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 effect and mechanism of leucine zipper/EF-hand-containing transmembrane protein 1(LETM1)on proliferation,migration,apoptosis,osteogenic differentiation,and tumorigenesis in vivo of human osteosarcoma MG63 and 143B cells.Methods The osteosarcoma MG63 and 143B cells were divided into blank control group(without adenovirus infection),negative control group(sh-NC group,infected with RNAi negative control virus),and LETM1 knockdown group(sh-LETM1 group,infected with sh-LETM1 adenovirus).Western blotting was performed to detect LETM1 expression in normal human osteoblasts hFOB1.19 and osteosarcoma cells,and to verify the knockdown effect of adenovirus;cell clone formation assays and CCK-8 method were used to detect the proliferation of MG63 and 143B cells;wound-healing assay and Transwell assay were used to test cell migration;DAPI staining and Annexin V-APC/7-AAD flow cytometry double staining were used to detect the apoptosis of MG63 and 143B cells;alkaline phosphatase(ALP)staining and Alizarin Red S staining were used to evaluate early and late osteogenic differentiation of MG63 and 143B cells.Ten nude mice were divided into sh-NC group(n=5,injected subcutaneously into nude mice with 143B cells infected with RNAi negative control virus)and sh-LETM1 group(n=5,injected subcutaneously into nude mice with 143B cells infected with sh-LETM1 adenovirus),and nude mice subcutaneous tumor formation assay was used to examine the in vivo tumor-forming ability of 143B cells in each group.Results Western blotting showed that the expression of LETM1 protein in osteosarcoma MG63 and 143B cells was significantly higher than that in human normal osteoblasts hFOB1.19(P<0.05),and that the expression of LETM1 protein was markedly reduced after injection with sh-LETM1 adenovirus in MG63 and 143B cells.The results of cell clone formation assay and CCK-8 assay indicated that in MG63 and 143B osteosarcoma cells,the clone formation ability and proliferation ability were significantly reduced in sh-LETM1 group compared with sh-NC group and blank control group(P<0.01).The results of wound-healing assay and Transwell assay demonstrated that in MG63 and 143B osteosarcoma cells,the cell migration rate in sh-LETM1 group was significantly lower than that in sh-NC group and blank control group(P<0.01).DAPI staining and flow cytometry results revealed that the apoptosis rate in sh-LETM1 group was significantly higher than those in MG63 and 143B osteosarcoma cells in sh-NC group(P<0.01).Alkaline phosphatase staining and Alizarin red S staining experiments showed more stained areas and calcium salt nodules in MG63 and 143B osteosarcoma cells in sh-LETM1 group than those in sh-NC group and blank control group.The results of the subcutaneous tumor formation assay in nude mice indicated that subcutaneous tumor formation ability was reduced in 143B sh-LETM1 group compared with 143B sh-NC group.Conclusion LETM1 promotes the proliferation,migration and in vivo tumor formation of MG63 and 143B osteosarcoma cells and the mechanism may be related to the inhibition of apoptosis and osteogenic differentiation.

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.

[Abstract] Objective To investigate the effect of wingless-type MMTV integration site family member 5b(Wnt5b) gene overexpression mediated by recombinant adenovirus on the differentiation of mouse embryonic liver stem cells and repair of chronic liver injury in mice. Methods Recombinant adenoviruses expressing Wnt5b and green fluorescent protein (GFP) were applied respectively to infect mouse fetal liver stem cells HP14-19, and induced its differentiation and verified the expression of Wnt5b through Real-time PCR and Western blotting. It also applied indocyanine grean(ICG) uptake experiment and periodic acid-schiff(PAS) staining to detect the differentiation ability of HP14-19 into hepatocyte-like cells. The Real-time PCR was chosen to detect hepatocyte markers albumin (Alb) and cytokeratin 18 (CK18) expression. Forty-eight experimental male BALB/ c mice were randomly divided into control group, model group, stem cell treatment group and Wnt5b modified stem cell treatment group. The carbon tetrachloride(CCl

