Objective High-throughout sequencing of all plasmid of 206 strains of Klebsiella pneu-moniae using Solexa/Illumina sequencing technology in order to investigate the resistance for plasmids in Klebsiella pneumoniae. Methods Bacterial isolates were obtained over the years 2002-2008. Solexa/Illumi-na sequencing technology was used to sequence both samples (S1 and S2) to a depth of between 10-560 fold coverage. We used SOAP provided by BGI to find SNPS and use velvet package to assemble these sequences and gained some long sequences, and MAQ programs developed in the laboratory were used to annotate SNPs and compare lineage-specific mutations in SHV-ESBLs. Results The Metagenome of plasmid encodes a 13 variety of resistance-related genes with exceptionally high copy numbers, including ABC-type efflux pumps and 4 variety of β-lactamases, SHV-ESBLs is abroad presence. We systematically investigated single nucleo-tide substitutions in plasmids metagenome, and found an amount of nonsynonymous mutations in the SHV-ESBLs genes. Conclusion Probabily in press of positive selection, we can clearly see these nonsynonymous changes predominantly occurred in plasmid SHV-ESBLs genes. And our findings indicate a unspecial low-level resistance contribute to antimicrobial efflux in the metagenome of plasmid in Klebsiella pneumoniae.

Objective To study the genotypes of OXA-51-like carbepenemases in Aeinetobacter beumannii and its association with drug resistance. Methods The susceptibility of 174 Acinetobacter baumannii against ceftazidime, cefotriaxon, amikacin and ciprofloxacin were detected with disc diffusion method. The minimum inhibitory concentration (MIC) values for meropenem and imipenem were determined with an agar dilution method. VIM, IMP, OXA-23, OXA-24, OXA-51 and OXA-58 β-lactamase genes were determined by PCR. DNA sequencing and genotyping were performed against OXA-51 positivestrains. Results All 174 isolates were negative by PCR for genes OXA-24, OXA-58, IMP and VIM. OXA-23 and OXA-51were amplified in 15.5% (27/174) and 72.4% (126/174) isolates, respectively. Therewere 15.5% (27/174) isolates producing OXA-51-like and OXA-23 carbapenemase simultaneously. Among126 OXA-51-like carbapenemase producing strains, 82.5% (104/126)were OXA-66 genotype, whereas theremaining 17.5% (22/126) strains belong to other genotype. Eight novel OXA-51-like Genotype were foundin this study. Conclusions OXA-66 were the primary genotype of OXA-51-like carbapenemases in A.baumannii. OXA-66 were related to low-level carbapenems resistance and may be associated with resistanceof other drugs. We found new OXA-51-like genotype in clinic isolates of A. baumannii in this study.

Objective To research the distribution and the characteristics of the plasmid mediated quinolone resistant genes in Shewanella algae. Methods The qnr, qepA, aac(6')-Ib-cr genes were amplified by PCR, then the positive PCR products were sequenced to determine the gene type. The transferability of plasmid mediated quinolone resistance was ensured by conjugation experiment. MICs were measured by E-test. qnrA gene was mapped to plasmids to locate it. Results The qnrA gene were detected in the Shewanella algae, this is a newfound subgroup qnrA7, the GenBank accession no. was GQ463707, qnrB, qnrS,qnrC, qnrD, qepA and aac(6')-Ib-cr genes were not detected. qnrA7 reside in a plasmid about 33 kb, conjugation experiment was unsuccessful. The strain was susceptible to quinolones. Conclusion It deserves paying close attention to the report of an original qnrA subgroup in an isolate of water-borne species of Shewanella algae.

Objective To evaluate the feasibility and therapeutic efficacy of real-time virtual navigation system (RVS) combined with contrast-enhanced ultrasonography (CEUS) for hepatocellular carcinoma undetectable by conventional ultrasound and CEUS.Methods A total of 213 patients with 265 lesions (undetectable on conventional ultrasound but detectable by other imaging examinations) were enrolled in this study.CEUS was performed,and lesions which were detected with CEUS were given CEUS guided radio-frequency ablation (RFA) (CEUS group).RVS combined with CEUS was performed to locate the rest lesions and guide RFA (RVS + CEUS group).Diagnostic value and therapeutic efficacy of RVS + CEUS were assessed.Results In 256 lesions,174 (65.7％) could be detected with CEUS,and among the rest 91 lesions,82 (90.1％) lesions could be detected by RVS combined with CEUS.The technique effectiveness rate of RVS + CEUS was significantly higher than that of CEUS (x2 =18.85,P ＜0.0001).Complete ablation rate after one month in RVS+ CEUS group was 9t.5％ (75/82),which was significantly higher than that in CEUS group [86.2％ (150/174),P ＜0.05].Local progression in one year in CEUS group and RVS + CEUS group were 13.4％ and 10.9％,respectively.Conclusions RVS combined with CEUS is feasible for hepatocellular carcinoma undetectable by conventional ultrasonography and CEUS,and the therapeutic efficacy of RVS + CEUS guided RFA is satisfactory.

