Drug resistance and protoporphyrin ferrochelatase of / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the drug resistance, β-lactamase-encoding genes and protoporphyrin ferrochelatase-encoding genes of, and to explore its structure and pathogenic function.</p><p><b>METHODS</b>The strain was isolated by plate streaking method and identified by automatic bacteria detection system and 16S RNA gene PCR. Microdilution method was applied for drug susceptibility test. β-lactamases, extended spectrum β-lactamases (ESBL) and carbapenemases were detected using nitrocefin-disk, Kirby-Bauer disk, and Hodge test, respectively. Five β-lactamase-encoding genes and protoporphyrin ferrochelatase-encoding gene of the isolate were amplified by PCR for sequencing. Bioinformatic softwares were used to analyze the structure and function of the product of protoporphyrin ferrochelatase-encoding gene.</p><p><b>RESULTS</b>A strain belonging towas isolated. This isolate was sensitive to cefepime, ciprofloxacin, ofloxacin and tigecycline, but resistant to five penicillins, four cephalosporins and two carbapenems antibiotics. The isolate produced β-lactamases but did not produce ESBL and carbapenemases. The isolate had five distinct β-lactamase-encoding genes and protoporphyrin ferrochelatase-encoding gene. The product of protoporphyrin ferrochelatase-encoding gene contained two functional domains of protoporphyrin ferrochelatase belonging to type Ⅱ chelatase superfamily that presented the most closely genetic relationship with the protoporphyrin ferrochelatase of.</p><p><b>CONCLUSIONS</b>The isolate ofhas a higher resistance to β-lactam antibiotics and its β-lactamase-encoding genes are different with the common bacterial β-lactamase-encoding genes. Protoporphyrin ferrochelatase may act as an important virulence factor of.</p>

Advances in bacterial extracellular metalloproteases and their pathogenic roles / 中华微生物学和免疫学杂志

Bacterial extracellular metalloproteases ( BEMPs) are a large group of metal ion-contai-ning proteases. All BEMPs identified so far are endopeptidase or endoprotease. BEMPs can be classified into nine metalloprotease families based on the sequences and structures of enzymatic molecules. Double-valence zinc ion ( Zn2+) is necessarily required by catalytic centers of most BEMPs. The main function of BEMPs in non-pathogenic heterotrophic bacteria is to hydrolyze environmental proteins and polypeptides to provide vari-ous amino acids as nutrients. However, BEMPs of pathogenic bacteria, serving as important virulence fac-tors, help the pathogens invade into hosts and spread in hosts. In recent years, the roles and mechanism of BEMPs in bacterial pathogenesis have attracted great attention. Here, we make a brief review about the structures and types as well as the functions and pathogenic roles of BEMPs.

Distribution characteristics and diversity of virulence genes in clinical isolates of vancomycin-resistant enterococci / 中国人兽共患病学报

The aim of this study is to determine the diversity of virulence genes carried by different vancomycin-resistant enterococci (VRE),which will provides a basis for studying pathogenic mechanism of VRE.Microdilution-based drug sensitivity test was applied to detect the vancomycin resistance of 490 Enterococcus faecium isolates and 862 Enterococcus faecalis isolates in Zhejiang area.The seven virulence genes (ace,asa1,cylA,efaA,esp,gelE and hyl) in the isolates of VRE were detected by PCR.According to the results of drug sensitivity test,10％ of the E.faecium isolates (49/490) and 0.8％ of the E.faecalis (7/862) were identified as VRE.In the vancomycin-resistant E.faecium isolates,five isolates were negative for any of the target genes and the other 44 isolates were positive for asa1,esp,gelE and hyl genes alone,in which the esp (73.5％,36/49) and hyl (53.1％,26/49) were the predominant genes and single or double virulence genes acted as the major carrying models.Except for the hyl gene,the vancomycin-resistant E.faecalis isolates were positive for the other six pathogenic genes,and the isolates could carry 3-6 pathogenic genes.All the data indicate that E.faeciurn is the major species of VRE in the local area,and the carrying rate,types and models of virulence genes in the vancomycin-resistant E.faecium and E.faecalis isolates are obviously different.

