Objective To gain insights into the biological characteristics of different populations of Culex tritaeniorhynchus within and around the Yellow Sea wetland from the perspective of the occurrence of resistance, we investigated the levels of resistance to deltamethrin and kdr gene mutation in the wetland and its peripheral areas. Methods Specimens were collected from Cx. tritaeniorhynchus populations at two monitoring sites in the Rare Bird National Nature Reserve and Tiaozi Ni Wetland Scenic Area, and also from two populations in Yancheng City and the Liuhe District of Nanjing, and the resistance of these mosquitoes to deltamethrin was determined using the CDC biotest bottle method. For each concentration of deltamethrin assessed, a random subset of exposed specimens was selected for amplification of the kdr gene fragment, followed by Sanger sequencing to identify and analyze resistance-associated mutations. Results The LC50 levels of deltamethrin among mosquitoes from the four populations in Luhe, Yancheng, the Rare Bird National Nature Reserve and the Tiaozi Ni Wetland Scenic Area were 2.048 5, 7.798 2, 3.473 3, and 17.695 5 mg/mL, respectively, with corresponding concentrations of deltamethrin ranging from 0.005 to 5.000,0.050 to 50.000,0.050 to 25.000 and 0.050 to 50.000 mg/mL, respectively. Furthermore, the ranges of the KT50 values were 11.76-107.43, 67.05-216.30,29.77-107.43 and 28.40-329.51 min; the 1-h knockdown rates were 34.58%-99.15%, 9.52%-43.80%, 55.09%-73.01%, and 10.09%-68.07%; and the 24-h mortality rates were 12.15%-67.52%,9.52%-79.56%,13.17%-82.21%, and 11.01%-78.99%, respectively. With respect to kdr gene mutation, we assayed a total of 63,70,59, and 57 mosquitoes for the four populations, for which we detected L1014F mutation frequencies of 14.29%, 35.00%, 20.34%, and 31.58%, respectively, with a majority of these mutations being heterozygous for resistance. In addition, five adult mosquitoes were identified has having synonymous mutations at site 1011[i. e. , AAT(asparagine)mutation to AAC(asparagine)]. Conclusions Our findings revealed the clear resistance of Cx. tritaeniorhynchus to deltamethrin in the Yancheng region of the Yellow Sea wetland, and the resistance phenotype and kdr frequency of Cx. tritaeniorhynchus in the wetland environment were comparable to those of Cx. tritaeniorhynchus in the wetland environment, thereby indicating that the resistance of different populations of Cx. tritaeniorhynchus was homogeneous under the pressure of different insecticide selection within and around the wetland. However, the underlying mechanisms need to be further studied.

Objective To compare the application effects of plankton multiplex polymerase chain reac-tion-capillary electrophoresis(PCR-CE),SYBR Green Ⅰ real-time quantitative PCR(qPCR)and microwave digestion-vacuum filtration-automated scanning electron microscopy(MD-VF-Auto SEM)in the diagnosis of drowning.Methods Lung,liver and kidney tissues from 212 drowned corpses and 30 non-drowned corpses were examined respectively by the three drowning-related plankton testing methods,and the detection rates of plankton in each tissue by three methods were compared.Results In drowned corpses,the total detection rates of PCR-CE,qPCR,and MD-VF-Auto SEM were 93.9%,96.2%,and 95.3%,respectively,with no statistically significant difference(P>0.05).The detection rate of lung tissue by MD-VF-Auto SEM(100%)was higher than those of PCR-CE and qPCR(P<0.05),and there was no significant difference in the detection rates of the three methods in liver or kidney tissues(P>0.05).In non-drowning corpses,a small number of diatoms(less than 10 cells/10 g)were detected by MD-VF-Auto SEM method,only in liver and kidney tissues,while the other two methods yielded negative results for all tissues.Conclusion All three methods have good efficacy in the examination of drowned corpses.The MD-VF-Auto SEM method directly observes diatom morpho-logical characteristics through scanning electron microscopy,and the qualitative and quantitative analy-ses are intuitive and accurate.It has great advantages in the examination of difficult degradation samples.The PCR-CE method and qPCR method have a low sample demand(0.5 g),are easy to operate and have short detection time(4-7 h).They are easy to be applied in the grassroots depart-ments and are suitable for the rapid determination of drowned corpses in routin cases.The combina-tion of the two DNA methods with the MD-VF-Auto SEM method can increase the detection rate of plankton,ensuring the reliability of examination results.This combined use is of significant importance in the application of drowning diagnosis.