[ ABSTRACT] AIM:To investigate the effect of phycocyanin on the apoptosis of human laryngeal cancer HEP-2 cells and to explore the inhibitory mechanism of phycocyanin to tumor.METHODS:Highly purified phycocyanin was ex-tracted from spirulina.The effects of phycocyanin at different concentrations on the growth of human laryngeal cancer HEP-2 cells were detected by MTT assay.In addition, the cell structures were observed under electron microscope.The cell ap-optosis was analyzed by flow cytometry.The production of reactive oxygen species ( ROS) was measured by flow cytometry. Enzymatic activities of caspase-3,-8 and-9 were measured by chemical colorimatry.The expression of Bax, Bcl-2, Fas, P53, caspase-3 and caspase-9 at mRNA and protein levels was determined by RT-PCR and Western blot.RESULTS:MTT test confirmed that phycocyanin inhibited the cell activity of HEP-2 cells with time and dose dependent manners.The result of electron microscope observation and flow cytometry indicated that phycocyanin induced the apoptosis of HEP-2 cells.The intracellular content of ROS was increased.The activities of caspase-3, -8 and -9 were increased.RT-PCR showed that the mRNA expression of Bax, Fas, P53, caspase-3, caspase-9 was increased and Bcl-2 was decreased.The results of Western blot were consistent with the results of RT-PCR.CONCLUSION:Phycocyanin might induce apoptosis of HEP-2 cells by down-regulating Bcl-2, up-regulating Bax, Fas and P53, and the transduction of apoptotic signals in the human laryngeal cancer cells.

OBJECTIVE To investigate the distribution of integron in Gram-negative isolates which are causing nosocomial infection the association with drug resistance,and it′s contribution in horizontal transfer of drug resistance.METHODS Drug resistance test was performed by K-B method.ESBL-positive strains were detected by double-disk synergy test.Integron was determined by PCR assay with integron-specific-primer.Conjugative transfer test,plasmid profile analysis,nested-PCR,and DNA sequence analysis were used to investigate the transferable mechanism of integron mediated.RESULTS 66.4% of Strains were shown to be positive for classes Ⅰ integron,no class Ⅱ and Ⅲ integrons were detected.Profiles of class Ⅰ integron were 11 types,which sized from 700bp to 2300bp,gene cassettes included genes encoding resistance to aminoglycosides(aadA1,aadA2,aadA5 and aacA4),sulfamethoxazole/trimethoprim(dfrA12,dfrA5 and dfrA17) and chloramphenicol(catB8).Strains positive for class Ⅰ integron were highly related to multidrug resistance and ESBLs.Class Ⅰ integron could horizontal transfer along with plasmid among bacteria.CONCLUSIONS Class 1 integron is widespread in Gram-negative isolates which are causing nosocomial infection.Drug resistance is more liable to horizontal transfer via class Ⅰ integron along with plasmid.It implies the necessary for surveillance of horizontal transfer of antibiotic resistance gene among bacteria genus.

Objective To study the structures of the plasmids of Klebsiella pneumoniae KF3 at the genome metagenome level througth with whole plasmid DNA sequencing, to analyze the functional genes carried by plasmid and to identify the correlation of resistance and pathogenicity between the plasmids and the host strains. Methods The alkaline lysis method was used to extract plasmids. We constructed the small insert pUC18 library and the large insert Forsmid library, sequenced and used the Phred / Phrap / Consed package to assemble these sequences and gained a complete sequence. The open reading frame(ORFs) were predicted by the Glimmer software and annotated, analyzed the functions of these genes. Results We successfully constructed the pUC18 library and the Fosmid libraries for the plasmid DNA and obtained three circular double-stranded DNA plasmids: pKF3-70 (69 477 bp), pKF3-90 (91 327 bp) and pKF3-147 ( 147 416 bp). There were drug resistant genes, conjugative transfer genes and mobile DNA elements identified on three plasmids. Conclusion The three plasmids of KF3 could be transferred among different strains. It would lead to the dissemination of the resistant genes.

