Objective To evaluate the value of automatic bacteria identification systems including Phoenix and Vitek2 Compact, as well as blaOXA-51-like gene amplification in the identification of Acinetobacter species compared with amplified ribosomal DNA restriction analysis(ARDRA). Methods A total of 50 non-repeated clinical isolates of Acinetobacter species were collected in PUMCH from 2006 to 2007 and identified by ARDRA, blaOXA-51-like gene amplification, Phoenix and Vitek2 Compact,respectively. Results Compared with ARDRA, the sensitivity and specificity of blaOXA-51-like gene amplification were both 100%. The accuracy rates of Phoenix and Vitek2 Compact were 44% and 56%, respectively. Conclusions The accuracy of phenotypic identification of Acinetobacter species is not ideal, however, blOXA-51-like gene amplification could be used as a fast and reliable method for identification of A. baumannii. ARDRA is recommended in the study of drug resistant mechanisms and homological analysis of Acinetobacter species.

Objective:To investigate the effects of IL-12p35 small interference RNA on immune functions of Dendritic cells in rats.Methods:DCs were generated by culturing bone marrow progenitor cells of rats with GM-CSF, IL-4 and LPS in vitro. The IL-12p35 siRNA was synthesized and transfected into DCs. The expressions of CD80 and MHCⅡwere examined by flow cytometry. Reverse transcriptase PCR analysis was used to detect IL-12p35 mRNA transcription and ELISA was used to detect IL-12 and IL-10 protein levels, respectively. The antigen presenting by DCs was evaluated by mixed lymphocyte responses.Results:IL-12p35 siRNA silenced DCs expressed lower IL-12, higher IL-10,and exhibited weak activity in stimulating the proliferation of allogenic T cells, but no changes on CD80 and MHCⅡexpressions.Conclusion:IL-12p35 siRNA interference exerts no effects on maturation of DC, but negative effect on immume function of DCs.

Objective To analyze the clinical manifestations, computed tomography scan (CT), gastroscope, endo-scopic ultrasonography (EUS), and therapy method of gastritis cystica profunda. Methods Retrospectively analyzed clinical manifestations, CT, gastroscope, EUS, and pathological results of 6 cases of gastritis cystica profunda. Results In these 6 cases, 3 of them were doubted gastric carcinoma, 3 cases were considered stomach mass by CT. Gastroscope hinted apophysis lesions, but all cases were suggested gastritis cystica profunda by EUS. And all cases were removed through endoscopic submucosal dissection (ESD). Pathology were confirmed the diagnosis. Conclusion EUS combined with endoscopic mucosal resection (EMR) or ESD technique can improve the diagnostic rate. For gas-tritis cystica profunda which are not associated with malignant tumor can be treated through ESD.

