Ciprofloxacin抗藥性鼠傷寒及豬霍亂型沙門氏桿菌之分子流行病學及抗藥機轉
Molecular Epidemiology and Resistance Mechanisms of Ciprofloxacin-Resistant S. typhimurium and S. choleraesuis
Date Issued
2004
Date
2004
Author(s)
Tseng, Sung-Pin
DOI
zh-TW
Abstract
Salmonella enterica is one of the human pathogens that causes diarrhea and salmonellosis. Fluoroquinolones are often the choice of tratment in the case of salmonellosis. Unfortunately, the quinolone resistant strains significantly increased in recent year. To elevate the dissemination of this strain, clinical isolates from 1996-2001 were collected and analyzed. Pulsed-Field Gel Electrophoresis (PFGE) showed that majority of these clones that with identical serotype of S. enterica sharing similar PFGE pattern. This result suggested that these clinical pathogens were disseminated by similar source. In other word, this is the result of clone spreading effect. In addition, we collected animal infection strains and the result was compared with those clinical isolates. Interestingly, we found that some of the animal infection strains sharing the identical pulsoltype with clinical isolated, suggested that swine served as a reservoir for these resistant strains.
Recent study shows that the point mutation of topoisomerase and highly expressed of efflux pumps, such as acrAB operon, causes the bacteria increased the resistant ability to quinolone. Our sequencing results demonstrated the point mutation regions in quinolone resistance determination region (QRDR). Furthermore, organic solvent tolerance assay and ciprofloxacin accumulation assay showed the increasing activity of efflux pump in resistance strains. Northern blotting and Western blotting results confirmed the significantly increased expression level of acrA revealed that the activation of efflux pumps expression leads to the resistance effect in Taiwan. Besides, the stop codon mutation of acrR, an inhibitor of acrA, lost its function to inhibit acrA expression level resulting the over-expression of this efflux pumps. We also could not obtained the similar result in Salmonella typhimurium as S. enterica elevated that, except acrR, an unknown genes which might be involved in acrA regulatory system in resulting acrAB regulon increased its expression levels.
Subjects
沙門氏桿菌
抗藥
quinolone
drug resistance
PFGE
SDGs
Type
other
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