Objective Recombinase-aided polymerase chain reaction(RAP)is a sensitive,single-tube,two-stage nucleic acid amplification method.This study aimed to develop an assay that can be used for the early diagnosis of three types of bacteremia caused by Staphylococcus aureus(SA),Pseudomonas aeruginosa(PA),and Acinetobacter baumannii(AB)in the bloodstream based on recombinant human mannan-binding lectin protein(M1 protein)-conjugated magnetic bead(M1 bead)enrichment of pathogens combined with RAP. Methods Recombinant plasmids were used to evaluate the assay sensitivity.Common blood influenza bacteria were used for the specific detection.Simulated and clinical plasma samples were enriched with M1 beads and then subjected to multiple recombinase-aided PCR(M-RAP)and quantitative PCR(qPCR)assays.Kappa analysis was used to evaluate the consistency between the two assays. Results The M-RAP method had sensitivity rates of 1,10,and 1 copies/μL for the detection of SA,PA,and AB plasmids,respectively,without cross-reaction to other bacterial species.The M-RAP assay obtained results for<10 CFU/mL pathogens in the blood within 4 h,with higher sensitivity than qPCR.M-RAP and qPCR for SA,PA,and AB yielded Kappa values of 0.839,0.815,and 0.856,respectively(P<0.05). Conclusion An M-RAP assay for SA,PA,and AB in blood samples utilizing M1 bead enrichment has been developed and can be potentially used for the early detection of bacteremia.

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 investigate the molecular mechanism of autophagy and apoptosis induced by ultrafine carbon black in human bronchial epithelial cells (BEAS-2B cells), and to study the intervention effect and mechanism of N-acetylcysteine (NAC) on ultrafine carbon black-induced oxidative damage in BEAS-2B cells.Methods:In March 2023, BEAS-2B cells were used as research object, an in vitro airway model exposed to ultrafine carbon black was constructed. A control group and three carbon black exposure groups (50, 100, 200 μg/ml) were set up, and the cells were treated with corresponding concentrations of ultrafine carbon black for 24 hours. In addition, the experiment was divided into control group, NAC+ control group, 100 μg/ml carbon black exposure group and NAC+ exposure group. The corresponding groups were treated with 2 mmol/L NAC for 1 h and 100 μg/ml ultrafine carbon black for 24 h, respectively. Cell viability was measured by CCK-8 assay. Intracellular reactive oxygen species (ROS) level was detected by chemical fluorescence method. The activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT), as well as the content of malondialdehyde (MDA) were detected by colorimetry. The mRNA and protein expressions of autophagy-related genes[Atg5, Atg7, Beclin1, microtubule-associated protein light chain 3B (LC3B), p62 and lysosome-associated membrane protein 2 (LAMP2) ] and apoptosis-related genes [B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), Caspase3, Caspase9 and poly (ADP-ribose) polymerase 1 (PARP1) ] were determined by fluorescence quantitative PCR and Western blot. Cell apoptosis was determined by flow cytometry.Results:Compared with the control group, the relative survival rates of BEAS-2B cells in 50, 100, 200 μg/ml carbon black exposure groups were significantly decreased, the levels of ROS and MDA were significantly increased, and the activities of SOD, GSH-Px and CAT were significantly decreased ( P<0.05). The relative survival rate, ROS and MDA levels, SOD, GSH-Px and CAT activities were significantly correlated with the exposure dose of ultrafine carbon black ( rs=-0.755, 0.826, 0.934, -0.810, -0.880, -0.840, P<0.05). Compared with the control group, the relative expression levels of Atg5, Atg7, Beclin1, LC3B, p62, LAMP2, Bax, Caspase3, Caspase9, PARP1 mRNA and Atg5, Atg7, Beclin1, LC3BⅡ, p62, LAMP2, Bax, cleaved Caspase3 (C-Caspase3), cleaved Caspase9 (C-Caspase9), cleaved PARP1 (C-PARP1) protein and the ratio of LC3BⅡ/LC3BⅠ in 50, 100 and 200 μg/ml carbon black exposure groups were significantly increased, while the relative expression levels of Bcl-2 mRNA and protein were significantly decreased ( P<0.05). The changes of the above indexes were significantly correlated with the exposure dose of carbon black ( rs=0.892, 0.879, 0.944, 0.892, 0.828, 0.880, 0.814, 0.794, 0.931, 0.918, 0.813, 0.866, 0.774, 0.695, 0.918, 0.761, 0.794, 0.944, 0.833, 0.866, 0.905, -0.886, -0.748, P<0.05). Compared with 100 μg/ml carbon black exposure group, the relative survival rate, the activities of SOD, GSH-Px and CAT in NAC+exposure group were significantly increased, while the levels of ROS and MDA were significantly decreased, and the relative expression levels of LC3B, p62 and Caspase3 mRNA and protein as well as the ratio of LC3BⅡ/LC3BⅠ were significantly decreased, and the differences were statistically significant ( P<0.05). Compared with the control group, the apoptosis rates of BEAS-2B cells in 50, 100, 200 μg/ml carbon black exposure groups were significantly increased ( P<0.05), and there was a significant positive correlation between ultrafine carbon black exposure dose and cell apoptosis rate ( rs=0.944, P<0.05). While compared with 100 μg/ml carbon black exposure group, the apoptosis rate of NAC+exposure group was significantly decreased, and the difference was statistically significant ( P<0.05) . Conclusion:Cell autophagy and apoptosis may be important pathophysiological mechanisms of ultrafine carbon black-induced oxidative damage in BEAS-2B cells. NAC can alleviate the occurrence of BEAS-2B cell damage caused by ultrafine carbon black by regulating oxidative stress and the cascading autophagy and apoptosis pathways.