Objective To investigate the effect of knock⁃down 3⁃phosphoglycerin dehydrogenase (PHGDH) targeting energy metabolism on malignant biological behavior and osteogenic differentiation of human osteosarcoma 143B cells. Methods Real⁃time PCR and Western blotting were used to detect the expression of PHGDH in osteoblasts hFOB1. 19 and osteosarcoma cells TE85, MG63 and 143B with different malignant degrees. The short hairpin RNA (shRNA)⁃PHGDH recombinant plasmid was transfected into 143 B cells by liposome transfection method. The expression of PHGDH was detected by Real⁃time PCR and Western blotting. Crystal violet staining, cell counting and CCK⁃8 assay were used to detect cell proliferation; wound healing assay was used to detect cell parallel migration ability, and Transwell assay was used to detect cell vertical migration and invasion ability. Annexin V⁃FITC/ PI double staining and DAPI staining were used to detect apoptosis; Alkaline phosphatase(ALP) staining and alizarin red S staining were used to detect osteogenic differentiation. Western blotting was used to detect the expression of Runt related transcription factor 2 (Runx2) and osteocalcin (OC) . The expression of genes related to energy metabolism, glucose transporter⁃1 (GLUT1), 6⁃ phosphofructokinase⁃1(PFK1), pyruvate kinae subtype M2 (PKM2), lactate dehydrogenase A (LDHA) was detected by Real⁃time PCR. Lactic acid secretion was detected by lactic acid detection kit. Adenosine triphosphate(ATP) production was detected by ATP detection kit. Results The expression of PHGDH in 143B cells was significantly higher than that in hFOB1. 19, MG63 and TE85 cells (P < 0. 01) . After the transfection of shRNA⁃PHGDH recombinant plasmid, the expression of PHGDH in 143 B cells decreased (P<0. 01), proliferation ability decreased (P<0. 01), cell migration and invasion ability decreased (P < 0. 01), apoptosis rate increased (P < 0. 01), ALP staining positive rate increased (P < 0. 01), alizarin red staining positive rate increased (P < 0. 05), Runx2 (P < 0. 05) and OC expression increased (P < 0. 01), expression of genes related to energy metabolism (GLUT1, PFK1, PKM2, LDHA) decreased (P < 0. 01), lactic acid decreased (P < 0. 01), ATP increased (P < 0. 05) . Conclusion Knocking down of PHGDH can inhibit the proliferation, migration and invasion of human osteosarcoma 143B cells through energy metabolism, promote their apoptosis and promote their osteogenic differentiation.

Objective: To analyze the clinical epidemiological characteristics including composition of pathogens , clinical characteristics, and disease prognosis acute bacterial meningitis (ABM) in Chinese children. Methods: A retrospective analysis was performed on the clinical and laboratory data of 1 610 children <15 years of age with ABM in 33 tertiary hospitals in China from January 2019 to December 2020. Patients were divided into different groups according to age,<28 days group, 28 days to <3 months group, 3 months to <1 year group, 1-<5 years of age group, 5-<15 years of age group; etiology confirmed group and clinically diagnosed group according to etiology diagnosis. Non-numeric variables were analyzed with the Chi-square test or Fisher's exact test, while non-normal distrituction numeric variables were compared with nonparametric test. Results: Among 1 610 children with ABM, 955 were male and 650 were female (5 cases were not provided with gender information), and the age of onset was 1.5 (0.5, 5.5) months. There were 588 cases age from <28 days, 462 cases age from 28 days to <3 months, 302 cases age from 3 months to <1 year of age group, 156 cases in the 1-<5 years of age and 101 cases in the 5-<15 years of age. The detection rates were 38.8% (95/245) and 31.5% (70/222) of Escherichia coli and 27.8% (68/245) and 35.1% (78/222) of Streptococcus agalactiae in infants younger than 28 days of age and 28 days to 3 months of age; the detection rates of Streptococcus pneumonia, Escherichia coli, and Streptococcus agalactiae were 34.3% (61/178), 14.0% (25/178) and 13.5% (24/178) in the 3 months of age to <1 year of age group; the dominant pathogens were Streptococcus pneumoniae and the detection rate were 67.9% (74/109) and 44.4% (16/36) in the 1-<5 years of age and 5-<15 years of age . There were 9.7% (19/195) strains of Escherichia coli producing ultra-broad-spectrum β-lactamases. The positive rates of cerebrospinal fluid (CSF) culture and blood culture were 32.2% (515/1 598) and 25.0% (400/1 598), while 38.2% (126/330)and 25.3% (21/83) in CSF metagenomics next generation sequencing and Streptococcus pneumoniae antigen detection. There were 4.3% (32/790) cases of which CSF white blood cell counts were normal in etiology confirmed group. Among 1 610 children with ABM, main intracranial imaging complications were subdural effusion and (or) empyema in 349 cases (21.7%), hydrocephalus in 233 cases (14.5%), brain abscess in 178 cases (11.1%), and other cerebrovascular diseases, including encephalomalacia, cerebral infarction, and encephalatrophy, in 174 cases (10.8%). Among the 166 cases (10.3%) with unfavorable outcome, 32 cases (2.0%) died among whom 24 cases died before 1 year of age, and 37 cases (2.3%) had recurrence among whom 25 cases had recurrence within 3 weeks. The incidences of subdural effusion and (or) empyema, brain abscess and ependymitis in the etiology confirmed group were significantly higher than those in the clinically diagnosed group (26.2% (207/790) vs. 17.3% (142/820), 13.0% (103/790) vs. 9.1% (75/820), 4.6% (36/790) vs. 2.7% (22/820), χ²=18.71, 6.20, 4.07, all P<0.05), but there was no significant difference in the unfavorable outcomes, mortility, and recurrence between these 2 groups (all P>0.05). Conclusions: The onset age of ABM in children is usually within 1 year of age, especially <3 months. The common pathogens in infants <3 months of age are Escherichia coli and Streptococcus agalactiae, and the dominant pathogen in infant ≥3 months is Streptococcus pneumoniae. Subdural effusion and (or) empyema and hydrocephalus are common complications. ABM should not be excluded even if CSF white blood cell counts is within normal range. Standardized bacteriological examination should be paid more attention to increase the pathogenic detection rate. Non-culture CSF detection methods may facilitate the pathogenic diagnosis.
Adolescent ; Brain Abscess ; Child ; Child, Preschool ; Escherichia coli ; Female ; Humans ; Hydrocephalus ; Infant ; Infant, Newborn ; Male ; Meningitis, Bacterial/epidemiology* ; Retrospective Studies ; Streptococcus agalactiae ; Streptococcus pneumoniae ; Subdural Effusion ; beta-Lactamases

