Objective　To investigate the level of pertussis antibody in 344 healthy population in Hebei Province in 2023, and to understand the infection status and estimate the potential infection of pertussis. Methods　A total of 344 healthy people of all ages from 7 cities (counties) in Hebei Province in 2023 were stratified by random sampling method. The demographic characteristics, vaccination history and pertussis history of the subjects were collected. Serum IgG antibody against pertussis toxin (PT-IgG) were determined by enzyme-linked immunosorbent assay (ELISA). Results　The geometric mean concentration (GMC) of PT-IgG in 344 healthy people was 5.28 IU/mL, and the antibody positive rate (PT-IgG concentration ≥ 40 IU/mL) was 6.10% (21/344). There was no significant difference in proportion of antibody levels and antibody concentration ≥40 IU/mL between males and females. The top three regions with the highest antibody positive rate were Xinhe County in Xingtai (20.00%), Lianchi District in Baoding (11.43%), and Shijiazhuang (9.37%). There was a significant difference in pertussis antibody levels among different regions (P=0.007), but no significant difference in pertussis antibody concentration ≥40 IU/mL among different regions (P=0.100). The GMC of antibody was the highest in the 1~<3 years old group (11.45 IU/mL), followed by the <1 year old group (8.15 IU/mL). There was a significant difference in the pertussis antibody levels among different age groups (P=0.001). The proportion of antibody concentration ≥40 IU/mL was the highest in the 1~<3 years old group (20.83%), followed by the <1 year old group (12.77%). There was a significant difference in the proportion of antibody concentration ≥40 IU/mL among different age groups (P=0.028). And 303 (88.08%) cases of the 344 healthy people had a history of DTaP , 4.62%, 46.86% and 48.52% of healthy people had completed 1-2 , 3 and 4 doses of DTaP, respectively. Among the healthy people who had completed 1-2 doses of DTaP, there was no significant difference in the level of pertussis antibody among different age groups (P=0.47). Among the healthy people who had completed 3 doses of basic immunization and 4 doses of complete immunization, there was a significant difference in the level of pertussis antibody among different age groups (P=0.04, P=0.01). There was no significant difference in the proportion of PT-IgG concentration ≥40 IU/mL among different age groups and different immunization doses (P=0.72). Conclusion　The overall antibody level and proportion of PT-IgG concentration ≥40 IU/mL in the healthy population of Hebei Province in 2023 were both low, indicating the inadequacy of the protective effect of the current immunization program for children, although vaccinated people could still infect with pertussis disease, we need to further monitoring and optimization of immune strategies indicating.

Objective To investigate the association between the variability of remnant cholesterol inflammatory index(RCII),a novel composite biomarker,and the risk of stroke,in order to provide a theoretical basis for stroke prevention.Methods A prospective cohort study was conducted on 38 659 Kailuan individuals who took annual physical examinations in 2006,2008,and 2010.These subjects were grouped based on the quartiles of RCII variability,which was represented by standard deviation(SD)and average real variability(ARV),and were followed up every 2 years,with the occurrence of stroke(including ischemic and hemorrhagic strokes),death,or the end of follow-up on December 31,2022 as the endpoints.Kaplan-Meier method was used to calculate the cumulative incidence rate of endpoint events across different groups,and log-rank test was used to compare the difference of cumulative incidence of endpoint events in each group.Multivariate Cox proportional hazards regression model was adopted to analyze the association between RCII variability and risk of stroke.Results Among the 38 659 participants,a total of 2 539 strokes occurred during a mean follow-up period of 11.22±2.26 years.After adjusting confounding factors,when the participants were grouped by the quartiles of RCII-SD,the hazard ratio(HR)for stroke was 1.034(95%CI:0.917～1.167,P=0.584),1.146(95%CI:1.018～1.290,P=0.025),and 1.209(95%CI:1.066～1.370,P=0.003),respectively in the Q2,Q3,and Q4 groups,when compared with the Q1 group(Ptrend<0.05).When they were grouped by the quartiles of RCII-ARV,the HR for stroke was 1.008(95%CI:0.894～1.136,P=0.901),1.109(95%CI:0.986～1.248,P=0.085),and 1.152(95%CI:1.018～1.303,P=0.025),respectively,in the Q2,Q3,and Q4 groups,when compared with the Q1 group.Furthermore,both sensitivity and stratified analyses yielded similar results.Conclusion RCII variability is significantly associated with stroke,and the risk of stroke is gradually increasing with increment of the variability.Countermeasures Relevant authorities can focus on reducing RCII variability as a central objective by establishing regular monitoring mechanism,strengthening lifestyle interventions,and standardizing dietary,exercise,and weight management in order to suppress the index fluctuations.The principle of stable lipid-lowering in medication and optimization of therapeutic regimens with stable efficacy should be emphasized to prevent the risk of additional vascular damage.