Isolation and identification of Neisseria gonorrhoeae strain from a balanoposthitis patient and drug resistance mechanism of the isolate / 中国人兽共患病学报

We isolated and identified the bacterial pathogen in a pyogenic balanoposthitis patient and investigated the drug resistance and its mechanism of the isolate.Urethral secretions and balanus pustule liquids were collected for microscopic examination after Gram-staining and detection of mycoplasma using Mycoplasma IST 2 kit.The two samples were inoculated on Columbia blood plate,N.gonorrhoeae selective plate and chromID Candida plate for isolation.The obtained colonies were identified by VITEK 2-compact automatic bacterial detection and analysis system.Moreover,PCR was performed to detect 16S rRNA gene of N.gonorrhoeae in the samples and colonies.KB method was applied for detecting susceptibility of five common antibiotics against the isolate.The β-lactamase and extended spectrum β-lactamase confirmatory tests were used to investigate the enzyme production of the isolate as well as drug resistance-associated tetM,TEM,mefA and ermF genes in the isolate were detected by PCR.Results showed that all the clinic samples showed negative for mycoplasma.All the isolating cultivation results of urethral secretions were negative while the balanus pustule liquids provided positive isolating cultivation in the blood and selective plates.The VITEK 2-compact system and 16S rRNA-PCR revealed that the isolated strain belongs to N.gonorrhoeae.The isolate can produce β-lactamases and resist to penicillin G,ciprofloxacin and tetracycline.The tetM,TEM,mefA and ermF genes could be found in the isolate's genome.The patient's balanoposthitis is caused by infection of N.gonorrhoeae.The multidrug resistance of Neisseria gonorrhoeae isolate is closely associated with its carried resistant genes.

Biological activity and pathogenicity of M23 superfamily metalloendopeptidases of Leptospira interro-gans / 中华微生物学和免疫学杂志

Objective To understand and determine the biological activity and pathogenicity of metalloendopeptidases encoded by LA2582 and LA2901 genes of Leptospira interrogans(L.interrogans) sero-group Icterohaemorrhagiaeserovar Lai strain Lai. Methods Structures and functions of LA2582 and LA2901 genes were analyzed by using bioinformatic software. Prokaryotic expression systems for expressing the extra-cellular regions of LA2582 and LA2901 genes were generated. The target recombinant expression products, rLA2582 and rLA2901,were extracted by Ni-NTA affinity chromatography. The Azo-casein-hydrolyzingactiv-ity of rLA2582 and rLA2901 was detected by spectrophotometry. Activities of rLA2582 and rLA2901 in the hydrolysis of Dabsyl-Leu-Gly-Gly-Gly-Ala-Edans, a fluorescence-labeling pentapeptide substrate, were de-tected by fluorospectrophotometry,and then the Km and Kcat values were determined. SDS-PAGE and spec-trophotometry were performed to detect the activities of rLA2582 and rLA2901 in hydrolyzing extracellular matrix molecules such as collagen type-Ⅰ (COL1), fibronectin (FN) and Congo red-labeling elastin (ELN). Real-time fluorescent quantitative RT-PCR(qRT-PCR) and Western blot were respectively used to measure the expression of LA2582 and LA2901 genes at mRNA and protein levels after infecting human um-bilical vein endothelial cells(HUVEC) with L. interrogans strain Lai. Results The gene products of LA2582 and LA2901 genes were identified as the signal peptide and matrix metalloproteinase motif HXH-containing Zn2+-dependent Gly-Gly metalloendopeptidases belonging to the M23 superfamily. rLA2582 and rLA2901 did not hydrolyze Azo-casein (Km=126.54 μmol/L, Kcat=4.67/s), but could hydrolyze the pentapeptide substrate (Km=190. 25 μmol/L, Kcat 4. 86/s). rLA2582 and rLA2901 could hydrolyze COL1, FN and ELN. Expression of LA2582 and LA2901 genes at both mRNA and protein levels was signifi-cantly increased after infection of HUVEC with L.interrogans strain Lai(P<0.05). Conclusion The prod-ucts of LA2582 and LA2901 genes of L.interrogans strain Lai are Zn2+-dependent M23 metalloendopeptidas-es, which can hydrolyze multiple ECM molecules and are closely associated with the leptospiral invasiveness.

