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Objective To evaluate the utility of carbapenem inactivation method (CIM) in detecting carbapenemase-producing Acinetobacter baumannii.Methods A total of 121 strains of A. baumannii were identified and subjected to antimicrobial susceptibility testing by VITEK compact. Carbapenem inactivation method (CIM) was applied to detect the carbapenemase in the A. baumannii strains. The OXA-23 type carbapenemase-encoding genes were analyzed by common PCR method.Results Six-eight of the 121 strains showed resistance to imipenem and meropenem. PCR showed that 65 of the 68 strains carried OXA-23 gene. CIM was positive in 66 of the 68 strains. And 52 of the 121A. baumannii strains were susceptible to imipenem and meropenem. PCR showed that OXA-23 gene was negative in 49 of the 52 strains. CIM was negative in the 52 strains of non-carbapenemase-producing A. baumannii. Only one strain was resistant to imipenem but susceptible to meropenem. CIM was negative but QXA-23 was positive for this strain. The sensitivity and the specificity of CIM was 94.2% and 98.1% respectively in detecting carbapenemase-producing A. baumannii.Conclusions The results of CIM were consistent with the results obtained by PCR to detect the encoding gene of OXA-23. CIM is inexpensive, easier to operate and interpret than PCR method. CIM is applicable to detect OXA-23 type carbapenemase rapidly inA. baumannii.
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Objective The purpose of this study was to analyze the susceptibility profile of Acinetobacter baumannii to antimicrobial agents,and validate the results of different antimicrobial susceptibility testing methods,for improving the quality of antibiotic resistance monitoring data.Methods The susceptibility data of Hebei Provincial Antimicrobial Resistant Investigation Net were analyzed retrospectively and 126 strains ofA.baumannii were collected.The susceptibility ofA.baumannii to piperacillintazobactam,amikacin,gentamicin,ciprofloxacin,levofloxacin,ceftazidime,imipenem,and meropenem was tested by E-test,KirbyBauer method and VITEK system.Results The susceptibility results of the 126 A.baumannii strains showed that the susceptibility to piperacillin-tazobactam,amikacin,gentamicin,levofloxacin and ceftazidime was significantly different between the three methods (P＜0.05).The categorical agreement,major error,minor error,and very major error of Kirby-Bauer method were within acceptable range.There were evident difference in classification consistency for piperacillin-tazobactam,amikacin,levofloxacin between Kirby-Bauer method and VITEK (P＜0.05).Conclusions Different antimicrobial susceptibility testing methods may lead to different results of resistance monitoring data.Bias may be generated in antibiotic resistance surveillance if different methods are used.The susceptibility results of piperacillin-tazobactam,amikacin,levofloxacin derived from VITEK system should be validated by Kirby-Bauer or E-test method.
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Objective To investigate the antibiotic resistance in clinical isolates in the Second Hospital of Hebei Medical University from 2015 to 2016.Methods A total of 16 292 strains of non-duplicate bacterial strains were collected.The isolates were subjected to identification and antimicrobial susceptibility testing on VITEK 2-Compact system.The data were processed and analyzed using WHONET 5.6 software.Results Specifically,7 961 and 8 331 strains of pathogens were collected in 2015,2016,respectively.Gram-negative bacteria accounted for 62.0％ in 2015 and 66.9％ in 2016,respectively.The top five pathogens isolated in these two years were still Klebsiella pneumoniae,Escherichia coli,Acinetobacter baumannii,Pseudomonas aeruginosa,and Staphylococcus aureus.The proportion of K.pneumoniae increased to the first place in 2016 which accounted for 16.1％.Coagulase negative Staphylococcus in blood samples decreased from 42.6％ in 2015 to 30.0％ in 2016.Vancomycin resistant strains were not found in Staphylococcus.In 2015 and 2016,the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) was 56.2％ and 51.3％,respectively.The prevalence of methicillinresistant coagulase negative Staphylococcus (MRCNS)was 79.3％ and 63.1％,respectively.Enterococcus faecalis and Enterococcus faecium accounted for 25.2％ and 73.2％ respectively in the 911 strains of Enterococcus.In 2015 and 2016,3.1％ and 2.9％ of the E.faecium strains were resistant to vancomycin,respectively.In 2016,the prevalence of carbapenemresistant strains increased in K.pneumoniae,E.coli and E.cloacae.K.pneumoniae showed increasing resistance rate to all the antimicrobial agents tested except for gentamicin and amikacin.The percentage of the K.pneumoniae strains resistant to imipenem and meropenem increased from 19.3％,18.5％ in 2015 to 24.2％,23.1％,respectively.A.baumannii isolates were still highly resistant to the commonly used antibiotics in these two years,but relatively susceptible to polymyxin B,tigecycline,cefoperazone-sulbactam and minocycline (＜30％ resistant).P.aeruginosa isolates showed lower resistance rate to amikacin (11.7％),cefoperazonesulbactam (15.5％),piperacillin-tazobactam (18.7％),ceftazidime (20.1％),cefepime (21.9％).P.aeruginosa presented a trend of declining resistance to all the antimicrobial agents tested from 2015 to 2016,except aztreonam,to which the resistant P.aeruginosa strains increased from 27.0％ in 2015 to 34.7％ in 2016.Conclusions The antimicrobial susceptibility profile of clinical bacterial isolates has been changing constantly.We need to adopt effective infection prevention and control measures in hospital and further standardize and control the use of antibacterial agents.