Objective:To report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical Gram-negative bacteria isolates from bloodstream infections in China in 2022.Methods:The clinical isolates of Gram-negative bacteria from blood cultures in member hospitals of national bloodstream infection Bacterial Resistant Investigation Collaborative System（BRICS）were collected during January 2022 to December 2022. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute（CLSI）. WHONET 5.6 and SPSS 25.0 software were used to analyze the data.Results:During the study period，9 035 strains of Gram-negative bacteria were collected from 51 hospitals，of which 7 895（87.4%）were Enterobacteriaceae and 1 140（12.6%）were non-fermenting bacteria. The top 5 bacterial species were Escherichia coli（ n=4 510，49.9%）， Klebsiella pneumoniae（ n=2 340，25.9%）， Pseudomonas aeruginosa（ n=534，5.9%）， Acinetobacter baumannii complex（ n=405，4.5%）and Enterobacter cloacae（ n=327，3.6%）. The ESBLs-producing rates in Escherichia coli， Klebsiella pneumoniae and Proteus spp. were 47.1%（2 095/4 452），21.0%（427/2 033）and 41.1%（58/141），respectively. The prevalence of carbapenem-resistant Escherichia coli（CREC）and carbapenem-resistant Klebsiella pneumoniae（CRKP）were 1.3%（58/4 510）and 13.1%（307/2 340）；62.1%（36/58）and 9.8%（30/307）of CREC and CRKP were resistant to ceftazidime/avibactam combination，respectively. The prevalence of carbapenem-resistant Acinetobacter baumannii（CRAB）complex was 59.5%（241/405），while less than 5% of Acinetobacter baumannii complex was resistant to tigecycline and polymyxin B. The prevalence of carbapenem-resistant Pseudomonas aeruginosa（CRPA）was 18.4%（98/534）. There were differences in the composition ratio of Gram-negative bacteria in bloodstream infections and the prevalence of main Gram-negative bacteria resistance among different regions，with statistically significant differences in the prevalence of CRKP and CRPA（ χ2=20.489 and 20.252， P<0.001）. The prevalence of CREC，CRKP，CRPA，CRAB，ESBLs-producing Escherichia coli and Klebsiella pneumoniae were higher in provinicial hospitals than those in municipal hospitals（ χ2=11.953，81.183，10.404，5.915，12.415 and 6.459， P<0.01 or <0.05），while the prevalence of CRPA was higher in economically developed regions（per capita GDP ≥ 92 059 Yuan）than that in economically less-developed regions（per capita GDP <92 059 Yuan）（ χ2=6.240， P=0.012）. Conclusions:The proportion of Gram-negative bacteria in bloodstream infections shows an increasing trend，and Escherichia coli is ranked in the top，while the trend of CRKP decreases continuously with time. Decreasing trends are noted in ESBLs-producing Escherichia coli and Klebsiella pneumoniae. Low prevalence of carbapenem resistance in Escherichia coli and high prevalence in CRAB complex have been observed. The composition ratio and antibacterial spectrum of bloodstream infections in different regions of China are slightly different，and the proportion of main drug resistant bacteria in provincial hospitals is higher than those in municipal hospitals.

