| Objective: To study the Carbapenem resistant Enterobacteriaceae of clinical distribution, antibiotic drug resistance, resistance genotype and homology in our hospital and provides effective scientific guidance for the rational use of antibacterials and nosocomial infection monitoring.Method: Using WHONET 5.6 software statistics Enterobacteriaceae bacteria specimen types, distribution of departments and antibiotic drug resistance from January 2011 to December 2013, and at the same time screening separation of carbapenem resistant Enterobacteriaceae bacteria. For the postive bacteria, using ESBL phenotypic confirmation tests to investigate Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis the production of ESBL(Extended-spectrum beta-lactamase), using three-dimensional of cefoxitin to investigate the production of Amp C, using modified Hodge to investigate the production of carbapenemase, using EDTA synergistic inhibition to investigate the production of metal enzyme; using PCR amplification of common resistance genes(ESBL and Amp C enzyme genes, carbapenemase resistance genes, quinolone resistance genes and integrons genes); using plasmid conjugation experiments to investigate whether through conjugation to transfer drug-resistant plasmid; using PFGE(Pulsed field gel electrop Horesis) and ERIC-PCR(Enterobacterial repetitive intergenic consensus PCR) to investigate homology of carbapenem-resistant Enterobacter cloacae.Results: Over the past three years, a total of 7315 isolates of Enterobacteriaceae were isolated; the highest rate of separation were respiratory specimens(46.6%), followed by pus and secretion specimens(13.9%) and urine specimens(13.0%) from the source of specimen; the mainly department are pediatrics(17.5%), respiratory medicine(7.1%) and Intensive Care Unit(6.4%); the top three of bacterias were Escherichia coli(40.6%), Klebsiella pneumoniae(32.0%) and Enterobacter cloacae(15.3%); most of the antibiotic drugs have a higher rate of resistance, and only the carbapenem, enzyme inhibitor and aminoglycoside have also maintained a good antibacterial activity. At the same time, 18 carbapenem-resistance Enterobacteriaceae were collected, which including ten Enterobacter cloacae, three Proteus mirabilis, two Klebsiella pneumoniae and Escherichia coli, Enterobacter aerogenes and Citrobacter freundii each one. The positive rate of ESBL phenotypic confirmatory test was 66.7%(4/6), Amp C enzyme was 55.6%(10/18), modified Hodge experiment was 72.2%(13/18), EDTA synergistic inhibition test was 44.4%(8/18). For the results of resistance gene amplified, ESBL positive rate was 66.7%(so long as any sort of ESBL gene is sentenced to positive, the same below), Amp C enzyme resistant gene positive rate was 55.6%, carbapenem resistance gene positive rate was 77.8%, quinolone resistance gene positive rate was 77.8%, class I integron positive rate was 88.9%(16/18), class II integron positive rate was 11.1%(2/18), ISCR(Insertion sequence common region) positive rate is 72.2%(13/18). The positive rate of plasmid conjugation test was 66.7%(12/18), and the MIC of conjugant is far below the MIC of donor bacteria. PFGE and ERIC-PCR has a high homology with consistency, and also shows that no outbreak of infection occurrence in our hospital, which were scattered in the distribution.Conclusion: The resistant rate of Enterobacteriaceae in our hospital was high,and the majority of carbapenem-resistance Enterobacteriaceae was Enterobacter cloacae. Carbapenem-resistant Enterobacteriaceae can carry a variety of resistance genes, which major carbapenemases genes was NDM- 1 and KPC-2, and drug-resistant strains can transmit the resistant plasmid to susceptible strains. The same clone outbreak of carbapenem resistant Enterobacter cloacae did not appear and showing sporadic distribution. |
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