Molecular characterization of vancomycin-resistant Enterococci / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the homology and resistant mechanism of vancomycin-resistant Enterococci (VRE) isolates.</p><p><b>METHODS</b>A total of 9 VRE isolates were collected from 2006 to 2007 at PUMC hospital. The susceptibility of these isolates to 10 different antibiotics including vancomycin was tested by E-test. These strains were processed by brain heart infusion agar screening in the presence of vancomycin (6 microg/ml), and were analyzed for genotypic characteristics using the multiplex PCR. The homology of the isolates was determined by pulsed-field gel electrophoresis (PFGE).</p><p><b>RESULTS</b>All the 9 VRE isolates were identified as Enterococci faecium. The visual analysis of PFGE patterns revealed 6 different PFGE types. The vanA gene was confirmed by PCR and sequencing in 9 VRE isolates, which were consistent between phenotype and genotype for glycopeptides resistance.</p><p><b>CONCLUSIONS</b>Only vanA genotype was detected in PUMC hospital. Clonal dissemination, horizontal gene transfer, and the selective pressure of antimicrobial agents may contribute to the increase of VRE.</p>

Genotype distribution of extended-spectrum and AmpC ?-lactamases produced by Escherichia coli and Klebsiella pneumoniae in 10 teaching hospitals of China / 中国感染与化疗杂志

Objective To investigate the genotype distribution of extended-spectrum?-lactamases(ESBLs) and AmpC?-lacta- mases produced by Escherichia coli and Klebsiella pneumoniae in 10 teaching hospitals of China.Methods 90 clinical strains of E.coli and 61 strains of K.pneumoniae isolated in 2003 and confirmed to produce ESBLs were collected from 10 teaching hos- pitals in China.Analytical isoelectric focusing was used to measure the pI of the?-lactamases.Conjugation experiment was used to study the transfer of cefoxitin resistance.Plasmid-mediated AmpC enzyme genes were amplified and sequenced by multiplex polymerase chain reaction (MPCR).Results The prevalence of ESBL-producing E.coli and K.pneumoniae was about 50% in Wuhan,Nanjing and Jinan.The prevalence of ESBL-producing E.coli was lower than K.pneumoniae in Beijing.However,in other hospitals the prevalence of ESBL-producing E.coli was a little higher than K.pneumoniae.About 24.4% of ESBL-pro- ducing E.coli isolates and 19.4% of ESBL-producing K.pneumoniae isolates were resistant to cefoxitin.Cefoxitin-resistant i solate was identified in all hospitals except Shenyang.Major genotype of ESBL-producing isolates was CTX-M.The CTX-M-9 group was the most common group,followed by CTX-M-1.More K.pneumoniae isolates produced both ESBLs and AmpC en- zyme than E.coli.The genotype was CTX-M/DHA-1.The PCR results of 3 transconjugants producing both ESBLs and AmpC enzyme were the same as their donor isolates.Conclusions The genotype of ESBL-producing isolates is mainly CTX-M-9 group in these teaching hospitals.More K.pneumoniae isolates produced both ESBLs and AmpC enzyme than E.coli.Most of these isolates are due to geno type CTX-M/DHA-1,which can spread through plasmid.

Effect of Pirenzepine Injected Intravitreously on Retinal Blood Flow in Cats / 上海第二医科大学学报

0.05). In the group of pirenzepine, the RBF, velocity and volume significantly increased at 0.5 h and 1 h after injection compared with that before injection (P0.05). Conclusion These results suggest that pirenzepine could increase RBF and oxygen in blood with the peak time at 0.5 h and 1 h after intravitreous injection.