The expression of ESBLs genes in Escherichia coli isolates induced by β-lactam antibiotics and inhibited by histidine kinase inhibitors / 中华微生物学和免疫学杂志

Objective To investigate the genotypes of extended spectrum β-lactamases (ESBLs) and their carrying modes in Escherichia coli (E.coli) isolates,and to analyze the mechanism of protein phosphorylation and ESBLs gene expression induced by β-lactam antibiotics or inhibited by histidine kinase inhibitors.Methods The predominant genotypes of ESBLs (KPC,TEM,SHV and CTX-M) and their carrying modes were identified by PCR and sequencing analysis.E-test and micro-tube dilution method were applied to measure minimal inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs).Immobilized metal ion affinity chromatography,bacterial protein phosphorylation detection kit and real-time fluorescent quantitation RT-PCR were performed to analyze the enhancing effects of 1/4 MIC penicillin or cefotaxime or the inhibitory effects of histidine kinase inhibitors (closantel,bromized or iodized methylimidazol) on protein phosphorylation and the expression of ESBLs at mRNA level in E.coli isolates.Results In 183 β-lactam antibiotics-resistant E.coli isolates,TEM and CTX-M genes (83.1％ and 77.1％) were highly expressed than other two ESBLs genes with a prevalent carrying mode of coexisting (65.0％) (P＜0.05).Penicillin or cefotaxime at 1/4 MIC induced the protein phosphorylation and promoted the expression of TEM,SHV and CTX-M at mRNA level (P＜0.05).Closantel (200 μmol),bromized methylimidazol (2 or 10 μmol) or iodized methylimidazol (20 or 50 μmol) could neither kill E.coli isolates nor inhibit their growth,but could inhibit the protein phosphorylation induced by above mentioned antibiotics and enhance the expression of ESBLs at mRNA level (P＜0.05).Moreover,the susceptibility of antibioticresistant E.coli strains to penicillin and cefotaxime were increased (P＜0.05).Conclusion TEM and CTX-M were the predominant genotypes of ESBLs carried by β-lactam antibiotics-resistant E.coli strains isolated from Zhejiang province,which were mostly found in a TEM plus CTX-M carrying mode.Sublethal dose of β-lactam antibiotics could up-regulate the expression of ESBLs genes in E.coli isolates via TCSS,but it could be inhibited by histidine kinase inhibitors.

Characteristics of clinical Shigella isolates por ducing the extended -spectrum and AmpCβ-lactamases / 中华微生物学和免疫学杂志

Objective To investigate the phenotypes and genotypes of extended -spectrum β-lacta-mases (ESBLs) and AmpC β-lactamases produced by cefoxitin-resistant Shigella strains isolated from Zhe-jiang province and the virulence of those strains .Methods Kirby-Bauer antibiotic testing was performed to screen cefoxitin-resistant strains from 356 Shigella isolates.The serotypes of the cefoxitin-resistant strains were detected .The phenotypes of ESBLs and AmpC β-lactamases from cefoxitin-resistant strains were detec-ted by ESBLs confirmatory test and AmpC-three-dimensional test ,respectively .The genotypes of ESBLs and AmpC β-lactamases were analyzed by PCR and sequence analysis .The virulence genes ( virA, ial, iapH, set1A, set1B and sen) in the cefoxitin-resistant strains were screened by PCR .Results Eight cefoxitin-re-sistant strains were identified from 356 Shigella isolates.Among them,six strains were identified as Shigella flexneri (S.fleaneri) strain (four F2a,one F2b and one F2c),and the rest were identified as Shigella sonnie (S.sonnei) strain.Among all eight cefoxitin-resistant strains,five strains showed positive results for ESBLs confirmatory test and two strains showed positive results for AmpC-three-dimensional test .Seven out of the eight strains harbor ESBLs genes (CTX-M-14,15,57 and/or OXA-30),two of which were positive for AmpC genes (DHA-1 and CMY-2).Five out of the eight cefoxitin-resistant strains carried all of the six tested viru-lence genes,while the other three strains possessed four virulence genes except for set1A and set1B.The two strains producing both ESBLs and AmpC β-lactamases were susceptible only to imipenem .Conclusion ESBLs positive isolates are prevalent strains of cefoxitin-resistant Shigella with potential high virulence .Some of them also produce AmpC β-lactamases ,and the DHA-1 type of AmpCβ-lactamase is identified for the first time in China .