Objective To examine the changing prevalence and antimicrobial resistance profiles of Burkholderia cepacia in 52 hospitals across China from 2015 to 2021.Methods A total of 9 261 strains of B.cepacia were collected from 52 hospitals between January 1,2015 and December 31,2021.Antimicrobial susceptibility of the strains was tested using Kirby-Bauer method or automated antimicrobial susceptibility testing systems according to a unified protocol.The results were interpreted according to the breakpoints released in the Clinical & Laboratory Standards Institute(CLSI)guidelines(2023 edition).Results A total of 9 261 strains of B.cepacia were isolated from all age groups,especially elderly patients.The proportion was 11.1％(1 032 strains)in children,significantly lower than the proportion in adults.About half(46.5％,4 310/9 261)of the strains were isolated from patients at least 60 years old and 42.3％(3 919/9 261)of the strains were isolated from young adults.Most isolates(71.1％)were isolated from sputum and respiratory secretions,followed by urine(10.7％)and blood samples(8.1％).B.cepacia isolates were highly susceptible to the five antimicrobial agents recommended in the CLSI M100 document(33rd edition,2023).B.cepacia isolates showed relatively higher resistance rates to meropenem and levofloxacin.However,the resistance rates to ceftazidime,trimethoprim-sulfamethoxazole,and minocycline remained below 8.1％.The percentage of B.cepacia strains resistant to levofloxacin was the highest compared to other antibiotics in any of the three age groups(from 12.4％in the patients＜18 years old to 20.6％in the patients aged 60 years or older).Conclusions B.cepacia is one of the clinically important non-fermenting gram-negative bacteria.Accurate and timely reporting of antimicrobial susceptibility test results and ongoing antimicrobial resistance surveillance are helpful for rational prescription of antimicrobial agents and proper prevention and control of nosocomial infections.

Objective:To compare the efficacy of different doses of tranexamic acid (TXA) for traumatic hemorrhagic shock (THS) in the early phase of trauma following acute exposure to high altitude in rabbits.Methods:Twenty-five healthy male New Zealand rabbits were randomly divided into plain control group ( n=5) and acute high-altitude THS group ( n=20) according to the random number table method. The plain control group did not undergo THS modeling throughout the experiment while the acute high-altitude THS group was raised in a hypoxia simulation chamber with a volume fraction of 10% for 3 days to establish the THS model. Based on the different doses of TXA administered intravenously at 30 minutes after THS modeling, the acute high-altitude THS group was further divided into four subgroups: acute high-altitude THS+0 mg/kg TXA subgroup, acute high-altitude THS+45 mg/kg TXA subgroup, acute high-altitude THS+90 mg/kg TXA subgroup and acute high-altitude THS+135 mg/kg TXA subgroup, with 5 rabbits in each. The vital signs [mean arterial pressure (MAP), heart rate, rectal temperature] and blood cell counts [red blood cell count (RBC), platelet count (PLT)], 4 coagulation parameters [fibrinogen (FIB), D-dimer, activated partial thromboplastin time (APTT), prothrombin time (PT)], thromboelastography [clotting reaction time (R value), clot formation time (K value), maximum amplitude (MA value)], syndecan-1, inflammatory factors [interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α)], and plasminogen activator inhibitor-1 (PAI-1) were recorded before blood loss, at 30 minutes and 120 minutes after blood loss. At 6 hours after THS, the lungs, terminal ileum, and kidneys of the rabbits were collected to observe tissue damage, and the wet/dry weight ratio (W/D) and total water content (TLW) of the lung tissue were measured. Results:(1) Vital signs: Before