Objective To investigate the genotypes of host killing genes and their single nucleotide polymorphisms (SNPs). Methods Three hundred and twenty strains of Escherichia coli that collected from the First Affiliated Hospital of Wenzhou Medical College were analyzed. The first sample ( E1 ) contains 160 strains isolated during the years from 2002 to 2003. The second sample (E2) contains 160 strains covering the years from 2008 to 2009. The plasmids of Escherichia coli were extracted by alkaline lysis method. Solexa/Illumina sequencing technology was used to sequence plasmids metagenome. Solexa Genome Analysis System and Soap programs were used to analyze gene distribution, SNPs and lineage-specific mutations. Results 11 077 768 reads were generated and 0. 045% of them can map to the reference sequences from El sample. Whereas 9 377 792 reads were generated and 0. 053% of which mapped to the reference from E2 sample. There are nine host killing genes identified in the two samples, of which hok gene is the most prevalent. A total of 29 SNP sites dispersed in five genes of the two samples. Approximately 33% of them were non-synonymous mutations. One position of A and G is the most prevalent polymorphism. Conclusion The known nine genotypes of host killing genes were all identified in plasmids of Escherichia coli in Wenzhou. hok gene showed the highest frequency. There were SNPs in five genotypes.

OBJECTIVETo 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.

METHODSK-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.

RESULTS54.2%-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.

CONCLUSIONThe 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.

Anti-Bacterial Agents ; pharmacology ; Drug Resistance, Multiple, Bacterial ; genetics ; Enterobacteriaceae ; drug effects ; genetics ; Evolution, Molecular ; Integrons ; genetics

Objective:To explore the cleansing effect of Nitric Oxide (NO) sustained-release silica nanoparticles (short for NO sustained-release agent) on endoscopic biofilm and its clinical application.Methods:A total of 160 clinical endoscopes were randomly divided into two groups: the cleansing agent group (80 pieces, disinfected with cleansing agents), NO group (80 pieces, disinfected with NO sustained-release agent). A biofilm model of Pseudomonas aeruginosa was constructed and used as the control for phosphate buffered solution (PBS) treatment. A biofilm model of Pseudomonas aeruginosa on the surface of endoscopic lumen was built first in vitro. Scanning electron microscopy was then used to observe the microstructure of biofilm after treatment with NO sustained-release agent. Viable counting method was used to evaluate the cleansing effect of NO sustained-release agent on biofilm. Finally, at the clinical level, the actual disinfection effect of NO sustained-release agent on clinical endoscopy was evaluated by detecting the protein residues, viable counting and adenosine triphosphate (ATP) biofluorescence detection. Results:The scanning electron microscopy showed that the biofilm was intact in the model group, but scattered bacteria were observed on the biofilm surface in the NO group and the detergent group. Compared with the model group [(4.86±2.67)×10 6(colony-forming units, CFU)/mL], the standard CFUs of the NO group [(1.37±0.61)×10 4CFU/mL] and the detergent group [(1.31±0.21)×10 5CFU/mL] were significantly lower (detergent group VS model group, P=0.009; NO group VS model group, P=0.008), and there was significant difference between the detergent group and the model group ( t=9.53, P=0.000 6). The levels of residual proteins in the endoscopic lumens before and after the treatment were 8.03±1.47 mg/mL and 0.50±0.37 mg/mL in the NO group, 8.01±1.51 mg/mL and 0.91±0.52 mg/mL in the detergent group with significant difference ( P<0.01), and the reduction effect of the NO group was more significant. The disinfection of NO group and cleaning agent group was within the qualifying range, but the ATP bioluminescence value, protein residue and colony count of NO group (78.56±42.59 RLU, 0.50±0.37 mg/mL, 7.55±4.56 CFU) were significantly lower than those of detergent agent group (120.80±54.00 RLU,0.91±0.52 mg/mL,11.50±4.75 CFU, P<0.01). Conclusion:NO sustained-release agent can effectively clear endoscopic biofilm and further improve the disinfection effect on endoscopes, which may be of great significance for improving the effects on treatment and prognosis of patients.