Objective:To explore the risk factors of postpartum hemorrhage in parturients undergoing vaginal delivery with a second child and establish a risk prediction model.Methods:Using the convenient sampling method, a total of 2 500 parturients undergoing vaginal delivery with a second child who underwent regular prenatal examinations at Peking University Third Hospital from July 2019 to March 2023 were selected as the research objects. According to the amount of blood loss, parturients with blood loss greater than or equal to 500 ml within 24 hours after delivery were selected as the case group ( n=278), while parturients with blood loss less than 500 ml within 24 hours after delivery in the same period were selected as the control group ( n=2 222). Univariate analysis and binomial Logistic regression were used to analyze the influencing factors of postpartum hemorrhage in parturients with vaginal delivery with a second child. Based on the selected risk factors, a nomogram prediction model was established using R software, and the consistency of the model was tested. Results:The incidence of postpartum hemorrhage in 2 500 parturients undergoing vaginal delivery with a second child was 11.12% (278/2 500). Binomial Logistic regression analysis showed that in in vitro fertilization-embryo transfer, pre-delivery body mass index, lateral perineal incision, neonatal weight, placenta previa, placenta implantation and manual extraction of placenta were the influencing factors for postpartum hemorrhage in parturients undergoing vaginal delivery with a second child ( P<0.05). According to the influencing factors, a nomogram model was established to predict the probability of postpartum hemorrhage in women who gave birth to a second child. The C- index of the prediction model was 0.706, the area under the receiver operating characteristic curve was 0.706, and the χ 2 value of the Hosmer-Lemeshow goodness-of-fit test was 7.720 ( P=0.461) . Conclusions:In vitro fertilization embryo transfer, pre-delivery body mass index, perineal lateral resection, neonatal weight, placenta previa, placental implantation and manual extraction of placenta are risk factors for postpartum hemorrhage in parturients undergoing vaginal delivery for a second child. The prediction model constructed based on risk factors has certain accuracy and clinical value for predicting postpartum hemorrhage in parturients with vaginal delivery of a second child.

Objective:To report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical Gram-positive bacteria isolates from bloodstream infections in China in 2022.Methods:The clinical isolates of Gram-positive bacteria from blood cultures in member hospitals of National Bloodstream Infection Bacterial Resistant Investigation Collaborative System（BRICS）were collected during January 2022 to December 2022. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute（CLSI）. WHONET 5.6 and SPSS 25.0 software were used to analyze the data.Results:A total of 3 163 strains of Gram-positive pathogens were collected from 51 member units，and the top five bacteria were Staphylococcus aureus（ n=1 147，36.3%），coagulase-negative Staphylococci（ n=928，29.3%）， Enterococcus faecalis（ n=369，11.7%）， Enterococcus faecium（ n=296，9.4%）and alpha-hemolyticus Streptococci（ n=192，6.1%）. The detection rates of methicillin-resistant Staphylococcus aureus（MRSA）and methicillin-resistant coagulase-negative Staphylococci（MRCNS）were 26.4%（303/1 147）and 66.7%（619/928），respectively. No glycopeptide and daptomycin-resistant Staphylococci were detected. The sensitivity rates of Staphylococcus aureus to cefpirome，rifampin，compound sulfamethoxazole，linezolid，minocycline and tigecycline were all >95.0%. Enterococcus faecium was more prevalent than Enterococcus faecalis. The resistance rates of Enterococcus faecium to vancomycin and teicoplanin were both 0.5%（2/369），and no vancomycin-resistant Enterococcus faecium was detected. The detection rate of MRSA in southern China was significantly lower than that in other regions（ χ2=14.578， P=0.002），while the detection rate of MRCNS in northern China was significantly higher than that in other regions（ χ2=15.195， P=0.002）. The detection rates of MRSA and MRCNS in provincial hospitals were higher than those in municipal hospitals（ χ2=13.519 and 12.136， P<0.001）. The detection rates of MRSA and MRCNS in economically more advanced regions（per capita GDP≥92 059 Yuan in 2022）were higher than those in economically less advanced regions（per capita GDP<92 059 Yuan）（ χ2=9.969 and 7.606， P=0.002和0.006）. Conclusions:Among the Gram-positive pathogens causing bloodstream infections in China， Staphylococci is the most common while the MRSA incidence decreases continuously with time；the detection rate of Enterococcus faecium exceeds that of Enterococcus faecalis. The overall prevalence of vancomycin-resistant Enterococci is still at a low level. The composition ratio of Gram-positive pathogens and resistant profiles varies slightly across regions of China，with the prevalence of MRSA and MRCNS being more pronounced in provincial hospitals and areas with a per capita GDP≥92 059 yuan.