blood loss, there were no significant differences in MAP, heart rate, or rectal temperature between the acute high-altitude THS subgroups and the plain control group ( P>0.05). At 30 minutes and 120 minutes after blood loss, the acute high-altitude THS subgroups exhibited significantly lower MAP, heart rate, and rectal temperature compared to those in the plain control group ( P<0.05). No significant differences were observed in MAP, heart rate or rectal temperature among the acute high-altitude THS subgroups at any time point ( P>0.05). In the acute high-altitude THS subgroups, MAP, heart rate and rectal temperature were significantly decreased at 30 minutes and 120 minutes after blood loss compared to those before blood loss ( P<0.05); At 120 minutes after blood loss, these parameters were further significantly decreased compared to those at 30 minutes after blood loss ( P<0.05). (2) Blood cell counts: Before blood loss, the RBC count was significantly higher in the acute high-altitude THS subgroups compared to that in the plain control group ( P<0.05), while the PLT was significantly lower ( P<0.05). At 30 minutes after blood loss, there was no significant difference in RBC count between the acute high-altitude THS subgroups and the plain control group ( P>0.05), but the PLT remained significantly lower in the acute high-altitude THS subgroups ( P<0.05). At 120 minutes after blood loss, the RBC count was significantly lower in the acute high-altitude THS subgroups compared to that in the plain control group ( P<0.05), with no significant differences among the acute high-altitude THS subgroups ( P>0.05). The PLT count was significantly lower in the acute high-altitude THS+0 mg/kg TXA subgroup compared to the other subgroups ( P<0.05). The PLT count in the acute high-altitude THS+45 mg/kg TXA subgroup was significantly lower than those in the acute high-altitude THS+90 mg/kg TXA and acute high-altitude THS+135 mg/kg TXA subgroups ( P<0.05), with no significant differences between the latter two subgroups ( P>0.05). (3) Four Coagulation parameters: Before blood loss, D-dimer level was significantly higher in the acute high-altitude THS subgroups compared to that in the plain control group ( P<0.05), while no significant difference was observed in FIB ( P>0.05). APTT and PT were significantly shortened in the acute high-altitude THS subgroups ( P<0.05). At 30 minutes after blood loss, D-dimer level remained significantly higher in the acute high-altitude THS subgroups compared to that in the plain control group ( P<0.05), while FIB was significantly lower ( P<0.05), with significant increase of APTT and PT compared to those before blood loss ( P<0.05). At 120 minutes after blood loss, the acute high-altitude THS+0 mg/kg TXA subgroup exhibited significantly higher D-dimer level compared to the other subgroups ( P<0.05), with significantly lower FIB and higher APTT and PT ( P<0.05). The acute high-altitude THS+45 mg/kg TXA subgroup also showed significantly higher D-dimer level compared to those in the acute high-altitude THS+90 mg/kg TXA and acute high-altitude THS+135 mg/kg TXA subgroups ( P<0.05), with significantly lower FIB and increased APTT and PT ( P<0.05). No significant differences were observed in D-dimer, FIB, APTT or PT between the acute high-altitude THS+90 mg/kg TXA and acute high-altitude THS+135 mg/kg TXA subgroups ( P>0.05). (4) Thromboelastography parameters: Before blood loss, the R value was significantly shorter in the acute high-altitude THS subgroups compared to that in the plain control group ( P<0.05), while no significant differences were observed in K value or MA value ( P>0.05). At 30 minutes after blood loss, both R value and K value were significantly shorter in the acute high-altitude THS subgroups compared to those in the plain control group ( P<0.05), with no