Objective:To investigate the distribution and antimicrobial resistance profile of clinical bacteria isolated from blood culture in China.Methods:The clinical bacterial strains isolated from blood culture from member hospitals of Blood Bacterial Resistant Investigation Collaborative System (BRICS) were collected during January 2018 to December 2019. Antibiotic susceptibility tests were conducted with agar dilution or broth dilution methods recommended by US Clinical and Laboratory Standards Institute (CLSI). WHONET 5.6 was used to analyze data.Results:During the study period, 14 778 bacterial strains were collected from 50 hospitals, of which 4 117 (27.9%) were Gram-positive bacteria and 10 661(72.1%) were Gram-negative bacteria. The top 10 bacterial species were Escherichia coli (37.2%), Klebsiella pneumoniae (17.0%), Staphylococcus aureus (9.7%), coagulase-negative Staphylococci (8.7%), Pseudomonas aeruginosa (3.7%), Enterococcus faecium (3.4%), Acinetobacter baumannii(3.4%), Enterobacter cloacae (2.9%), Streptococci(2.8%) and Enterococcus faecalis (2.3%). The the prevalence of methicillin-resistant S. aureus (MRSA) and methicillin-resistant coagulase-negative Staphylococcus were 27.4% (394/1 438) and 70.4% (905/1 285), respectively. No glycopeptide-resistant Staphylococcus was detected. More than 95% of S. aureus were sensitive to amikacin, rifampicin and SMZco. The resistance rate of E. faecium to vancomycin was 0.4% (2/504), and no vancomycin-resistant E. faecalis was detected. The ESBLs-producing rates in no carbapenem-resistance E. coli, carbapenem sensitive K. pneumoniae and Proteus were 50.4% (2 731/5 415), 24.6% (493/2001) and 35.2% (31/88), respectively. The prevalence of carbapenem-resistance in E. coli and K. pneumoniae were 1.5% (85/5 500), 20.6% (518/2 519), respectively. 8.3% (27/325) of carbapenem-resistance K. pneumoniae was resistant to ceftazidime/avibactam combination. The resistance rates of A. baumannii to polymyxin and tigecycline were 2.8% (14/501) and 3.4% (17/501) respectively, and that of P. aeruginosa to carbapenem were 18.9% (103/546). Conclusions:The surveillance results from 2018 to 2019 showed that the main pathogens of bloodstream infection in China were gram-negative bacteria, while E. coli was the most common pathogen, and ESBLs-producing strains were in majority; the MRSA incidence is getting lower in China; carbapenem-resistant E. coli keeps at a low level, while carbapenem-resistant K. pneumoniae is on the rise obviously.