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Objective To investigate the antimicrobial resistance of Streptococcus pneumoniae strains isolated from multiple medical institutions across Hebei Province in 2015.Methods The bacterial data were collected from 53 member hospitals of Hebei Antimicrobial Resistance Investigation Net (HEBARIN) according to the unified surveillance program in Hebei province.WHONET 5.6 was used to review,analyze and summarize the surveillance data.The results were interpreted according to CLSI guideline 2014.Results A total of 2 408 strains of S.pneumoniae were included in this analysis.S.pneumoniae was the third most frequently isolated gram positive bacteria.More than 95％ of these S.pneumoniae strains were susceptible to vancomycin and moxifloxacin.However,96.4％,89.3％ and 67.4％ of these strains were resistant to erythromycin,clindamycin,and trimethoprim-sulfamethoxazole,respectively.The antimicrobial susceptibility profile was similar between the strains isolated from adults and those isolates from children.Conclusions The antimicrobial resistance profile ofS.pneumoniae isolates in Hebei Province is generally consistent with the nation-wide data,except higher resistance level to a few antimicrobial agents.We should be alert to and control the emergence of resistant S.pneumoniae.
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Objective To investigate antimicrobial resistance and pathogen in hebei antibacterial resistance investigation net in 2012.Methods Antimicrobial susceptibility test was detected by Kirby-Bauer method or broth dilution test.Results were analyzed according to CLSI 2010 breakpoints.WHONET 5.5 software was used to analyze the data.Results A total of 10 504 clinical isolates were collected in 2012,of which gram negative bacilli and gram positive cocci accounted for 76.2%, 23.8%,respectively.The most common pathogen in gram-negative rod was E.coli,K.pneumoniae,P.aeruginosa, A.baumanii and E.cloacae respectively.The most common pathogen in gram-positive cocci was S.aureus,E.facium,E-.faecalis,S.pneumoniae and S.epidermidis.ESBL rate of E.coli and K.pneumoniae was 66.5 and 46.7%.The resistant rate of E.coli,K.pneumoniae,E.cloacae to imipenem was 0.1%,0.5%,8.9% and to meropenem was 0.1%,0.6%,4.2%, respectively.P.aeruginosa was resistant to imipenem and meropenem were 38.9% and 32.3%.A.baumanii was resistant to imipenem and meropenem were 5 6.5% and 5 9.7%.Methicillin-resistant strains accounted for an average of 5 7.5% in S.aureus and 87.3% in coagulase negative staphylococcus.Staphylococcus was still susceptible to minocycline and chloram-phenicol.No staphylococcal strains were found resistant to vancomycin,linezolid.But a few coagulase negative staphylococcal strains were resistant to teicoplanin.Conclusion Surveillance of antimicrobial agents played an important role in controlling hospital infection.