significant differences in MA value ( P>0.05). At 120 minutes after blood loss, the acute high-altitude THS+0 mg/kg TXA subgroup exhibited significantly increased R value and K value compared to those in the other subgroups ( P<0.05), while MA value was significantly decreased ( P<0.05). The remaining acute high-altitude THS subgroups showed significant decrease of R value and K value compared to those in the plain control group ( P<0.05), while MA value was significantly lower ( P<0.05). The acute high-altitude THS+45 mg/kg TXA subgroup exhibited significantly lower R value and K value compared to those in the acute high-altitude THS+90 mg/kg TXA and acute high-altitude THS+135 mg/kg TXA subgroups ( P<0.05), with no significant differences in R value, K value and MA value between the later two groups ( P<0.05). (5) Changes in Syndecan-1, inflammatory factors and PAI-1: Before blood loss, syndecan-1 was significantly higher in the acute high-altitude THS subgroups compared to that in the plain control group ( P<0.05), while no significant differences were observed in IL-6, TNF-α, or PAI-1 ( P>0.05). At 30 minutes after blood loss, syndecan-1, IL-6, TNF-α, and PAI-1 were significantly higher in the acute high-altitude THS subgroups compared to those in the plain control group ( P<0.05). At 120 minutes after blood loss, syndecan-1, IL-6, TNF-α, and PAI-1 were significantly higher in the acute high-altitude THS subgroups compared to those in the plain control group ( P<0.05). Among them, the acute high-altitude THS+0 mg/kg TXA group exhibited significantly higher levels of syndecan-1, IL-6, TNF-α, and PAI-1 compared to the other acute high-altitude THS subgroups ( P<0.05). The acute high-altitude THS+45 mg/kg TXA subgroup had significantly higher syndecan-1, IL-6, and TNF-α compared to those in the acute high-altitude THS+90 mg/kg TXA and acute high-altitude THS+135 mg/kg TXA subgroups ( P<0.05), with no significant difference in PAI-1 ( P>0.05). No significant differences were observed in syndecan-1, IL-6, TNF-α or PAI-1 between the acute high-altitude THS+90 mg/kg TXA and acute high-altitude THS+135 mg/kg TXA subgroups ( P>0.05). (6) Tissue injury: At 6 hours after THS, acute high-altitude THS+0 mg/kg TXA group exhibited significant interstitial thickening of the lung with extensive inflammatory cell infiltration, localized loss of intestinal brush border accompanied by cellular disruption, and marked structural disruption of renal corpuscles with focal cellular injury and necrosis. At 6 hours after THS, the acute high-altitude THS+0 mg/kg TXA subgroup exhibited significantly higher lung injury scores, Chiu′s intestinal injury scores, and kidney injury scores compared to those of the other subgroups ( P<0.05). No significant differences were observed in the tissue injury scores of the lungs, intestines and kidneys among the other subgroups ( P>0.05). The acute high-altitude THS+0 mg/kg TXA subgroup also had significantly higher lung W/D and TLW compared to those in the other subgroups ( P<0.05). At 6 hours after THS, the acute high-altitude THS+45 mg/kg TXA group exhibited significantly higher W/D and TLW of the lung tissues compared to those in the acute high-altitude THS+90 mg/kg TXA and acute high-altitude THS+135 mg/kg TXA groups ( P<0.05), with no significant differences between the latter two subgroups ( P>0.05). Conclusions:At 3 days after acute exposure to high altitude, rabbits show a hypercoagulable state of the blood, accompanied by endothelial barrier dysfunction. At 30 minutes after the induction of acute high-altitude THS, a single slow intravenous bolus injection of TXA at doses of 90 mg/kg and 135 mg/kg is more effective in improving coagulation and fibrinolysis function, inflammatory response, endothelial injury, and reduced the risk of pulmonary edema than that at a dose of 45 mg/kg.