Objective To study the change of lipidomics in chronic cadmium-exposed mice,thereby screening out lipid subclasses,lipid molecules and enriched metabolic pathways with significant differences.Methods Twelve SPF male C57BL/6J mice(8 weeks old)were randomly divided into the control group(normal water feeding)and the experimental group[cadmium water(0.6 mg/L of CdCl2)feeding],with 6 mice in each group.Mice were sacrificed after 6 months of cadmium exposure,and fresh liver tissues were collected immediately.Lipid oil red O staining and lipidomics analysis were performed on liver tissue.Results Compared with the control group,the liver tissue of mice in the experimental group did not appear red after lipid oil red O staining.Seventeen lipid subclasses with significant differences and 144 lipid molecules with significant differences were screened out by lipidomics.These lipid molecules with significant differences were enriched in glycerophospholipid metabolism,linoleic acid metabolism,alpha-linolenic acid metabolism,glycosylphosphati-dylinositol biosynthesis,glycerolipid metabolism and arachidonic acid metabolism by KEGG.Conclusion This study reveals that chronic cadmium exposure can induce the disorder of lipid subclasses and lipid metabolites in the liver of mice,which provides a basis for understanding the non-alcoholic fatty liver disease caused by chronic cadmium exposure.

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.

Given the vital role of vasculature in solid tumors, the potential of vascular disrupting therapy in the treatment of triple-negative breast cancer (TNBC) is promising. In this study, we prepared the acid-sensitive liposome PPD/CA4P/Lip-Rap loaded with the vascular disrupting agent CA4P and the anti-angiogenic drug rapamycin (Rap) to explore the potential of the vascular disrupting strategy in TNBC. PPD/CA4P/Lip-Rap was characterized by ¹H NMR, dynamic light scattering, and transmission electron microscopy. Its drug loading and acid sensitivity were determined. The particle size of PPD/CA4P/Lip-Rap is 161.53 ± 1.89 nm, the zeta potential is -20.03 ± 0.9 mV and it demonstrated good drug release on acidic sensitivity responses. CCK-8 experiments proved that Rap can enhance the ability of CA4P to destroy tumor vascular endothelial cells. Rap can kill marginal residual tumor cells, suppress tumor recurrence. Nanocarriers can further enhance the therapeutic effect. Western blot (WB) showed that Rap decreased the expression of hypoxia-inducible factor-1α (HIF-1α) via the mTOR/p70S6K and mTOR/4E-BP1 pathways. Thus, tumor hypoxia activation and angiogenesis were inhibited. PPD/CA4P/Lip-Rap can effectively destroy tumor vessels, inhibit tumor angiogenesis and recurrence, and provide a new strategy for the treatment of TNBC by targeting disruption of tumor vessels.

Uncovering the risk factors of pulmonary hypertension and its mechanisms is crucial for the prevention and treatment of the disease.In the current study,we showed that experimental periodontitis,which was established by ligation of molars followed by orally smearing subgingival plaques from patients with periodontitis,exacerbated hypoxia-induced pulmonary hypertension in mice.Mechanistically,periodontitis dysregulated the pulmonary microbiota by promoting ectopic colonization and enrichment of oral bacteria in the lungs,contributing to pulmonary infiltration of interferon gamma positive(IFNγ+)T cells and aggravating the progression of pulmonary hypertension.In addition,we identified Prevotella zoogleoformans as the critical periodontitis-associated bacterium driving the exacerbation of pulmonary hypertension by periodontitis,and the exacerbation was potently ameliorated by both cervical lymph node excision and IFNγ neutralizing antibodies.Our study suggests a proof of concept that the combined prevention and treatment of periodontitis and pulmonary hypertension are necessary.

Objective To investigate the regulatory effect of swimming exercise(SE)on lipid metabolism in nonalcoholic fatty liver disease(NAFLD)mice.Methods A total of 27 C57BL/6J mice were divided into the control group(normal diet),high fat diet(HFD)group and HFD+SE group,with 9 mice in each group.Twelve weeks later,liver tissues were collected for untargeted lipidomics detection by LC-MS.Dimensional statistical analysis of lipidomics profiles was carried out by constructing OPLS-DA model,and combined with the t-test,the lipids with OPLS-DA VIP>1,P<0.05 were screened out from all samples as significantly different lipids.Results There were 81 different lipids between HFD group and the control group;and there were 27 different lipids between HFD+SE group and HFD group.The different lipids mainly belong to glycerides,glycerophospholipids and sphingomyelins.Conclusion Lipid metabolism profile of NAFLD mice has been changed,and swimming exercise can improve lipid metabolism of NAFLD mice.