Objective:To investigate the carriage status of Neisseria meningitidis ( Nm) among the healthy population in Hebei Province for the prevention and control of meningitis. Methods:From 2015 to 2022, throat swabs were collected from health people, which were selected by cluster random sampling in 11 cities of Hebei.The positive rate of Nm was detected by bacterial culture. The serogroups of isolated strains were identified.The laboratory detection results of Nm strains, combined with epidemiological survey data, were synthetically analyzed. Results:A total of 20 245 people were investigated; 249 strains of Nm were isolated; the overall Nm carriage rate was 1.23%. The carriage rate was significantly higher in men than in women(χ 2=28.831, P<0.05). The positive rates of Nm in different age groups were significantly different(χ 2=428.018, P<0.05), with the highest rates in the 15-19 year-old group(4.90%, 149/3 042). The positive rates of Nm were significantly different in different regions(χ 2=177.512, P<0.05), with the highest positive rate of Nm in Xingtai, Shijiazhuang, Chengde and Baoding city in sequence. Among the isolated Nm strains, ungroupable serogroups, serogroup B, serogroup C, and serogroup W accounted for 71.49%(178/249), 13.65%(34/249), 6.83%(17/249) and 4.42%(11/249), respectively. Conclusions:The carriage rate of Nm among healthy population is generally low in Hebei Province. It is recommended to continue to strengthen monitoring, pay attention to the changes and distribution characteristics of Nm, and formulate scientific and targeted prevention and control measures of meningococcal disease.

Background: Immunochemotherapy has demonstrated a promising efficacy for a variety of B-cell lymphoma but has limited efficacy for Epstein–Barr virus-positive (EBV +) diffuse large B-cell lymphoma (DLBCL) that is refractory or relapsed to conventional chemotherapy regimens. Considering higher programmed death-ligand 1 (PD-L1) expres‑ sion in the subset of patients with DLBCL with positive EBV, we speculated that PD-1 inhibitors plus chemotherapy may be an alternative regimen in patients with refractory/relapsed EBV + DLBCL. Methods: This retrospective study included six adult patients diagnosed with refractory EBV + DLBCL resistant to first-line immunochemotherapy regimens (R-CHOP). These patients received PD-1 inhibitors plus chemotherapy as second-line treatment. Results: The final analysis included six patients (four men and two women (median age, 50 years; range, 39–83 years)). Four patients were diagnosed with Epstein–Barr virus (EBV) + DLBCL, and two had DLBCL associated with chronic inflammation. Over a median follow-up of 20 months (range, 2–31 months), the objective response rate was 83% (5/6) and the complete remission rate was 67% (4/6). No severe immune-related adverse reactions occurred, and only a mild rash was reported, which did not necessitate the discontinuation of therapy. Conclusion The combination of PD-1 inhibitors and chemotherapy offers promising results as a second-line treat‑ ment for patients with refractory EBV + DLBCL that is resistant to first-line immunochemotherapy regimens. These preliminary findings warrant further investigation in larger clinical trials to validate the efficacy and safety of this therapeutic approach.

Abstract: Objective To evaluate the impact of meningococcal vaccine immunization on the incidence of meningococcal meningitis, aiming to refine the local immunization strategies and programs. Methods Data on the reported incidence of meningococcal meningitis in Hebei province for 1970-2023 were collected, and interrupted time-series( ITS) analysis was used to quantitatively analyze the levels and slope change of the incidence of meningococcal meningitis before and after vaccine immunization and before and after inclusion in the Expanded Program on Immunization (EPI). Results The annual average reported incidences of meningococcal meningitis in Hebei province before vaccination (1970-1979), before (1980-2007) and after (2008-2023) the inclusion of the vaccine in the EPI were respectively 20.79 per 100 000, 1.66 per 100 000, and 0.018 per 100 000. The interrupted time-series analysis from 1970 to 2023 showed an initial meningitis incidence rate of 24.12 per 100 000 (t=9.86, P<0.05), with an average annual decrease of 1.07 per 100 000 (t=-2.42, P<0.05). After the introduction of the meningococcal vaccine in 1980, the incidence of meningococcal meningitis decreased quickly with an annual average decline of 18.39 per 100 000, showing a significant short-term intervention effect (t=-2.70, P<0.05); however, the rate of decrease slowed over the long term to 0.13 per 100 000, with the long-term intervention effect not being significant (P>0.05). And the incidence was significantly increased due to the outbreak (t=7.80, P<0.05). From 1980 to 2023, the initial level of incidence was 5.13 per 100 000 (t=8.70, P<0.05), and decreased by 0.23/100 000 per year on average (t=-6.42, P<0.05). After the inclusion of the vaccine in the EPI in 2008, the rate of decrease further slowed down to an average of 0.008 per 100,000 per year, with the long-term intervention effect being significant (t=2.50, P<0.05); the impact of epidemic outbreaks on incidence during this period was not statistically significant (P>0.05). Conclusions Meningococcal meningitis vaccination has led to a general downward trend in the incidence of meningitis in Hebei Province, and has flattened the trend of increased incidence caused by outbreaks. Therefore, long-term maintenance in immunization programs on the meningococcal meningitis is necessary. In addition, it is important to strengthen the monitoring of the distribution of epidemic serogroups in patients and healthy carriers, and to adjust immunization strategies timely based on changes in bacterial populations, selecting and promoting vaccines accordingly for the prevalent strains.