This study aims to analyze the screening results and epidemiological characteristics of prostate cancer (PCa) among elderly males in the rural areas of Songjiang, Shanghai City, through the implementation of a preliminary prostate-specific antigen (PSA) screening based on a community-linkage model, and to explore an effective screening approach. A retrospective observational study design was employed to collect data from residents who underwent PSA screening at Songjiang Hospital affiliated to Shanghai Jiao Tong University School of Medicine, in collaboration with multiple community health service centers in Songjiang District, Shanghai City, between June 2022 and June 2024, through free clinics and annual health examinations. Prostate biopsy was recommended for individuals with total PSA (tPSA) levels >10 ng/ml and those with 4 ng/ml≤tPSA≤10 ng/ml and abnormal free-to-total PSA (f/tPSA) ratios. Clinical characteristics of detected PCa patients were analyzed. Follow-up was conducted through phone calls and home visits by family doctors, coupled with enhanced health education. The results indicated that a total of 17 198 residents participated in the screening, among which 2 234 (12.99%) had tPSA levels between 4 ng/ml and 10 ng/ml, and 257 (1.49%) had tPSA levels >10 ng/ml. Ultimately, 417 residents underwent prostate biopsy, with 171 being diagnosed with PCa, yielding a positive biopsy rate of 41.00% and a PCa detection rate of 0.99%. The predominant pathological subtype among PCa patients was adenocarcinoma (168 cases, 98.24%). Of the 146 PCa patients who received treatment, the majority were classified as intermediate or high-risk (124 cases, 84.93%). Furthermore, with the optimization of the screening model, there was a significant increase in the proportion of subsequent outpatient visits. In conclusion, the community-linkage-based PSA screening model demonstrated high effectiveness in screening for PCa among elderly males in the rural areas of Songjiang, Shanghai City. Epidemiological findings revealed that PCa patients in this region are primarily composed of intermediate and high-risk groups, highlighting the need for intensified early screening and health education.

This research aims to construct a stable epithelial cell senescence model for screening and e-valuation of senolytics.We explored the optimal conditions for doxorubicin-induced senescence of non-transformed epithelial cells MCF 10A,including the optimal induction concentration,the optimal inter-vention time,and the optimal senescence duration,and confirmed the feasibility of MCF 10A as an epi-thelial senescence model by multiple ways.The optimal condition for Doxorubicin-induced senescence of MCF 10A cells was treatment with 0.6 μmol/L Doxorubicin for 16 h to achieve the best senescence state on the 8th day.Under the optimal induction conditions,the positive rate of senescence-associated β-gal-actosidase(SA-β-gal)staining in the treated group reached 97％.At the same time,biochemical results of detecting the expression of mRNA,proteins,and immunofluorescence demonstrated that the expression levels of senescence-associated secretory phenotype(SASP),p16,p21 and p53 in the treated group were significantly higher than those in the control cells,and Lamin B1 was significantly decreased(P＜0.001),which were consistent with the specific characteristics of senescence.In summary,an epithelial senescence model was successfully induced in MCF 10A cells by Doxorubicin in this study,which will promote the screening of senolytics for senescent epithelial cells.

This study aims to analyze the screening results and epidemiological characteristics of prostate cancer (PCa) among elderly males in the rural areas of Songjiang, Shanghai City, through the implementation of a preliminary prostate-specific antigen (PSA) screening based on a community-linkage model, and to explore an effective screening approach. A retrospective observational study design was employed to collect data from residents who underwent PSA screening at Songjiang Hospital affiliated to Shanghai Jiao Tong University School of Medicine, in collaboration with multiple community health service centers in Songjiang District, Shanghai City, between June 2022 and June 2024, through free clinics and annual health examinations. Prostate biopsy was recommended for individuals with total PSA (tPSA) levels >10 ng/ml and those with 4 ng/ml≤tPSA≤10 ng/ml and abnormal free-to-total PSA (f/tPSA) ratios. Clinical characteristics of detected PCa patients were analyzed. Follow-up was conducted through phone calls and home visits by family doctors, coupled with enhanced health education. The results indicated that a total of 17 198 residents participated in the screening, among which 2 234 (12.99%) had tPSA levels between 4 ng/ml and 10 ng/ml, and 257 (1.49%) had tPSA levels >10 ng/ml. Ultimately, 417 residents underwent prostate biopsy, with 171 being diagnosed with PCa, yielding a positive biopsy rate of 41.00% and a PCa detection rate of 0.99%. The predominant pathological subtype among PCa patients was adenocarcinoma (168 cases, 98.24%). Of the 146 PCa patients who received treatment, the majority were classified as intermediate or high-risk (124 cases, 84.93%). Furthermore, with the optimization of the screening model, there was a significant increase in the proportion of subsequent outpatient visits. In conclusion, the community-linkage-based PSA screening model demonstrated high effectiveness in screening for PCa among elderly males in the rural areas of Songjiang, Shanghai City. Epidemiological findings revealed that PCa patients in this region are primarily composed of intermediate and high-risk groups, highlighting the need for intensified early screening and health education.

