Objective To investigate the drug resistant genes against carbapenems,aminoglycosides and quinolones and the molecular epidemiology of clinical isolates of Acinetobacter baumannii.Methods Forty non-duplicate strains of Acinetobacter baumannii were collected from clinical specimens in First Affiliated Hospital of Wenzhou Medical University.The identification of strains was conducted by Vitek 2 Compact system.The susceptibilities to antimicrobials commonly used were determined by agar plate dilution method and broth microdilution method.The presence of class B metalloenzyme-encoding genes (blaIMP,blaVIM,blaNDM,blaSIM,blaGIM),class D cabapenemase-encoding genes (blaOXA-23,blaOXA-48,blaOXA-58),16S rRNA methylase genes (armA,rmtB) and quinolone resistance-determining regions (QRDR) in gyrA and parC were detected by polymerase chain reaction (PCR) and sequenced.Chromosomal or plasmid location of blaOXA-23 and armA genes were assessed by Southern blot.Multiple loci sequence classification (MLST) was performed to analyze the molecular epidemiology of these strains.Results All of the 40 isolates were multi-drug resistant Acinetobacterbaumannii (MDR-AB) and showed high level resistance to all of the tested antimicrobial agents excluding colistin and tigecycline.The positive rates of blaOXA-23 and armA were 90％ and 95％,respectively.All of the 40 isolates carried QRDR mutations in gyrA and parC genes,leading to the Ser83→ Leu and the Ser80→ Leu amino-acid substitutions,respectively.Southern blot showed the chromosomal location of blaOXA-23 and armA genes.Six different ST (ST191,ST381,ST373,ST426,ST208 and ST207) were assigned for these isolates by MLST and the most dominant clones were ST191 (23/40) and ST381 (10/40).Conclusions The predominant cabapenemase-encoding gene and 16S rRNA methylase gene of Acinetobacter baumannii isolates in First Affiliated Hospital of Wenzhou Medical University are blaOXA-23 and armA,respectively,which may be located on the chromosome and vertically transmit the drug resistance.ST191 MDR-AB with blaOXa-23 and armA gene clonally spread in this hospital.

Objective:To discuss dexamethasone on proliferation of mouse thyroid follicular cells and apoptosis. Methods:Taken BALB/c mice thyroid tissue to trypsin+Ⅱcollagenase digestion organizations get thyroid follicular cells,and expression of thyro-globulin determined whether or not the target cell. Then different concentrations of dexamethasone to stimulate target cells,and the use of MTT,flow cytometry cell proliferation rate,apoptosis rate and the apoptosis-related gene expression analysis. Results: Trypsin joint type Ⅱ collagenase treatment of thyroid tissue to obtain a stable passage of thyroid follicular epithelial cells,and cells stably expressing thyroglobulin. At the same time, different concentrations of dexamethasone on cell proliferation difference was statistically significant (F=8. 544, P<0. 05 ), and the suppression of drug action have interaction ( F = 4. 532, P<0. 05 );in addition, differently dexamethasone concentration 10-6 mol/L, 10-5 mol/L, 10-4 mol/L, the apoptosis rates were 13. 39% ± 0. 79%, 17. 43% ± 1. 38%, 26. 42%±1. 74%,both with 0 mol/L to plug betamethasone 4. 51%± 0. 06% apoptosis rate differences were statistically significant (P<0. 05,P<0. 01),while the difference in the expression of apoptotic genes trend still showed a dose-dependent manner. Conclusion:Dexamethasone can effectively inhibit thyroid follicular cell proliferation and induce apoptosis through a variety of apoptotic pathways.