed significant differences in biological characteristics in terms of lysis efficiency ( P<0.001), one-step growth curve ( P=0.001), and infection multiplicity ( P=0.031). Both lysis burst time and log growth node were extended by 10 min, with the optimal infection multiplicity being 0.1. Clinical sample testing identified lysis of 6 strains of Escherichia coli within 4.5 h, while other strains remained unaffected, with detection of pathogenic bacteria below 10 CFU/ml. Conclusions:The developed pCas9/pCRISPR/PFN-1000 triple-plasmid editing system efficiently edits the bacteriophage genome. The constructed HT7 fluorescent bacteriophage enables the detection of Escherichia coli below 10 CFU/ml within 4.5 hours, demonstrating low detection limits and high detection specificity.