Molecular Characteristics of blaOXA-23-Producing Acinetobacter baumannii Isolated from a University Hospital / 대한임상미생물학회지

BACKGROUND: Multi-drug resistant (MDR) Acinetobacter baumannii has emerged as a significant infectious agent in hospitals worldwide. The purpose of this study was to determine the molecular characterization of MDR A. baumannii clinical isolates. METHODS: Two hundred eighty-five strains of non-duplicated A. baumannii collected from March to November 2011 from a university hospital laboratory located in the Wonju area of the Gangwon province of Korea were analyzed for MDR genes. RESULTS: All of the 285 imipenem-resistant A. baumannii isolates were encoded by a blaOXA-23-like gene, and all isolates with the blaOXA-23-like gene had the upstream element ISAba1. The 16S rRNA methylase gene armA was detected in 153 (50.2%) clinical isolates, but rmtA, rmtB, rmtC, rmtD and npmA were not detected in any isolates in the present study. The gene encoding aac(6')-Ib was the most prevalent aminoglycoside-modifying enzyme. The sequencing data for the quinolone resistance-determining region of gyrA and parC revealed the presence of Ser (TCA) 83 to Leu (TTA) and Ser (TCG) 80 to Leu (TTG) substitutions. All but one of the 285 A. baumannii isolates showed similar band patterns on repetitive extragenic palindromic-PCR profiles. CONCLUSION: The molecular characteristics of the resistance genes of MDR A. baumannii isolates obtained from the Wonju area of Gangwon province were similar to those of other areas in Korea.

Reversal of multidrug resistance by transfection of tumor necrosis factor ? and MDR1 antisense RNA into multidrug resistant breast cancer cell line / 中国病理生理杂志

AIM:To study the reversal effects of multidrug resistance by transfecting tumor necrosis factor ?(TNF-?) cDNA and multidrug resistant 1(MDR1) gene antisense RNA into multidrug resistant breast cancer cell line MCF-7/ADR.METHODS:The recombinant vector of enhanced green fluorescent protein(EGFP) with MDR1 antisense RNA and recombinant vector of red fluorescent protein(DsRed2) with TNF-? cDNA were constructed by RT-PCR and DNA recombinant techniques.The recombinant vectors were transfected into multidrug resistant breast cancer cell line MCF-7/ADR.The cell growth curves,cell apoptosis rates,MDR1 gene expression at mRNA and P-gp levels,and the sensitivity to ADR were determined before and after the transfection.RESULTS:After the transfection,cells showed lower growth rate,higher apoptosis rate,lower MDR1 expression at mRNA and P-gp levels,and the sensitivity to ADR increased significantly.CONCLUSION:Transfection of TNF-? cDNA and MDR1 antisense RNA into multidrug resistant breast cancer cells may have good effects on reversal of multidrug resistance.