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Objective To investigate the expression of FcγRⅡb on peripheral B cells and its clinical significance in primary Sj(o)gren's syndrome (pSS).Methods FcγRⅡb expression on peripheral B cells from 19 pSS patients and 15 healthy controls was examined by flow cytometry.The levels of serum anti-SSA and SSB antibodies were determined using enzyme-linked immunosorbent assay (ELISA).Data were analyzed with t test,one-way ANOVA,SNK-q test and Pearson's correlation test.Results The percentage of memory CD19+CD27+ B cell subpopulation was significantly lower in pSS patients [ (20.8±2.7)％] when compared to normal controls [(37.8±2.2)％ ](t=-4.002,P＜0.01).The level of expression of FcγRⅡb in active pSS memory CD19+CD27+ B cells [ MFI(74±8)] was significantly reduced when compared to inactive [ MFI( 132±11)] and normal controls [ MFI (139±12)] (F=10.699,P＜0.01).The level of expression of FcγRⅡb on memory CD19+CD27+ B cells from pSS patients was inversely correlated with Sj(o)gren's syndrome disease activity index (SSDAI) (r=-0.744,P=0.0003 ).pSS patients with the serum anti-SSA/SSB antibodies positive group [ MFI(75+3),(48±7)] displayed a lower expression of FcγRⅡb on memory CD19+CD27+ B cell than in patients with the serum anti-SSA/SSB antibodies negative group [MFI( 122±11),(108±9)] (t=-4.336 and -3.776 respectively,the P value of both tests were less than 0.01).The level of expression of FcγRⅡb in the memory CD19+CD27+ B cells of patients with active pSS was inversely correlated with anti-SSA antibody titers (r=-0.685,P=0.014).Conclusion The expression of FcγRⅡb on peripheral memory B cells from active pSS patients is inversely correlated with SSDAI and is also inversely associated with anti-SSA antibody levels.Decreased expression of FcγRⅡb might play an important role in the pathogenesis of pSS.
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Objective To investigate the apoptosis of bone marrow mesenchymal stem cells(BMSCs)from systemic lupus erythematosus(SLE)patients and the expression of apoptotic molecules.Methods BMSCs were isolated from bone marrow of SLE patients and normal controls by density eentrifugation and adhesive culture in vitro.The apoptosis of BMSCs were evaluated by TUNEL assay.The expressions of Fas.Bcl-2 and the activity of Caspase 8 were detected by flow cytometry.Real-time PCR technique was used to determine the gene expressions of Fas,Bcl-2,Bax,Bcl-w,Caspase 8 and Apaf-1.Meanwhile,cytochrome C was detected by immunocytochemistry.Statistical analysis was conducted with t-test and Mann-Whitney rank test.Results The percentage of apoptotic BMSCs increased in SLE patients compared with healthy donors[(64±10)%vs [14±9)%,U=0,P0.05).Conclusion BMSCs from SLE patients undergo more apoptosis,the mechanisms may be associated with the down regulation of Bcl-2,up-regulation of Cytoehrome C in cytoplasm and the activation of Caspase 8,which directs the intrinsic and extrinsic apoptosis pathways.
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Objective To explore the role of intracellular reactive oxygen species (ROS) in the senescence of bone marrow mesenchymal stem cells(BMSCs)in patients with systemic lupus erythematosus(SLE) and the underlying mechanisms that controls the intracellular ROS levels in vitro. Methods Human bone marrow aspirates were collected from iliac of eight donors and eight SLE patients and cultured in vitro.Morphological appearance of BMSCs at different passages was examined by inverted microscope. Nuclear size was measured by fluorescence microscope. BMSCs were monitored using the senescence associated β-galacto-sidase (SAβ-gal) assay to characterize senescence in vitro. The quantification of intracellular ROS production was detected by flow cytometry. Real-time PCR technique was used to determine the gene expressions of PI3K, KRas, NRas and FoxO3 at transcription level. The expression of FoxO3, phospho-FoxO3 (p-FoxO3),AKT and phospho-AKT (p-AKT) protein were determined by Western blot analysis. Statistical analysis was conducted with t-test and Mann-Whitney rank test.Results There were no differences in morphology and nuclear size[(31.4±4.5) vs (28.2±4.8) μm, P=0.628] of BMSCs between SLE patients and normal controls.The percentage of SA β-gal positive BMSCs from SLE patients was higher than that from healthy controls [(31.8±9.0)% vs (12.4±0.7)%, P＜0.05]. Intracellular ROS levels of BMSCs from SLE patients increased more significantly than healthy donors in vitro (34600±9600 vs 17 958±5400, P＜0.05). No significant differences in the expression of PI3K, NRas, KRas and FoxO3 from SLE subjects were observed at mRNA levels compared with normal controls, though all showed a similar upward trend. The expression of p-FoxO3 and p-AKT of BMSCs from SLE patients increased significantly compared with healthy controls at protein levels.Conclusion These data suggest that BMSCs from SLE patients aged more quickly, with high SA β-gal activity and up-regulation of intracellular ROS, which is associated with up-regulation of p-FoxO3 and pAKT at protein levels. These results indicate that bone marrow mesenchymal cell senescence may be associated with the pathogcnesis of SLE by maintaining the lifespan of BMSCs.