AIM To investigate the protective effects of Shuangyi Qushi Tongluo Capsules(Shuangyi Capsules)on Dexamethasone(Dex)induced osteoporosis in mice.METHODS The C57BL/6J mice were randomly divided into the control group,the model group,the Xianling Gubao Capsules group(1.5 g/kg),and the low-dose,moderate-dose,and high-dose Shuangyi Capsules groups(0.6,1.2,and 2.4 g/kg).The mouse model of osteoporosis was induced by 8-week intraperitoneal injection of Dex sodium phosphate injection(5 mg/kg).The mice had their femur osteogenesis observed with hematoxylin and eosin(HE)staining and tartrate-resistant acid phosphatase(TRAP)staining;their serum alkaline phosphatase(ALP)and osteocalcin(BGP)activities detected by ELISA;their femoral mRNA expressions of Col-Ⅰ,OCN,and OPN detected by RT-qPCR;and their femoral protein expressions of OPG and RANKL detected by Western blot.Upon the MC3T3-E1 cells exposed to Dex and Shuangyi Capsules,their viability was evaluated by CCK-8 assay;their mineralization determined by alkaline phosphatase staining and alizarin red staining(ARS);and their intracellular ROS level detected using DCFH-DA probe.RESULTS Compared with the model group,Shuangyi Capsules groups demonstrated improved fracture of femoral trabeculae and reduced number of osteoclasts;increased serum ALP and BGP activities(P＜0.05,P＜0.01);increased femoral expressions of Col-Ⅰ mRNA and OPG protein(P＜0.05,P＜0.01);and decreased RANKL protein expression(P＜0.05).Compared with the MC3T3-E1 cells stimulated by Dex,those underwent further treatment of Shuangyi Capsules demonstrated increased cell viability and ALP activity(P＜0.05,P＜0.01);increased mineralization and calcium nodule formation;increased expressions of Col-Ⅰ,OCN,OPN mRNA and OPG protein(P＜0.05,P＜0.01);decreased RANKL protein expression(P＜0.05,P＜0.01);and reduced ROS levels.CONCLUSION Shuangyi Capsules ameliorate Dex-induced osteoporosis in mice by suppressing osteoclast overactivation,enhancing osteoblast activity,and stimulating bone formation through modulation of Col-Ⅰ,OCN,OPN mRNA and OPG/RANKL protein levels.