Lipopolysaccharide and outer membrane proteins of Leptospira interrogans induce macrophage apop-tosis via Fas/FasL pathway / 中华微生物学和免疫学杂志

Objective To investigate the role of pathogenic Leptospira interrogans lipopolysaccha-ride (L-LPS) and outer membrane proteins (L-OMP) in the apoptosis of mouse macrophages (J774A.1) and their association with Fas/FasL pathway .Methods Phenol-water extraction and Triton X-114 phase separation were used to extract L-LPS and L-OMP from L.interrogans serogroup icterohaemorrhagiae serovar Lai strain Lai, respectively.Polymyxin B ( PMB) and protease K ( PK) were used to treat L-LPS and L-OMP, respectively.J774A.1 cells were stimulated by L.interrogans strain Lai with or without ultraviolet inactivation.In parallel, the cells were stimulated by extracted L-LPS and L-OMP with or without PMB and PK treatments .The apoptosis and necrosis of J 774 A.1 cells before and after treatment were detected by flow cytometry.The siRNAs were used to silence the expression of Fas or FasL gene in J 774A.1 cells and their inhibitory effects were further validated by using real-time fluorescent quantitative RT-PCR.Flow cytometry was used to detect the effects of L-LPS or L-OMP on the apoptosis of J774A.1 cells with Fas or FasL gene-knockdown .Results L.interrogans strain Lai with or without ultraviolet inactivation could cause similar early apoptosis rates (47.1%and 55.6%) and late apoptosis/necrosis rates (7.6%and 7.9%).The ear-ly apoptosis rates of 1×105 J774A.1 cells were 40.4%and 34.0%after the treatment with 100 ng of L-LPS and 100 μg of L-OMP for 4 h.The late apoptosis/necrosis rates of the cells were 7.5%and 6.9%upon the treatments with L-LPS and L-OMP, respectively.However, the apoptosis or necrosis of the cells was not ob-served when using L-LPS and L-OMP pre-treated by PMB and PK, respectively.Silenced expression of Fas or FasL gene reduced the L-LPS-induced J774A.1 cells apoptosis (P<0.05), while decreased early apopto-sis rate of J774A.1 cells mediated by L-OMP was only observed in Fas gene-knockdown cells (P<0.05). Conclusion Both L-LPS and L-OMP can cause the Fas/FasL-associated apoptosis of macrophages , which is beneficial for L.interrogans to establish the productive infection in hosts .