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ObjectiveTo investigate the effect of IκB kinase (IKK-β) on migration and proliferation of bone marrow mesenchymal stem cells(BMSCs) from patients with systemic lupus erythematosus (SLE).MethodsHuman bone marrow aspirates were collected from iliac of six donors and six SLE patients and cultured in vitro.Migration of BMSCs were observed by wound healing and transwell migration assays.Proliferation of BMSCs was quantified by cell counting kit-8 assay.Total RNA was extracted and reverse transcribed into complementary DNA.Real-time PCR technique was used to determine the gene expression of IKK-β at transcription level.The expression of IKK-β and phospho-IKK-β(p-IKK-β) protein were determined by Western blotting analysis.Statistical analysis was conducted with or Mann-Whitney rank test.Results① The migration rate of BMSCs from SLE patients(5.2±3.8)‰ were significantly reduced as compared with normal controls (7.0±2.9)‰(P＜0.05 ).The proliferation of BMSCs of SLE patients (0.21±0.49)was lower than that from healthy controls ( 1.00±0.35 )(P＜0.05 ).②) No difference in IKK-β3 mRNA expression between SLE ( 1.9± 1.4) subjects and normal controls (1.9±2.4) (P＞0.05).IKK-β protein expression of BMSCs from SLE patients (1.41 ±0.19) increased significantly compared with healthy controls (0.93±1.24) (P＜0.05).③ Inhibitor of IKK-β caused a significant increase in cell migration (3.3±1.6)‰ and proliferation (1.13±0.26) of BMSCs from SLE patients compared with untreated cells (2.3±1.1)‰ and (0.81±0.17),respectively (P＜0.05).ConclusionMigration and proliferation of BMSCs are significantly decreased in SLE patients.IKK-β may be involved in migration and proliferation of BMSCs.
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Objectives To analyze the characteristics of antigenic genes of clinical Bordetella pertussis strains recently isolated by analyzing the sequence of pertussis toxin S1 subunit(ptxS1) , pertactin (Prn) , fimbriae 2 (Fim2) and fimbriae 3 (Fim3 ) genes of four clinical isolates. Methods The 4 clinical isolates were collected in 2002 in Shijiazhuang of Hebei province. Four strains were isolated from pertussis patient's nasopharyngeal aspirate. ptxS1, Prn, Fim2 and Fim3 genes of these strains were amplified and sequenced. The sequences of those genes were compared with those of the isolates in GenBank and the isoaltes used in the production of pertussis vaccine in China. Results The results of the gene sequencing showed the four clinical isolates belonged to ptxS1 A type, which were different from those in vaccine strains. In addition, three Prn and three Fim'3 variants were observed in the four clinical isolates. Sequence analysis showed that the nucleotide sequence and deduced amino acid sequence of those strains had more than 99% identity with those in vaccine strains. The phylogenetic trees of those genes also showed these strains had a higher level of similarity with other Bordetella pertussis strains. Conclusion The four clinical isolates are different from vaccine strains in four antigenic genes, which laid a foundation for further studies on pertussis epidemiology,quality control and development of pertussis vaccine in China.
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Objective To investigate the pathogen culturing of the catheter related infection(CRI),cathe-ter related bloodstram infection(CRB)and risk factors after central venous catheter(CVC)of cardiovascular surgery in order to provide the beneficial reference.Methods From Jan 2005 to Dec 2005,a total of 300 cases central ve-nous cathers were determined,and the cusp of the catheters was determined by bacteria cultivation,and blood bacte-ria cultivation.Results The infection happened in 35 of 300 patients with inserted central venous catheter.The cusps of CRI rate was 11.7%.CRB rate was 1.7%.54.3%pathogens were gram-positive cocci,34.3% were gram-negative bacilli,11.4% were fungi.The most common strain were Staphylococcus epidermis,Staphylococcus aureus,Klebsiella pneumoniae,Pseudomonas aeruginose,and Candiadia albicans.The infection rate increased obviously when the dwelling time>6 d.Conclusion CRI and CRB are the most severe complication of CVC,and it is important to cut down the death with the early diagnosis and applying antibiotics rationally.