Objective To investigate the antimicrobial resistance mechanisms and genetic homogeny of Salmonella from community acquired infections in Shenzhen,China.Methods Ninety-three of Salmonella were isolated from 2002 to 2007 at Shenzhen People's Hospital,China.PCR and DNA sequencing were used to investigate the mutation in QRDR of the gyrA,gyrB,parC and parE.Plasmid mediated quinolone resistance genes including qnr and aac(6')-Ib-cr,β-lactamase genes including blaTEM,blaSHV,blaOXA, blaCTX-M, and class 1 integron were detected. All isolates were typed by PFGE. Results S. enterica typhi and S. enterica paratyphi A were susceptible to ampicillin, chloramphenicol, trimethoprim/sulfamethoxazole, ceftriaxone and ciprofloxacin, with the susceptible rate of 96%-100%. Fifty-two percent (13/25) of S. enterica typhi and 95% (61/64) of S. enterica paratyphi A were resistant to nalidixic acid. Twenty-four percent (6/25) of nalidixic acid-resistant S. enterica typhi and 94% (60/64) of nalidixic acid-resistant S. enterica paratyphi A showed decreased susceptibility to ciprofloxacin (MIC of 0. 125-1 μg/ml).All nalidixic acid-resistant (susceptible to ciprofloxacin ) Salmonella (NARS) isolates had a single substitution in the QRDR of GyrA, and 91% (68/75) of these isolates carried the substitution Ser83Phe in GyrA. Two mutations in the QRDR of GyrA were detected in both of two ciprnfloxacin-resistant Salmonella,with the additional one mutation in the QRDR of parC. Plasmid mediated quinolone resistance genes including qnr and aac(6')-lb-cr were not detected in any isolate. The blaCTX-M-14 gene was detected in a ceftriaxoneresistant isolate of S. enterica paratyphi A, with ISEcpl located on the upstream of it. Three muhidrugresistant strains of Salmonella all carried one 1 900 bp classⅠ integron gene cassette dhfrⅫ-orfF-aadA2,with the additional one β-lactamase gene of blaTEM-1, or blaOXA-30. Twenty-two distinct PFGE patterns were observed among twenty-five S. enterica typhi. The PFGE patterns of sixty-four S. enterica paratyphi A showed limited genetic diversity (average similarity of 91% ). Ninety investigated inpatients were infected in the community. Six patients infected by S. enterica paratyphi A had a travel history before infection. Conclusions Nalidixic acid-resistant S. enterica typhi and S. enterica paratyphi A are highly prevalent in Shenzhen,China. The mutation in the QRDR of GyrA is the prevalent mechanism responsible for the resistance to nalidixic acid in Slmonella. The great genetic similarity among S. enterica paratyphi A isolates indicates endemic disease from the presence of a single clone over 6-year period.

Objective To evaluate the in vitro activity of daptomycin, vancomycin, teicoplanin, tigecycline, ceftobiprole and linezolid against 499 strains of blood-isolated gram-positive cocci. Methods Determination of the minimal inhibitory concentration (MICs) of daptomycin with microbrothdilution method and the MICs of other 9 antimicrnhial agents with agar dilution method against 499 strains of blood-isolated gram positive cocci was carried out. The data was analyzed with WHONET 5.4 software. Results The susceptibility rates of staphylococci to daptomycin, tigecycline, linezolid, ceftobiprole, vancomyein and teicoplanin were 100%. All staphylococcus strains were inhibited by daptomycin at a MIC of 1 mg/L. The MIC50 and MIC60 of daptomyein were both 0.5 mg/L against methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus coagalase-negative (MRSCnN). Among Enterococcus spp, the highest MIC of daptomycin was 4 mg/L. The MIC50 and MIC90 of daptomycin were both 2 mg/L against E.faecalis, whereas they were 2 mg/L and 4 mg/L against E.faecium. One strains of linezolid-resistant E.faecalis(MIC:8 mg/L)was susceptible to daptomycin (MIC: 1 mg/L). Three strains of E.faecium carrying vanA gene with vancomycin MICs above 32 mg/L and teicoplanin MICs also 32 mg/L were susceptible to daptomycin, tigeeycline and linezolid. The MIC range of daptomycin against Streptococcus pneumoniae and Streptococcus viridans was 0.032-0.25 mg/L and 0.125-1.000 mg/L separately. Conclusions Daptomycin has excellent in vitro activity against common gram-positive pathogens isolated from blood. It may be a good choice for clinicians to treat drug-resistant gram-positive cocci.