Distribution of drug inactive enzyme genes in bacterial isolates and mechanism of its induction and inhibition / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To determine the distribution and the predominant gene carrying model of drug inactive enzyme genes in bacterial isolates, and the mechanism of its induction and inhibition.</p><p><b>METHODS</b>The β-lactam, aminoglycosides and macrolides inactive enzyme genes were detected by PCR and sequencing in S. aureus, E.coli, K. pneumoniae, A. baumannii and E. cloacae isolates. The expression of inactive enzyme genes were examined by real-time fluorescent quantitative RT-PCR when the bacterial isolates were treated with antibiotics or a histidine kinase blocker closantel.</p><p><b>RESULTS</b>In 63 isolates of E.coli, 4 kinds of β-lactam, 2 aminoglycosides and 1 macrolides inactive enzyme-encoding genes were detected and the predominant gene-carrying models were [TEM+CTX-M]+aac(3)-II+mphA (25.4 %) and [TEM+CTX-M]+ aac (6')-I b (20.6%). In 24 isolates of S.aureus, 2 kinds of β-lactam and 3 aminoglycosides inactive enzyme-encoding genes were detected and the predominant gene-carrying models were aph (3')(41.7%) or aac (6)-I e-aph (2)-I a (25.0%). In 28 isolates of K.pneumoniae, 4 kinds of β-lactam and 2 aminoglycosides inactive enzyme-encoding genes were detected and the predominant gene-carrying models were [TEM+SHV]+[aac(6')-I b+aac (3)-II](28.6 %) and [TEM+SHV]+[aac(6')-I b+aac (3)-II]+ mphA (17.8 %). The isolates of A.baumannii and E.cloacae also had a predominant model to carry 2 or 3 kinds of inactive enzyme-encoding genes. 1/4 MIC of penicillin, cefotaxime or streptomycin induced the up-regulation of expression of 3 β-lactam or 4 aminoglycosides inactive enzyme-encoding genes (P<0.05), and this effect was inhibited by closantel (P<0.05).</p><p><b>CONCLUSION</b>The bacterial isolates frequently carry multiple kinds of inactive enzyme-encoding genes with different predominant gene-carrying models.Low concentration antibiotics can induce the up-regulation of inactive enzyme gene expression, which can be inhibited by histidine kinase blocker.</p>

Role of fliY gene in pathogenicity-associated chemotaxis and colonization of Campylobacter jejuni / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To construct a knockout fliY gene mutant strain of Campylobacter jejuni for determining the role of FliY protein in flagellar movement related to bacterial motility, chemotaxis and colonization.</p><p><b>METHODS</b>The plasmid pBluescript-II-SK was used to construct the suicide plasmid; according to homologous exchange principle, the suicide plasmid was utilized to generate fliY gene knockout mutant(fliY) in Campylobacter jejuni strain NCTC11168. The fliY mutant strain was identified by PCR, sequencing and Western blotting. The chemotactic and colonizing abilities of fliY mutant were determined by colony migration test and bacterial chemotactic test in vitro, and colonization test in jejunum of mice.</p><p><b>RESULTS</b>The fliY(-)mutant strain showed a growth curve in medium similar to that of wild-type strain. PCR, sequencing and Western blotting assay confirmed that the fliY gene in fliY(-)mutant was deleted. Compared to the wild-type strain, the colonies of fliY-mutant on semisolid plate were much smaller (P <0.05), the chemotactic ability of fliY mutant towards sodium deoxycholate and bovine bile was significantly attenuated (P <0.05), and the number of fliY mutant (CFU) in jejunal tissue specimens of the infected mice was significantly decreased (P<0.05).</p><p><b>CONCLUSION</b>The function of C.jejuni fliY gene refers to controlling flagellar movement, which is involved in bacterial chemotaxis and colonization.</p>