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OBJECTIVE To find out the clinical characteristics of nosocomial infections with Stenotrophomonas maltophilia(SMA) and investigate the disinfectant resistant gene of qacE△1,improve the diagnosis and decrease of nosocomial infection cases.METHODS Toally 165 strains of SMA were clinically isolated from 2004 to 2007.The gene of qacE△1 was analyzed by polymerase chain reation(PCR) and homology of the strains was analyzed by the method of by pulsed field gel electrophoresis(PFGE) genotype.RESULTS Susceptible factors were old age,seriousness of underlying disease,prolonged hospitalization and invasive operation with infection of SMA.The lower respiratory tract infection was mostly common with SMA,rate of which was 87.9%.Antibiotic sensitive rate more than 80% against SMA was minocycline,trimethoprim-sulfamethoxazole and levofloxacin.The positive rate of gene qacE△1 was 13.3% in 60 strains tested.Two genotypes in SMA strains from respiratory ICU(RICU) were with the same clone.This result proved that clone transmission occurred in RICU.CONCLUSIONS SMA is an important nosocomial infection pathogen.With the multi-drug resistance,the therapy of infection with SMA is very hard in clinic.As result of gene of qacE△1 and the same clone transmission,clinicians should play an important role of surveillance of effect of disinfection.
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Objective To identify the genotype of clinical stenotrophomonas maltophilia(SMA) isolates and investigate the characteristics of SMA in nosocomial infections.Methods Totally 165 strains of SMA were clinically isolated during the period of 2004 to 2007.Disc diffusion test(K-B method) was used for antibiotic susceptibility.qacE△1 gene was detected by polymerase chain reation(PCR).The gene homology in the SMA strains was analyzed by pulsed field gel electrophoresis(PFGE).Results Among the tested SMA strains 87.9% sourced from low respiratory tract infection.The antibiotics with more than 80% of sensitive rate against SMA were minocycline,trimethoprim-sulfamethoxazole and levofloxacin.The positive rate of qacE△1 gene was 13.3% in 60 tested strains.The analysis of gene homology for the 11 clinical strains showed that two genotypes from identical clone were found in both respiratory ICU and emergency ICU respectively.Conclusions SMA was an important pathogenic bacterium in nosocomial infections.The treatment for SMA infection is very difficult since its multi-drug resistance.More attention for effective sterilization and isolation of patients must be paid to prevent the transmission of SMA from same clone.
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OBJECTIVE:To study the vitro antibacterial activity of domestic teicoplanin against224strains of enterococ-ci.METHODS:Determination of MIC of domestic teicoplanin against169strains of entercococcus faecalis and51strains of E.faecium was tested by agar dilution method,and its antibiotic effect was compared with that of the imported teicoplanin and other antibiotics.RESULTS:The MIC 50 of domestic teicoplanin against169strains of E.faecalis and51strains of E.faecium were0.125,0.25?g/ml respectively,MIC 90 were2,1?g/ml respectively;The MIC 50 of imported teicoplanin against E.faecalis and E.faecium were0.25,0.25?g/ml respectively,MIC 90 were1,0.5?g/ml respectively.CONCLUSION:Two kinds of te-icoplanin have strong antibacterial activity against224strains of enterococci;the sensitivity of224strains of enterococci to both kinds was100%.
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Objective To evaluate the in- vitro antibacterial activity of e thanol- extract of Galla Chinensis against Staphycoccus aureus (S. aureus).Meth ods The minimum inhibitory concentration (MIC50) of ethanol- extract of Galla Chinensis against 112 strains of S. aureus was detected by using agar dilution method.Results The MIC50 and MIC90 of ethanol- extract of Galla Chinensis aga inst 84 strains of MRSA (methicillin- resistant staphylococcus aureus) were 0. 315, 0.315 mg/mL, and those against 28 strains MSSA (methicillin- sensitive sta phylococcus aureus) were 0.63 and 0.315 mg/mL respectively.Conclusion Ethanol - extract of Galla Chinensis has a strong antibacterial activity against S.aure us.