Objective To compare the in vitro activity of cefminox with other antimicrobial agents against clinical Escherichia coil, Klebsiella pneumoniae isolates and Bacteroides species. Methods MICs of sixteen antimicrobial agents against 945 Escherichia coli and 588 Klebsiella pneumoniae isolates from 15 teaching hospitals and MICs of four antimicrobial agents against 50 Bacteroides species isolates were determined by agar dilution method. WHONET 5.4 software was used to analyze the data. Results Among 1533 Escherichia coli and Klebsiella pneumoniae isolates, 628 isolates produced neither extended-spectrum beta-lactamases (ESBLs) nor AmpC, while 837 isolates produced only ESBLs and 68 isolates produced AmpC enzymes. The susceptibility rate of cefminox against non-ESBLs-producing or ESBLs-producing isolates was above 90%. MIC_(50) of eefminox was 2-4 fold lower than cefometazole and 8-16 fold lower than cefoxitin. MIC50 of cefminox was 2-8 fold lower than cefometazole and 8-16 fold lower than cefoxitin. Against ESBLs-producing isolates, the in vitro activity of cefminox was superior to the third and fourth generation cephalosporins, aztreonam, cefoperazone/sulbactam, levofloxacin, amikacin and inferior to carbapenems. Its activity was similar to piperacillin-tazobactam. The susceptibility rate of cefminox against AmpC-producing isolates was less than 20%. The susceptibility rate of cefminox against Bacteroides species was 90%, which was higher than that of cefometazole (50% -70%) and penicillin (0%) and similar to that of metronidazole. Conclusion Cefminox exhibites good activity against ESBLs-producing and non-ESBLs-producing Escherichia coli and Klebsiella pneumoniae isolates and Bacteroides species, which indicates that cefminox could be one of the options for the treatment of infections caused by these organisms.

Objective To investigate the prevalence of plasmid-mediated quinolone resistance qnr and aac(6')-Ib-cr in Enterobacteriaceac in Chiha.Methods A total of 197 clinical isolates with ciprofloxacin≥0.25μg/ml,cefotaxime≥2.0μg/ml and ceftriaxone≥2.0 μg/ml were screened from the 421 non-repetitive clinical isolates of Enterobac teriaceae(Escherichia coli,Klebsiella pneumoniae,Citrobacter freundii,and Enterobacter cloacae)from the nine teaching hospitals in China.qnrA,qnrB,qnrS and aac(6')-Ib gene were detected by PCR.aac(6')-Ib-cr gene was further identified by the digestion with BtsCI followed by sequencing.Conjugation experiments were done.The MIC of ciprofloxacin and other antibacterial agents in donor strain and acceptor strain were determined by agar dilution.Results Qnr was present in 42%(83/197)of isolares,and among these,17 isolates carried qnrA(9%),46 isolates carried qnrB(23%),24 isolates carried qnrS(12%),2 isolates carried qnrA and qnrB,and 2 isolates carried qnrB and qnrS.aac(6')-Ib was present in 46%(90/197)of isolates,40%(36/90)of which carried the cr variant responsible for low-level ciprofloxacin resistance.18 isolates carried qnr and aac(6')-Ib-cr.Qnr wag present in 66% of Enterobacter cloacae isolates,66% of Klebsiella pneumoniae isolates,63% of Citrobacter freundii isolates,and 6% of Escheriehia coil isolates,respectively,aac(6')-Ib-cr was present in 9% of Enterobacter cloacae isolates,22% of Klebsiella pneumoniae isolates,27% of Citrohacter freundii isolates,and 17% of Escherichia coil isolates,respectively,qnr and aac(6')-Ib-cr were present in 20% (83/421)and 9% (36/421) of all isolates respectively. The 13 transconjugants showed 16 to 125 fold increases in the MICs of ciprofloxacin and 16 to 31 fold increases in the MICs of levofloxacin relative to that of the recipient Conclusion Transferable plasmid-medlated low level quinolone resistance associated with qnr and aac(6')-Ib-cr widely exists in the enterobacteriaceae strains and perhaps this may contribute to the rapid increase of bacterial resistance to quinolones in China.

OBJECTIVE To investigate predisposing factors of candidemia in nosocomial infections.METHODS To retrospectively review the clinical features of 120 cases,including 59 who developed candidemia and 61 cases with bacteremia during the period of 1990-2004.RESULTS The incidence of candidemia was stable over a 14-year period.Candida albicans remained the predominant Candida species recovered(30.5%),followed by C.tropicalis(25.7%),C.glabrata(12.9%),C.parapsilosis(12.9%) and others(17.1%).Of the total 59 cases of candidemia,were administrated by broad spectrum antibiotic therapy for long time,urinary catheters,malignant tumor,etc.Multivariate analysis showed that candidemia was related with many factors.CONCLUSIONS C.albicans was the major pathogen in our hospital during 14 years;the candidemia is related with the use of quinolones,ventilator,central venous catheters and radiation-chemotherapy(P