Background: Immunochemotherapy has demonstrated a promising efficacy for a variety of B-cell lymphoma but has limited efficacy for Epstein–Barr virus-positive (EBV +) diffuse large B-cell lymphoma (DLBCL) that is refractory or relapsed to conventional chemotherapy regimens. Considering higher programmed death-ligand 1 (PD-L1) expres‑ sion in the subset of patients with DLBCL with positive EBV, we speculated that PD-1 inhibitors plus chemotherapy may be an alternative regimen in patients with refractory/relapsed EBV + DLBCL. Methods: This retrospective study included six adult patients diagnosed with refractory EBV + DLBCL resistant to first-line immunochemotherapy regimens (R-CHOP). These patients received PD-1 inhibitors plus chemotherapy as second-line treatment. Results: The final analysis included six patients (four men and two women (median age, 50 years; range, 39–83 years)). Four patients were diagnosed with Epstein–Barr virus (EBV) + DLBCL, and two had DLBCL associated with chronic inflammation. Over a median follow-up of 20 months (range, 2–31 months), the objective response rate was 83% (5/6) and the complete remission rate was 67% (4/6). No severe immune-related adverse reactions occurred, and only a mild rash was reported, which did not necessitate the discontinuation of therapy. Conclusion The combination of PD-1 inhibitors and chemotherapy offers promising results as a second-line treat‑ ment for patients with refractory EBV + DLBCL that is resistant to first-line immunochemotherapy regimens. These preliminary findings warrant further investigation in larger clinical trials to validate the efficacy and safety of this therapeutic approach.

Background: Immunochemotherapy has demonstrated a promising efficacy for a variety of B-cell lymphoma but has limited efficacy for Epstein–Barr virus-positive (EBV +) diffuse large B-cell lymphoma (DLBCL) that is refractory or relapsed to conventional chemotherapy regimens. Considering higher programmed death-ligand 1 (PD-L1) expres‑ sion in the subset of patients with DLBCL with positive EBV, we speculated that PD-1 inhibitors plus chemotherapy may be an alternative regimen in patients with refractory/relapsed EBV + DLBCL. Methods: This retrospective study included six adult patients diagnosed with refractory EBV + DLBCL resistant to first-line immunochemotherapy regimens (R-CHOP). These patients received PD-1 inhibitors plus chemotherapy as second-line treatment. Results: The final analysis included six patients (four men and two women (median age, 50 years; range, 39–83 years)). Four patients were diagnosed with Epstein–Barr virus (EBV) + DLBCL, and two had DLBCL associated with chronic inflammation. Over a median follow-up of 20 months (range, 2–31 months), the objective response rate was 83% (5/6) and the complete remission rate was 67% (4/6). No severe immune-related adverse reactions occurred, and only a mild rash was reported, which did not necessitate the discontinuation of therapy. Conclusion The combination of PD-1 inhibitors and chemotherapy offers promising results as a second-line treat‑ ment for patients with refractory EBV + DLBCL that is resistant to first-line immunochemotherapy regimens. These preliminary findings warrant further investigation in larger clinical trials to validate the efficacy and safety of this therapeutic approach.