Multidrug resistance of enteric bacilli and its relation to structure and molecular evolution of variable region in resistance-related class-I integron / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the drug resistance of enteric bacilli and its relation to the drug resistance gene cassette in the variable region and molecular evolution of class-I integron.</p><p><b>METHODS</b>K-B assay was applied to measure the drug resistance of E.coli, E.cloacae and A.baumannii isolated against twelve antibiotics. The class-I integron and drug resistance gene cassettes in the variable region of the integron were detected by PCR and sequencing of amplification products. The molecular evolution of drug resistance genes in the class-I integrons was analyzed using Clustal X and MEGA software.</p><p><b>RESULTS</b>54.2%-100% of A.baumannii isolates were resistant to the penicillin and cephem antibiotics, while E.coli and E.cloacae isolates had resistance rates of 41.6%-62.5% to cephem antibiotics. 62.5%(15/24) of E.coli, 67.9%(19/28) of E.cloacae and 83.3%(20/24) of A.baumannii isolates were positive for class-I integrons. 81.5% (44/54) of class-I integrons showed 4 different single band spectrums and the other class-I integrons displayed 3 different double band spectrums. In the drug resistance gene cassettes in variable regions of class-I integrons there were 7 types in 4 groups of drug resistance genes, including aac(6'), sad(3"), aad(2"), cat(4') and dfr (types 7, A13 and 15), which induced the resistance to aminoglycosides and sulfamido antibiotics and chloromycin. The class-I integrons in the isolates might be divided into 4 molecular evolution groups according to the diversity of dihydrofolate reductase encoding gene sequences.</p><p><b>CONCLUSION</b>The enteric bacilli have a high drug resistance and frequently carry class-I integrons with 7 drug resistance gene cassettes which present 4 different evolutionary pathways.</p>

Expression changes of major outer membrane protein antigens in Leptospira interrogans during infection and its mechanism / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To determine expression changes of major outer membrane protein(OMP) antigens of Leptospira interrogans serogroup Icterohaemorrhagiae serovar Lai strain Lai during infection of human macrophages and its mechanism.</p><p><b>METHODS</b>OmpR encoding genes and OmpR-related histidine kinase (HK) encoding gene of L.interrogans strain Lai and their functional domains were predicted using bioinformatics technique. mRNA level changes of the leptospiral major OMP-encoding genes before and after infection of human THP-1 macrophages were detected by real-time fluorescence quantitative RT-PCR. Effects of the OmpR-encoding genes and HK-encoding gene on the expression of leptospiral OMPs during infection were determined by HK-peptide antiserum block assay and closantel inhibitive assays.</p><p><b>RESULTS</b>The bioinformatics analysis indicated that LB015 and LB333 were referred to OmpR-encoding genes of the spirochete, while LB014 might act as a OmpR-related HK-encoding gene. After the spirochete infecting THP-1 cells, mRNA levels of leptospiral lipL21, lipL32 and lipL41 genes were rapidly and persistently down-regulated (P <0.01), whereas mRNA levels of leptospiral groEL, mce, loa22 and ligB genes were rapidly but transiently up-regulated (P<0.01). The treatment with closantel and HK-peptide antiserum partly reversed the infection-based down-regulated mRNA levels of lipL21 and lipL48 genes (P <0.01). Moreover, closantel caused a decrease of the infection-based up-regulated mRNA levels of groEL, mce, loa22 and ligB genes (P <0.01).</p><p><b>CONCLUSION</b>Expression levels of L.interrogans strain Lai major OMP antigens present notable changes during infection of human macrophages. There is a group of OmpR-and HK-encoding genes which may play a major role in down-regulation of expression levels of partial OMP antigens during infection.</p>