Objective To monitor the susceptibility of clinical isolates to antimicrobial agents in tertiary hospitals in major regions of China in 2022.Methods Clinical isolates from 58 hospitals in China were tested for antimicrobial susceptibility using a unified protocol based on disc diffusion method or automated testing systems.Results were interpreted using the 2022 Clinical &Laboratory Standards Institute(CLSI)breakpoints.Results A total of 318 013 clinical isolates were collected from January 1,2022 to December 31,2022,of which 29.5％were gram-positive and 70.5％were gram-negative.The prevalence of methicillin-resistant strains in Staphylococcus aureus,Staphylococcus epidermidis and other coagulase-negative Staphylococcus species(excluding Staphylococcus pseudintermedius and Staphylococcus schleiferi)was 28.3％,76.7％and 77.9％,respectively.Overall,94.0％of MRSA strains were susceptible to trimethoprim-sulfamethoxazole and 90.8％of MRSE strains were susceptible to rifampicin.No vancomycin-resistant strains were found.Enterococcus faecalis showed significantly lower resistance rates to most antimicrobial agents tested than Enterococcus faecium.A few vancomycin-resistant strains were identified in both E.faecalis and E.faecium.The prevalence of penicillin-susceptible Streptococcus pneumoniae was 94.2％in the isolates from children and 95.7％in the isolates from adults.The resistance rate to carbapenems was lower than 13.1％in most Enterobacterales species except for Klebsiella,21.7％-23.1％of which were resistant to carbapenems.Most Enterobacterales isolates were highly susceptible to tigecycline,colistin and polymyxin B,with resistance rates ranging from 0.1％to 13.3％.The prevalence of meropenem-resistant strains decreased from 23.5％in 2019 to 18.0％in 2022 in Pseudomonas aeruginosa,and decreased from 79.0％in 2019 to 72.5％in 2022 in Acinetobacter baumannii.Conclusions The resistance of clinical isolates to the commonly used antimicrobial agents is still increasing in tertiary hospitals.However,the prevalence of important carbapenem-resistant organisms such as carbapenem-resistant K.pneumoniae,P.aeruginosa,and A.baumannii showed a downward trend in recent years.This finding suggests that the strategy of combining antimicrobial resistance surveillance with multidisciplinary concerted action works well in curbing the spread of resistant bacteria.

Objective To investigate the distribution and antimicrobial resistance profiles of the common pathogens isolated from urine from 2015 to 2021 in the CHINET Antimicrobial Resistance Surveillance Program.Methods The bacterial strains were isolated from urine and identified routinely in 51 hospitals across China in the CHINET Antimicrobial Resistance Surveillance Program from 2015 to 2021.Antimicrobial susceptibility was determined by Kirby-Bauer method,automatic microbiological analysis system and E-test according to the unified protocol.Results A total of 261 893 nonduplicate strains were isolated from urine specimen from 2015 to 2021,of which gram-positive bacteria accounted for 23.8％(62 219/261 893),and gram-negative bacteria 76.2％(199 674/261 893).The most common species were E.coli(46.7％),E.faecium(10.4％),K.pneumoniae(9.8％),E.faecalis(8.7％),P.mirabilis(3.5％),P.aeruginosa(3.4％),SS.agalactiae(2.6％),and E.cloacae(2.1％).The strains were more frequently isolated from inpatients versus outpatients and emergency patients,from females versus males,and from adults versus children.The prevalence of ESBLs-producing strains in E.coli,K.pneumoniae and P.mirabilis was 53.2％,52.8％and 37.0％,respectively.The prevalence of carbapenem-resistant strains in E.coli,K.pneumoniae,P.aeruginosa and A.baumannii was 1.7％,18.5％,16.4％,and 40.3％,respectively.Lower than 10％of the E.faecalis isolates were resistant to ampicillin,nitrofurantoin,linezolid,vancomycin,teicoplanin and fosfomycin.More than 90％of the E.faecium isolates were ressitant to ampicillin,levofloxacin and erythromycin.The percentage of strains resistant to vancomycin,linezolid or teicoplanin was＜2％.The E.coli,K.pneumoniae,P.aeruginosa and A.baumannii strains isolated from ICU inpatients showed significantly higher resistance rates than the corresponding strains isolated from outpatients and non-ICU inpatients.Conclusions E.coli,Enterococcus and K.pneumoniae are the most common pathogens in urinary tract infection.The bacterial species and antimicrobial resistance of urinary isolates vary with different populations.More attention should be paid to antimicrobial resistance surveillance and reduce the irrational use of antimicrobial agents.