Objective To investigate the antimicrobial resistance of clinical isolates from elderly patients(≥65 years)in major medical institutions across China.Methods Bacterial strains were isolated from elderly patients in 52 hospitals participating in the CHINET Antimicrobial Resistance Surveillance Program during the period from 2015 to 2021.Antimicrobial susceptibility test was carried out by disk diffusion method and automated systems according to the same CHINET protocol.The data were interpreted in accordance with the breakpoints recommended by the Clinical and Laboratory Standards Institute(CLSI)in 2021.Results A total of 514 715 nonduplicate clinical isolates were collected from elderly patients in 52 hospitals from January 1,2015 to December 31,2021.The number of isolates accounted for 34.3％of the total number of clinical isolates from all patients.Overall,21.8％of the 514 715 strains were gram-positive bacteria,and 78.2％were gram-negative bacteria.Majority(90.9％)of the strains were isolated from inpatients.About 42.9％of the strains were isolated from respiratory specimens,and 22.9％were isolated from urine.More than half(60.7％)of the strains were isolated from male patients,and 39.3％isolated from females.About 51.1％of the strains were isolated from patients aged 65-＜75 years.The prevalence of methicillin-resistant strains(MRSA)was 38.8％in 32 190 strains of Staphylococcus aureus.No vancomycin-or linezolid-resistant strains were found.The resistance rate of E.faecalis to most antibiotics was significantly lower than that of Enterococcus faecium,but a few vancomycin-resistant strains(0.2％,1.5％)and linezolid-resistant strains(3.4％,0.3％)were found in E.faecalis and E.faecium.The prevalence of penicillin-susceptible S.pneumoniae(PSSP),penicillin-intermediate S.pneumoniae(PISP),and penicillin-resistant S.pneumoniae(PRSP)was 94.3％,4.0％,and 1.7％in nonmeningitis S.pneumoniae isolates.The resistance rates of Klebsiella spp.(Klebsiella pneumoniae 93.2％)to imipenem and meropenem were 20.9％and 22.3％,respectively.Other Enterobacterales species were highly sensitive to carbapenem antibiotics.Only 1.7％-7.8％of other Enterobacterales strains were resistant to carbapenems.The resistance rates of Acinetobacter spp.(Acinetobacter baumannii 90.6％)to imipenem and meropenem were 68.4％and 70.6％respectively,while 28.5％and 24.3％of P.aeruginosa strains were resistant to imipenem and meropenem,respectively.Conclusions The number of clinical isolates from elderly patients is increasing year by year,especially in the 65-＜75 age group.Respiratory tract isolates were more prevalent in male elderly patients,and urinary tract isolates were more prevalent in female elderly patients.Klebsiella isolates were increasingly resistant to multiple antimicrobial agents,especially carbapenems.Antimicrobial resistance surveillance is helpful for accurate empirical antimicrobial therapy in elderly patients.

Objective To investigate the distribution and antimicrobial resistance profiles of clinically isolated Haemophilus influenzae and Moraxella catarrhalis in hospitals across China from 2015 to 2021,and provide evidence for rational use of antimicrobial agents.Methods Data of H.influenzae and M.catarrhalis strains isolated from 2015 to 2021 in CHINET program were collected for analysis,and antimicrobial susceptibility testing was performed by disc diffusion method or automated systems according to the uniform protocol of CHINET.The results were interpreted according to the CLSI breakpoints in 2022.Beta-lactamases was detected by using nitrocefin disk.Results From 2015 to 2021,a total of 43 642 strains of Haemophilus species were isolated,accounting for 2.91％of the total clinical isolates and 4.07％of Gram-negative bacteria in CHINET program.Among the 40 437 strains of H.influenzae,66.89％were isolated from children and 33.11％were isolated from adults.More than 90％of the H.influenzae strains were isolated from respiratory tract specimens.The prevalence of β-lactamase was 53.79％in H.influenzae strains.The H.influenzae strains isolated from children showed higher resistance rate than the strains isolated from adults.Overall,779 strains of H.influenzae did not produce β-lactamase but were resistant to ampicillin(BLNAR).Beta-lactamase-producing strains showed significantly higher resistance rates to these antimicrobial agents than the β-lactamase-nonproducing strains.Of the 16 191 M.catarrhalis strains,80.06％were isolated from children and 19.94％isolated from adults.M.catarrhalis strains were mostly susceptible to both amoxicillin-clavulanic acid and cefuroxime,evidenced by resistance rate lower than 2.0％.Conclusions The emergence of antibiotic-resistant H.influenzae due to β-lactamase production poses a challenge for clinical anti-infective treatment.Therefore,it is very important to implement antibiotic resistance surveillance for H.influenzae and guide rational antibiotic use.All local clinical microbiology laboratories should actively improve antibiotic susceptibility testing and strengthen antibiotic resistance surveillance for H.influenzae.