Distribution of Salmonella paratyphi A pagC gene and immunoprotective effect of its recombinant expressed products / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To determine the distribution and sequence conservation of pagC gene in Salmonella paratyphi A isolates, and the immunogenicity and immunoprotection of its recombinant expression products (rPagC).</p><p><b>METHODS</b>The distribution of pagC gene in Salmonella paratyphi A isolates and its sequence conservation were examined by PCR and sequencing. A prokaryotic expression system of pagC gene was constructed and the expressed rPagC was extracted by Ni-NTA affinity chromatography. SDS-PAGE and Bio-Rad Gel Image Analyzer were applied to examine the expression and yield of rPagC. The antigenicity and immunoreactivity of rPagC were detected by immunodiffusion test, ELISA and Western Blot assay. The immunoprotective effect of rPagC against infection of Salmonella paratyphi A in mice was determined, while the agglutinative effect of sera from rPagC-immunized mice was measured by micro-Widal's test.</p><p><b>RESULTS</b>All the Salmonella paratyphi A isolates tested had the pagC gene, the similarity of nucleotide and amino acid sequences was 99.1 %-100 % and 98.4 %-100 %, respectively. The constructed prokaryotic expression system expressed rPagC with high efficiency. The rPagC immunized rabbit produced a high level antibody and it also combined with antiserum against whole cell of S. paratyphi A to generate a positive Western hybridization signal. ELISA results indicated that 97.1 % (66/68) paratyphoid patients infected with Salmonella paratyphi A were positive for rPagC antibody in their serum specimens. When mice were immunized with 100 μg or 200 μg rPagC, the immunoprotective rates were 73.3 % (11/15) or 86.7 % (13/15), respectively. The sera from rPagC-immunized mice offered 1:10-1:40 agglutination titers with the H antigens of Salmonella paratyphi A and Salmonella typhi.</p><p><b>CONCLUSION</b>PagC gene has an extensive distribution in Salmonella paratyphi A isolates. rPagC can be used as the candidate antigen in genetic engineering vaccine due to its fine immunogenicity and powerful immunoprotective effect.</p>

Genotypes ofβ-lactamase in Klebsiella pneumoniae isolates and induction and inhibition of theβ-lac-tamase gene expression / 中华微生物学和免疫学杂志

Objective To investigate the predominant genotypes of β-lactamase in Klebsiella pneu-moniae isolates and the mechanism of antibiotic and histidine kinase inhibitor in affecting β-lactamase gene expression .Methods Tube dilution method and E-test were used to detect the susceptibility of K.pneumon-iae isolates to β-lactam antibiotics .The major genotypes of β-lactamase in β-lactam antibiotic-resistant iso-lates were identified by PCR and sequencing method .Disk diffusion test was performed to analyze the activity ofβ-lactamase .The effects of cefotaxime and histidine kinase inhibitor closantel on the expression of β-lac-tamase gene were evaluated by real-time fluorescent quantitative RT-PCR.Results All of the 118 β-lactam antibiotic-resistant K.pneumoniae isolates expressed β-lactamase, 90.7%(107/118) of which were KPC-2, TEM-1, CTX-M-14, SHV-11 and/or OXA-1 gene positive.The positive rates of TEM-1 (71.0%) and SHV-11 (64.5%) were significantly higher than that of the other three genotypes ( P<0.05).68.2%(73/107) of the isolates possessed two or more than two β-lactamase genotypes, and 30.8%(33/107) iso-lates were identified as TEM-1+SHV-11 genotype.Except for KPC-2 mRNA, the levels of TEM-1, SHV-11, CTX-M-14 and OXA-1 mRNA were significantly up-regulated by cefotaxime at MIC/4 (P<0.05), but were inhibited by 100μmol/L closantel (P<0.05).Conclusion TEM-1 and SHV-11 are the majorβ-lactamase genotypes carried by K.pneumoniae strains isolated from Zhejiang area , and TEM-1 plus SHV-11 ( TEM-1+SHV-11) is the predominant carrying mode of the β-lactamase genotypes .Sublethal dose of cefotaxime can enhance the expression of β-lactamase genes in K.pneumoniae, while the histidine kinase inhibitor , closan-tel, can block the increased expression of β-lactamase genes induced by cefotaxime .

Molecular characteristics of Salmonella typhi and Salmonella paratyphi A isolates in Hangzhou area / 中华微生物学和免疫学杂志