OBJECTIVE: To comparatively study the toxicity of four metal-containing nanoparticles (MNPs) and their chemical counterparts to the air-blood barrier (ABB) permeability using an in vitro model. METHODS: ABB model, which was developed via the co-culturing of A549 and pulmonary capillary endothelium, was exposed to spherical CuO-NPs (divided into CuO-40, CuO-80, and CuO-100 based on particle size), nano-Al2O3 (sheet and short-rod-shaped), nano-ZnO, nano-PbS, CuSO4, Al2(SO4)3, Zn(CH3COO)2, and Pb(NO3)2 for 60 min. Every 10 min following exposure, the cumulative cleared volume (ΔTCL) of Lucifer yellow by the model was calculated. A clearance curve was established using linear regression analysis of ΔTCL versus time. Permeability coefficient (P) was calculated based on the slope of the curve to represent the degree of change in the ABB permeability. RESULTS: The results found the increased P values of CuO-40, CuO-80, sheet, and short-rod-shaped nano-Al2O3, Al2(SO4)3, and Pb(NO3)2. Among them, small CuO-40 and CuO-80 were stronger than CuO-100 and CuSO4; no difference was observed between Al2(SO4)3 and sheet and short-rod-shaped nano-Al2O3; and nano-PbS was slightly weaker than Pb(NO3)2. So clearly the MNPs possess diverse toxicity. CONCLUSION ABB permeability abnormality means pulmonary toxicity potential. More studies are warranted to understand MNPs toxicity and ultimately control the health hazards.
A549 Cells ; Blood-Air Barrier ; metabolism ; Epithelium ; metabolism ; Humans ; Metal Nanoparticles ; toxicity ; Particle Size ; Permeability

OBJECTIVETo investigate the changes of tumor necrosis factor-α (TNF-α) and transforming growth factor-β (TGF-β) in mice with cholestatic cirrhosis and their role in regulating the balance of liver stem cell differentiation.

METHODSBalb/c mice were subjected to bile duct ligation (BDL), and serum biochemical parameters were measured and hepatic histopathology was observed using HE staining to evaluate the modeling of cholestatic cirrhosis. Immunohistochemistry and Western blotting were used to detect the changes of TNF-α and TGF-β in the mice after modeling. Mouse embryonic hepatic stem cells (HP14-19) were treated with different concentrations of TNF-α and TGF-β, and the cell differentiation was assessed using Western blotting, real-time PCR, and PAS staining.

RESULTSThe mice receiving BDL showed significantly increased blood biochemical parameters (P<0.05), and HE staining revealed obviously increased collagen fibers in the liver with significantly increased expressions of TNF-α and TGF-β (P<0.05). In HP14-19 cells, induction with TNF-α and TGF-β for 3 days did not cause significant changes in cell differentiation, but induction for 5 days resulted in significantly increases intensity of PAS staining in the cells. The cells induced with 20, 40, and 80 ng/mL TNF-α for 5 days exhibited a significantly stronger expression of cytokeratin 18 than cytokeratin 19 (P<0.05), while induction with 20, 40, and 80 ng/mL TGF-β produced opposite changes in cytokeratin 18 and cytokeratin 19 expressions. Further induction of the cells with TNF-α and TGF-β for 10 days, did not alter the expression patterns of cytokeratin 18 and cytokeratin 19 observed on day 5, but their protein expression levels and PAS staining intensity of the cells were enhanced and their mRNA expressions became lowered.

CONCLUSIONCommon bile duct ligation can induce conditions simulating cholestatic cirrhosis in mice. TNF-α and TGF-β are elevated in cholestatic cirrhosis and play opposite roles in regulating the differentiation balance of liver stem cells: the former promotes the differentiation of liver stem cells into hepatocytes, while the latter promotes the cell differentiation into colangiocytes.

[Objective]To study the relationship between bridging septa thickening in the perinephric space and split renal function in acute unilateral upper urinary tract obstruction.[Methods]50 patients with acute unilateral upper urinary tract obstruction by calculus were analyzed retrospectively. According to the images of multi-slice spiral CT (MSCT)scanning,all cases were divided into thickened bridging septa group(n=25)and normal bridging septa group (n=25),The CT values of renal cortical in the plain(CTp)and renal cortical enhancing(CTe)phase were measured, the difference of increasement value(CTe-CTp)and the CT value ratio of the ipsilateral and opposite in renal cortical phase was analyzed by independent sample T test.[Results]The CT increasement value of bridging septa thickening and normal group were(103±30)HU and(128±24)HU respectively,the difference between the two groups was statistically significant(P<0.01);and CTac/CTuc were 0.81±0.13 and 0.96±0.06 respectively(P<0.01).[Conclusion]Thickening of bridging septa in the perinephric space with acute unilateral upper urinary tract obstruction will weaken the enhancement of renal cortical,and increased the likelihood of split renal function impairing.