Objective To investigate the effects of mefformin on the differentiation of osteoclastas well as relative mechanism.Methods Raw264.7 cells from the murine macrophage cell line was used.Receptor activator of NF-κB ligand (RANKL) was used to stimulate osteoclast differentiation from Raw264.7 cells.Osteoclast differentiation was assessed by tartrate-resistant acid phosphatase (TRAP) and actin fluorescence staining and counting the TRAP-positive cells after exposure to different concentrations of mefformin (0 μmol/L,400 μmol/L,800 μmol/L and 1000 μmol/L) or rapamicin (100 nmol/L) in the presence of 50 ng/ml RANKL for 5 days.Bone-resorbing activity was evaluated by BD BioCoatTM OsteologicTM Bone Cell Culture System.The expression of osteoclast-specific genes like TRAP,capthesin K,calcitonin receptor (CTR) and matrix metalloproteinase (MMP-9) was evaluated by RT-PCR.The expression of tumor necrosis factor-α(TNF-ct) S6K1Thr389,S6 Ser235/236,4E-BP1Thr37/46 and c-Fos protein was evaluated by ELISA kit and Western blot analysis,respectively.Results Mefformin dose-dependently inhibited RANKL-stimulated osteoclasts differentiation in Raw264.7 cell culture,as manifested by decrease of TRAP-positive multinucleated cells and pit erosion area,down-regulation of TRAP,cathepsin K,CTR and MMP-9 mRNA and reduction of TNF-α and c-Fos protein expression.Further study revealed that RANKL activated mTOR complex 1(mTORC1) signaling,while mefformin impaired RANKL-stimulated mTORC1 signaling.Rapamycin,an mTORCl-specific inhibitor and immunosuppressive macrolides could also prevent RANKL-induced osteoclast differentiation and bone resorption in vitro.Conclusion Mefformin inhibits osteoclastogenesis in vitro,which may due to reduction of TNF-α and c-Fos protein expression,and mTORC1 signaling is involved in this process.

ObjectiveTo investigate the prevalence,antibiotic characteristics as well as molecular background of community-associated methicillin-sensitive Staphylococcus aureus (CA-MRSA) from patients with skin and sofi tissue infections from 4 different hospitals in Beijing.MethodsFive hundred and one patients were enrolled from 4 hospitals prospectively.Patients with skin and soft tissue infections and no risk factors for healthcare-associated acquisition were included.Sample from the infection sites were collected for culture.Case report form was filled out for each patient.Antibiotic susceptibility test and molecular analysis was performed for each Staphylococcus aureus isolate.ResultsTotally 164 Staphylococcus aureus isolates were cultured from the patients with skin and soft tissue infections.Of them 5 isolates were CA-MRSA.These 5 CA-MRSA isolates harbored SCCmec Ⅰ, SCCmec Ⅲ, SCCmec Ⅳ,SCCmec Ⅴ and untypable,respectively.CA-MRSA was highly resistant to β-lactamase,levofloxacin,erythromycin and clindamycin,but susceptible to vancomycin,teicoplanin,linezolid,daptomycin,and trimethoprim/sulfamethoxazole.Prevalence of PVL in community-associated methicillin sensitive Staphylococcus aureus(CA-MSSA) and CA-MRSA were 41.9％ and 2/5.Other toxins expressed similarly between them.Combined with multilocus sequence typing (MLST) and spa typing,the major clones of CA-MSSA were ST398-t034,ST7-t796,ST398-t571,ST1t127,and ST188-t189,while in CA-MRSA were ST239-t037-SCCmec Ⅰ,ST239-t632-SCCmecⅢ,ST59-t437-SCCmecV,ST8-t008-SCCmecⅣ,and ST6-t701-NT.ConclusionsThe low prevalence of CA-MRSA in Beijing and complexity of the genetic background in CA-MRSA were observed.Clone spread is not found among CA-MRSAisolates.CA-MRSAexhibithigher resistancecomparedwithmethicillinsensitive Staphylococcus aureus (MSSA).Rational drug use scheme is called in the clinical practice to prevent development of high level resistance.