Objective To determine the molecular characteristics of predominant Salmonella typhi and Salmonella paratyphi A strains prevalent in Hangzhou area from 2002 to 2008.Methods Pulse field gel electrophoresis (PFGE),multi-locus variable-number tandem repeat analysis (MLVA) and multi-locus sequence typing (MLST) were applied for typing as well as analysis of the molecular characteristics of 31 S.typhi isolates and 404 S.paratyphi A isolates from Hangzhou area during 2002 to 2008.Results The 404 S.paratyphi A isolates could be divided into six PFGE types (P1-P6).99.0％ of the S.paratyphi A isolates (400/404) belonged to the same one clone family (P1 and P2 types),in which P1 strains occupied 93.3％ (373/400) of the isolates.The 31 S.typhi isolates displayed a high diversity,which could be classified into 14 PFGE types,28 MLVA types with 90.3％ resolving power and 3 MLST types.The S.typhi strains prevalent in Hangzhou area were similar to those in Southeast Asia but different from those in Europe.The variable number tandem repeat (VNTR) sites with high polymorphism,TR1,TR2 and Sal02,could be used to the markers for diagnosis of S.typhi isolates in the area.The MLST types of 31 S.typhi isolates included all the three types currently found in the world but the ST2 type of S.typhi strains was predominant (23/31,74.2％).Conclusion The paratyphoid A prevalence in Hangzhou area in the recent years is caused by infection of the same clone family of S.paratyphi A whereas the S.typhi strains prevalent in the area display a high diversity.

Clinical study on the treatment of knee osteoarthritis combined with synovitis with Gubiqing / 国际中医中药杂志

Objective To observe the effects of treating knee osteoarthritis(KOA)combined with synovitis with Gubiqing,and discuss its mechanism.Methods A total of 60 cases with KOA were randomly recruited into a control group and a treatment group,30 cases in each.TCM symptoms,signs and health assessment questionnaire(HAQ)were observed before and after the treatment.Results The tohal therapeutic effect was 90%and 70%in the treatment group and the control group respectively.There was significant difference between the two group(χ~2=48,P=0.003).Body signs and HAQ were also greatly improved in the treatment group(t=0.004、P=0.008).Conclusion Gubiqing can not only restrain chondrocyte apoptosis in knee osteoarthritis combined with synovitis,but also relive the damage of articular cartilage.

Clinical study on the Treatment of 85 cases of Type 2 Diabetes Mellitus Combined with Abnormal Metabolism of Lipid with Quyuhuatan Decoction / 国际中医中药杂志

Objective To explone the therapeutic effect and mechanism of Quyuhuatan decoction in treating type 2 diabetes mellitus combined with abnormal metabolism of lipid. Methods 85 cases of type 2 diabetes mellitus combined with abnormal metabolism of lipid were recruited into a control group and a treatment group randomly. The treatment group (45cases) was treated with Quyuhuatan decoction and subcutaneous insulin injection while the control group(40cases) was treated with subcutaneous insulin injection exclusively. Both groups received the treatment for for 8 weeks. The result of TC, TG, LDL-C, and HDT-C were observed before and after the treatment. Results The improvement of blood lipid in the treatment group was superior to that in the control group (t=0.011, P<0.05) . Conclusion Quyuhuatan decoction is effective in treating type 2 diabetes mellitus combined with abnormal metabolism of lipid. The mechanism might be related with its cutting off pathological paths of hyperlipidemia.

Clinical Observation on Treatment of Chronic Superficial Gastritis of Spleen-stomach Dampness-heat Type with QingReHuaShi Recipe / 国际中医中药杂志

Objective To explore the therapeutic effect, mechanism and safety of Qingrehuashi recipe in treating chronic superficial gastritis with erosion pertaining to spleen-stomach damp-heat syndrome. Methods 84 cases of chronic superficial gastritis with erosion were recruited into a control group and a treatment group randomly, with each groups containing 42 cases. The treatment group was treated with Qingrehuashi recipe, while the control group was treated with Qingweizhitong granule. Both groups were treated for 8 weeks. The clinical manifestations and signs, gastroscopic results and pathological effects were observed before and after the treatment. Results The total effective rate and curative rate in the treatment group were superior to those in the control group (P<0.05) . Conclusion Qingre Huashi recipe is effective and safe in in treating chronic superficial gastritis with erosion pertaining to spleen-stomach damp-heat syndrome. The mechanism might be related to its effects of anti-inflammation, anti-oxidation, eradicating Hp, promoting gastric motility and enhancing gastric mucosal barrier.